A may on: THE TAXONOMY AND ECOLOGY or MtCHIJGAN Ipssmos‘ Thai; for the Degreé bf Ph. D. ‘ MICHIGAN sm‘ECOLLEGs Wilbert Ernest Wade ' 1952 This is to certify that the thesis entitled A STUDY OF THE TAXONOMY AND ECOLOGY OF MICHIGAN DESMIDS presented by Wilbert Ernest Wade has been accepted towards fulfillment of the requirements for M degree in Many—and Plant Pathology ’ u/r 'Major professor mew -«—. c 'I I r . .- 'i-oA. ' .’ u.. . n... ”a Wilbert Ernest Wade candidate for the degree of Doctor of Philosophy Final examination: August 4, 1952, 9:00 A.M., Botany Seminar Room A Study of the Taxonomy and Ecology of Dissertation: Michigan Desmids Outline of Studies Major Subject: Botany Minor Subjects: Zoology, Entomology Biographical Items Born, September 22, 1922, Sharon, Pennsylvania Undergraduate Studies, Albion College, 1940-1943, cont. 1946-1947, Universitzfof Michigan Biological 0 Station, Summers, 1942, 19 Graduate Studies, Michigan State College, 1947-1952. Experience: Undergraduate Assistant, Albion College, 1946, Graduate Assistant, Michigan State College, 1947-1952, Stream Survey Bio- logist, Academy of Natural Sciences of Philadelphia, Summer, 1951. Instructor, Gulf Coast Research Laboratory, Ocean Springs, Mississippi, Summer, 1949. Mem- ber United States Army 1943-1946. Member of Society of the Sigma Xi, Phycological Society of.America, Michigan Academy of Science, Arts and Letters. A STUDY OF THE TAXONOMY AND ECOLOGY OF MICHIGAN DESMIDS ' By Wilbert Ernest Wade . 3- AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfill- ment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Botany and Plant Pathology Year 1952 Approved é £1! {22“‘& 0-... .r _ I. ‘ “v.1.-. UA\ A. ‘ . 9' ‘- -_‘. . In ."I . I I... ‘ 0“ l‘ ‘0‘ "'s u ‘I 0 \t ‘ ~ n. ~"‘ II I..“ b. o 0 .0 I. ' u u-" . ’V ‘O- ‘ u I i.“ Wilbert Ernest Wade This is a study of the distribution and classification of Michigan desmids. The term desmid is applied to algal organisms belonging to several families of the Order of Zyg- nematales in the Division Chlorophyta (green algae). Their great range of cell architecture and their usually calciphobic nature offer many phycologists an interesting field for study. The state of Michigan with its large number of bodies of water, as well as its varied physiography and soils, provides an excellent area for the study of the ecology and taxonomy of these organisms. The primary objectives of this study have been: (1) the collection and identification of desmids from various regions of the state, particularly from the areas of the southern lower peninsula and western upper peninsula where only a few reports are available; (2) the determination, if possible, whether desmid abundance in various regions of the state is correlated with major geological or soil features; (3) the assembling of previous distribution records of the desmids in the state together with those of the writer's into a uni- fied volume . TWO main portions comprise the report of this investi- gation. The first portion consists of chapters dealing with the general morphology, classification and distribution of Brief discussions of the major physiographic and The second por- desmids . soil regions of the state are also included. 1.7).: ) 4; 9‘!) i I A"‘I' “J $-14. I K‘ Wilbert Ernest Wade tion deals with the distribution and systematics of desmids in Michigan. The systematic section is based in part upon more than two hundred fifty samples made by the writer from seventy five stations throughout the state. The assembling of this data together with previous published records results in a total of seven hundred fifty one species, varieties and forms (including previous records) being considered. Arti- ficial keys to genera and species are provided in addition to a standard reference, brief diagnostic comments, measurements and distributional data (in Michigan) for each species, var- iety or forma. Thirty-five plates and three maps supplement the written text. Nineteen new species, varieties or formas are reported for the first time. A discussion of desmid distribution in the state in re- lation to major physiographic and soil regions is presented. 0n the basis of available distributional records, it gener- ally appears that the greatest abundance of desmids is cor- related with regions of the state where the lithologic com- DOSition of the surface deposits has the least limestone influence, whereas the poorest representation occurs in re- gions where the limestone influence is greatest. A STUDY OF THE TAXONOMY AND ECOLOGY OF MICHIGAN DESMIDS By Wilbert Ernest Wade A THES IS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfill— ment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Botany and Plant Pathology 1952 '- ouv .. E. “ n ."i" '. '- ts. ': u ‘s l \A." I - I... Acknowledgments The writer wishes to express his sincere thanks to Dr. G. W. Prescott, under whose supervision the following investigation was undertaken. His unfailing interest, help- ful advice and continued guidance have been of great inspir- ation to the writer during the course of this study. Special thanks are also extended to Dr. W. B. Drew, Head of the Department of Botany and Plant Pathology, for his advice and assistance during the absence of Dr. Prescott. Grateful acknowledgment is also due Dr. L. M. Turk, Head of the Department of Soils for the use of soil maps, and to Mr. J. 0. Veatch and Mr. I. F. Schneider, also of the Soils Department, for advice and helpful suggestions concerning soils. Acknowledgments are also due Dr. M. L. Britton of the Department of Botany of Northwestern University and Mr. Lee Famham for use of collections. A STUDY OF THE TAXONOMY AND ECOLOGY OF MICHIGAN DESMIDS By Wilbert Ernest Wade AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfill- ment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Botany and Plant Pathology Year 1952 Approved - W PM— !” 39"“; A,” r. Wilbert Ernest Wade This is a study of the distribution and classification of Michigan desmids. The term desmid is applied to algal organisms belonging to several families of the Order of Zyg- nematales in the Division ChlorOphyta (green algae). Their great range of cell architecture and their usually calciphobic nature offer many phycologists an interesting field for study. The state of Michigan with its large number of bodies of water, as well as its varied physiography and soils, provides an excellent area for the study of the ecology and taxonomy of these organisms. The primary objectives of this study have been: (1) the collection and identification of desmids from.various regions of the state, particularly from.the areas of the southern lower peninsula and western upper peninsula where only a few reports are available; (2) the determination, if possible, whether desmid abundance in various regions of the state is correlated with major geological or soil features; (3) the assembling of previous distribution records of the desmids in the state together with those of the writer's into a uni- fied volume. Two main portions comprise the report of this investi- gation. The first portion consists of chapters dealing with the general morphology, classification and distribution of ' desmids. Brief discussions of the major physiographic and soil regions of the state are also included. The second por- tint: is. u . 5.5:, l‘slg. “"‘s. tint. My; " I '-“.‘.A U.."‘ E3; 19:: la: Wilbert Ernest Wade tion deals with the distribution and systematics of desmids in.Michigan. The systematic section is based in part upon more than two hundred fifty samples made by the writer from seventy five stations throughout the state. The assembling of this data together with previously published records re- sults in a total of seven hundred fifty one species, varie- ties and forms (including previous records) being considered. Artificial keys to genera and species are provided in addi- tion to a standard reference, brief diagnostic comments, measurements and distributional data (in Michigan) for each species, variety or forma. Thirty-five plates and three ,maps supplement the written text. Nineteen new species, var- ieties or formas are reported for the first time. A discussion of desmid distribution in the state in re- lation to major physiographic and soil regions is presented. On the basis of available distributional records, it generally appears that the greatest abundance of desmids is correlated with regions of the state where the lithologic composition of the surface deposits has the least limestone influence, whereas the poorest representation occurs in regions where the lime- stone influence is greatest. v“.. 0 . but... " I. ‘.-. . . “ ~¢--.. 99. 1 ”I . .. o..u I ~ ’ so.» .' ”o q a). "'5“ Iv.._. . A. e 0‘ ‘x ' 9. 'I I- ~A.. W. it. .“ Q‘. ' . - N. l ..I W... ‘ ".. ”‘Iv. 4...: . 7 ., ‘ d“ ..J v...‘ s l ‘1 I g ‘ Q... I n .I h I a. I e ‘_ 0. ‘\| H l». \‘. :3: ”s R N \ ‘o. "t, "\ 8,? \c. F- p d Table of Contents I. Introduction . . . . . . . . . . . 1 II. History of Study of Desmids in Michigan . . 2 III. History and Objectives of Problem. . . 4 IV. General Morphology and Classification of Desmids . . . . . . . . . . . . . . . . . . . . 7 11 V3 The Distribution of Desmids VI. Factors Determining the Occurrence and Distribution of Desmids . . . . . . . . . . . . 13 VII. Methods and Procedures . . . . . . . 17 VIII. General Physiography of Michigan . . 2O Ix. Soil Regions of Michigan . - 25 . 31 X. Discussion and Results . . . . . . . . . . . . . . . . . . . . . . . . . 31 A- General Data . . . . . . . . B. Desmid Distribution in Relation to Geological Features and Soil Regions . . . . . . . . . . . . . . . . 32 0- Summary of Discussion . . . . . . . . . . . . . 44 XI. Systematic Account . . . . . . . . . . . . . . . . . . 27 A. Introduction . . . . . . . . B. Key to the Genera of Michigan Desmids . . . . . . . . . . . . . . . . . . 49 C. Systematic List . . . . . . . . . . . . . . . . 53 ......53 1. Family Gonatozygonaceae . . . . 2. Family Mesotaeniaceae . . . . . . . . . . . 56 3. Family Desmidaceae . . . . . . . . . . . . . 66 XII. Bibliography . . . . . .528 XIII. Collection Data . . . . . . . . - . .537 . . . . . .542 XIV. Plates 0 o o o 0 0 ’ ' "'oan -l ,:‘|‘- ’ I!“ A“ ~‘ on . a. .".- I“. O 5“ s u ‘v. mi I . INTRODUCTION The taxonomy and ecology (as well as cytology and phy-- siology) of desmids has long afforded phycologists a wide field for research. The great range of cell architecture and ornamentation, as well as the usually "calciphobic" nature of this group of organisms has intrigued many workers from over the entire world, resulting in a very voluminous liter- ature. The State of Michigan with its great variety of aquatic habitats, as well as its variable geological and soil features, provides an excellent region for a study of the distribution and ecology of these organisms. v.4 P. I II. HISTORY OF THE STUDY OF DESMIDS IN MICHIGAN Host of the previous reports of desmids from the state have been part of general algal surveys, either of the entire state, or of some particular lake or region. Limnological surveys, systematic lists of species, and one taxonomic-eco- logical study comprise the remainder. The earliest publica- tion (Campbell 1886) includes forty-one species from the Detroit River. A similar listing of fifty-eight species was made by Pieters from Lake St. Clair in 1894. Johnson, a pro- fessor at the University of Michigan, published two lists of desmids found in the southeastern part of the state in 1894 and 1895. West and West added more distribution records from the same region in 1898. Transeau (1917) in his study on the algae of Michigan, included desmids from both upper and lower peninsulas. Nichols and Ackley (1932) were the first to dis- cuss the ecology and distribution of the desmids in the state, in addition to listing three hundred twenty five species (in- cluding previous records) , mainly from the Douglas Lake region. ACkley also described two forms of desmids from Michigan in 1929. Several limnological papers by Welch (1936a, 1936b, 1938a, 1938b) on the bog lakes of the northern lower peninsula include desmid species (some are records of Nichols and Ackley) . The desmid population of Isle Royals in Lake Superior was thoroughly covered by a series of papers by Taylor on plankton I new» ”-5.... 3 (1935), and Prescott on nonplankton (1937, 1938, 1940, 1941). Prescott also was senior author of a paper with Magnotta (1935) upon desmid collections from Marquette and Calhoun Counties. Taft included about fifty new records in 1939. Gustafson (1942) published a complete bibliography of articles on Mich- igan algae (exclusive of those concerned solely with diatoms) and also included a numerical census of the species of various taxonomic groups of algae reported previously from Michigan (of which five hundred seventy five species, varieties or forms, or about 40% were desmids). Neal (1948) in his study of the psammon of Douglas Lake, and Wade (1949) in his study of a hard-water lake of southern Michigan, have also included a few species of desmids. t“' ~ ~ng .. l \ ’g , n yr...‘ . I; ..,v Iv. ~‘: I . 'ol;: \1.‘ ..'N‘ 'I -. :-l I"‘ ‘A ~.‘ 11’ III. HISTORY AND OBJECTIVES OF PROBLEM The writer first became interested in the study of des- mids while a student at the University of Michigan Biological Station at Douglas Lake in the summer of 1946. There, as a member of a class on fresh-water algae, taught by Dr. G. W. Prescott, he had the opportunity to examine many samples of algae, collected in part from numerous bog lakes in that vicinity which contained a very rich representation of desmid species. Collections made several years later as a graduate student at Michigan State College, from bogs and acid lakes in the southern part of the state, revealed a somewhat vari- able number of desmids represented. The writer then became interested in determining whether desmids occurred in the southern part more commonly than previously indicated. Early workers (such as Johnson, Campbell, West and West) had re- ported desmids from the southeastern part of the state, and Prescott (in Prescott and Magnotta, 1935) stated that collec- tions from Winnipeg Lake (Calhoun Lake) in Calhoun County had a. very rich desmid flora, but otherwise, records from the southern part of the state were very few except for Transeau's rapart ( 1917) from Muskegon County. The contention of Nichols and Ackley (1932) that the "richest growths in both variety and Quantity" coincides with the region of the greatest bog development (Douglas Lake region) did not agree with Dr. G. W. hAlngby " ..""" ‘ I g. 0:, "‘ “vie. -".‘ " ' u. ‘- """‘~ o...‘. .. ’z. “a. ~ O.\ . “‘wnl... 3“ n’ V Prescott's observations and collections from the western up- per peninsula, and probably reflected a somewhat irregular sampling, or at least an overlooking of available habitats in that region of the state by Nichols and Ackley. It was then thought advisable also to include this region in the compari- son of the desmid flmof various regions of the state. Thus the writer in the Spring of 1949 began a study of the desmid' flora of the state with the following objectives: 1. The collection and identification of desmids from samples representative of the various physiographic regions of the state with emphasis on those regions from which reports of the desmid flora had been few in number, especially the southern lower peninsula and the western upper peninsula. 2. The use of simple field chemical tests to determine the general chemistry (pH, carbonates, bicarbonates and dissolved 002) of the water of habitats repre- sented by the collections. 3- The determination, if possible, of whether a general correlation might exist between the desmid distri- bution (both in variety and quantity) and the major physiographic regions (including geological bedrock ‘ and the major soil regions) of the state. 4. The assembling of previous records, reports and lists of desmid species from the state, with additional in- formation obtained from the writer's collections, into a unified volume. This project would include writing of systematic keys to genera and to species, as well as brief descriptive or diagnostic comments, measure- ments, and distributional (in Michigan) data for each genus and each species. The preparation of plates of illustrations of those desmids in the writer's collections which were new records for the state or new to science. Obfiv "A‘. . "WV... ’! eta, N '“i (I ‘IA.' 1.... ~. IV. GENERAL MORPHOLOGY AND CLASSIFICATION OF DESMIDS The term "desmids" is applied to certain unicellular or filamentous algae belonging to the Zygnematales, ,alarge order in the Chlorophyta. Primary characteristics of the division Chlorophyta include the presence of a thalloid structure (lack of true roots, stems and leaves), the predominance of chloro: DhYll A and B pigment over xanthophyll and carotin, food stor- 386 1n the form of starch, cellulose walls, unicellular sexual cells or sexual organs, and the possession usually of two equal flagella on motile reproductive elements. The Order Zyg- nematales (in which the desmids are included) is sharply de- fined and delimited primarily from the other orders comprising the Division Chlorophyta. by the lack of flagellated reproduc- tive cells and by the occurrence of a special type of sexual Process in which a fusion of amoeboid gametos (usually vege- tative protoplasts) is involved and which usually is spoken 01' as conjugation. The desmids (about 4000 spp.) generally °°mDrise trio or three families of this order. “'0 genera (W and Genicularia) with a total number of twenty species, the components of the Family Gonatozy- gonaceae, are often considered desmids and included with them. The other two faunas, comprising the desmids prOper, are the Mesotaeniaceae (saccoderm desmids) and the Desmidiaceae (plac- pi! 0 .,.q. 'U n D u n. u u... oderm desmids). 4l.spp.) and the latter consisting of twenty 8 The former, consisting of six genera (about -four genera (3900 spp.) compose two distinct series of forms whose relationship to one another is not completely understood. Several major characteristics that distinguish them are listed below in tabular form: 1. Cell arrangement 2. Cell shape 3- Cell wall pores Segmentation Construction Layers? 1" Formation of new cell walls af- ter cell divi- sion Mesotaeniaceae usually unicellular; (one genus with short filaments) commonly rod-shaped or oblong and with- out a median con- striction pores absent not transversely segmented layered 2 inner-cellulose outer-pectose elongation through- out the entire length of wall of daughter cells Desmidiaceae majority sdlitary; some colonial or united in long filaments variable from cy- lindrical (with rounded, truncate or attenuated ends), to flattened disciform or poly- radiate, usually with a median con- striction (sinus) partially dividing the cell into two symmetrical halves which are joined together by a con- necting zone (isth- mus pores absent transversely seg- mented layered inner-cellulose middle-cellulose and pectic com- pounds (some- times Fe) outer-pectic com- pounds regeneration of new sections of semicell walls I I m‘ I. 'h.J. ‘ O “in, i... ‘4 , Mesotaeniaceae Desmidiaceae _ 5. Behavior of proto- protoplas't's rarely pro't'opIast's usu- plasts (gametes) escape from conju- ally escape from in conjugation gation tube conjugation tube 6. Chloroplasts variable variable spiral bands 1 per semicell - parietal axial stellate 2 per semicell - axial and lateral to each other 4 or more per semi- cell - parietal 7. Nuclei single - usually single - centrally centrally located located The evolutionary position of these organisms in relation to one another and other members of the division Chloroplyta is little-understood. Several hypotheses (Fritsch 1935, e.g.) deal with evolution of the desmids in general, from forms simi- lar to certain species of the Chaetophoraceae in which motile motes lose their flagella and become amoeboid before fusion, or from forms similar to certain species of the Volvocales such as Chlagdomonas eugametos in which there is a type of °°nJugation in sexual reproduction. Other theories dealing with relation of the two groups of desmids to each other, have the more complex placoderm desmids (varied shape. constricted, thrse cell layers, without pores, etc.) evolving from the sac- coderm type (such as Mesotaenium with simple unconstricted rounded cells which possess “0 cell layers and lack pores). “nine (1950) however, believes that any of the simpler for” have evolved by reduction of the forms similar to polyradiate 8Decies belonging to the saccoderm desmids. Still other theories I“. «‘3 O t? L‘Oyfi.‘ 'H 1". 10 deal with the question of whether filamentous forms of des- mids have evolved from unicellular ancestral forms or whether the reverse is true. These various theories are thoroughly and critically discussed by Prescott (1948) and will not be further considered here . Q ‘U 0“ $ ‘ ‘ I "" ME: he": :. .3“-l I. p . ". v 11 V. THE DISTRIBUTION OF DESMIDS In general, aquatic plants, especially algae, have a much more nearly world-wide distribution than do terrestrial plants. Some species often occur on all continents, having been dis- tributed by various agencies such as wind, interconnecting bodies of water, animals and man. Desmids are distributed over the entire world except on the Antarctic continent. A certain number of species appear to be cosmopolitan (Strom (1926) believes that two-thirds are cosmopolitan), but many are components of somewhat poorly defined regional floras (such as the Arctic, African, etc.) or have a very irregular or disjunctive distribution. Ire’nee-Marie (1938) has studied the various agencies which are important in the dispersal of desmids. According to him, the principal agents responsible for dispersion in a local territory are seasonal floods, winds and animals (including insects). Aquatic birds, terrestrial insects and wind, however, appear to be more important agents in dispersal over a large region. There have been attempts also to arrange groups of species mainly on the basis of physical habitats. Thus La Porte (1931) after analyzing taxomonic lists of European desmids has listed ten types of associations. Examples include the Aerial 2210: ciation wherein species of Mesotaenium occur in moist sur- faces of soils and trees, the Subaerial association (Desmid- iacetum aeromilum) wherein a few forms live on moist, acid 9‘ ”‘ ..,. h 1.3:... h I." .4 In I. "v ‘I 12 soil around m cushions in alpine regions near melting snow, and the Closterietum commune wherein species primarily of Closterium, and many species of diatoms inhabit newly formed ditches or dripping banks. Others include the Egg- grietum transitorium, a mixture of desmid and diatoms species which inhabit slightly acid mossy bogs, and some of which are components of the previously mentioned Closterietum commune and the Emstro-Micrasterietum. This latter group is composed of eight genera of desmids associated with 9.22935. rostrata and g- M in Sphagnum bogs with a low pH of 5.0-6.0. The 9125- m-lineati-Pinnularietum-stauropterae association is a poorly defined group based on lists of species associated with 231315 rostrata and 9.3.2.9.! limosa in Swiss marshes. As assem- blage of various species, mainly of Cosmarium and Staurastrum, usually found free floating or attached to aquatic plants in the deep water of bog lakes is considered the Cosmarietum- Staurastrietum. Another poorly defined association (Desmid- iacetum-bgnticum) is the number of species of all genera found in shallow water of bogs and the benthon. The planktonic association (Micrasterias-Staurastretum-planctonicum) is com- Posed of a collection of species usually found in open water. Lastly, those species of desmids (usually of Cosmarium and Closterium) which are adapted to water on the alkaline side of neutrality, are included in the Calcophilic desmids. Al- though somewhat poorly understood, there is a corresponding change of these desmid associations with stages in the hydro- 8°°8raphic evolution of bogs and lakes . Even '33 s... w.‘ \ =IQ"'Q r A A ':-~\-. '0 “ “'J. t K I I .‘IV Iv' 13 VI. FACTORS DETERMINING THE: OCCURRENCE AND DISTRIBUTION OF DESMIDS It was previously mentioned above, that desmids as a group have a world-wide distribution. Within limited areas however, the occurrence of this group appears to be determined by eco- logical factors, primarily water chemistry. West and West, as early as (1906) attributed the distribution of desmids in the British Isles to certain geological formations. They pointed out that where lake waters overlay ancient Precambrian rock, the richest development of desmids occurred, whereas in waters overlying Carboniferous, Secondary or Tertiary geologi- cal fornations, desmid occurrence was considerably reduced. They further stated, that the abundance of individuals is cor- related with the lack of lime and the presence of humic acids. In a later paper (1909), they re-emphasize the necessity of tie factors for an abundant desmid-flora; a geological forma- tion older than the Carboniferous and an abundant rainfall, and show the correlation betwoen the abundance of desmids and the geological regions, and distribution of rainfall in Great Britain. Although not fully understanding the reason of the correlation, they suggested that a chemical analysis of the water might give the necessary information. Wesenberg-Lund (1905) agreed with the Wests in respect to the chemical fac- tors (absence of lime and presence of humic acids) but claimed 3' 14 that the antiquity of the region did not influence the abun- dance of desmids because the glaciation in many regions had completely modified the terrain of the older geological bed- rock . More recent workers are now of an agreement that the chemi cal nature of the water is the primary limiting factor in desmid distribution. Smith (1924), although agreeing that a geological correlation similar to that of the Wests has been found in his studies of the plankton in Wisconsin, Ontario and New York, admits that "the factor governing the distri- bution of desmids is not the antiquity of the lake, but the chemical nature of the water" . Strom (1926) also emphasizes the water chemistry (and its relation to geological formations) as important in algal distribution. The importance of water chemistry has further been shown in the determination of two main types of planktonic algal associations, the Caledonian with a conspicuous desmid content, and the Baltic with a rich blue-green algal content. The water chemistry which favors either the develOpment of one association or the other, is markedly different . Although the chemical content of bodies of fresh-water varies greatly, the Caledonian (desmid) type 01’ Plankton occurs where the water is low in nitrogen and Phosphorous, low in calcium and magnesium, but often relatively high in oodium and potassium, whereas the Baltic type is pre- sent in waters of higher alkalinity (with a pH of 7.2-9.8) characterized by larger amounts of calcium, magnesium, nitrogen I n :" .patn ~. View . a ‘ .. l“‘:l . . ‘H: l'. “'"1 .1; "tan '..r e \_ a. - . .‘5 I vd.‘ ‘ "In a 15 and phosphorous. Pearsall (1923, 1932) has pointed out the value of the sodium-potassium / calcium-magnesium ratio in the determination of the type of planktonic flora present in a body of water. He also presents in tabular form (1928) the correlation of plankton types with the chemical contents (hardf ness, Na-K / Ca—Mg ratio) in bodies of water from all over the world. A rich desmid flora is thus found in waters where the Na-K / Ca-Mg ratio is blh‘ Similar results have been reported by Smith (1924b), Welch (1935, 1936a, 1936b, 1938a, 1938b) and Prescott (1939, 1951) in the United States. Many other ecological factors (both climatic and edaphic) without a doubt play an important role in the presence of des- mids. Prescott (1948) questions the possibility of the pre- sence of growth-promoting or other undetermined chemical sub- stances as being of critical importance. Strom (1926) lists four essential factors determining alga-flora. They are tem- Derature, aeration, salt content (i.e. principally lime)and contaminating organic nitrogen} . Certainly, all of the com- plex factors that go to make up aquatic habitats have some bearing upon the organisms that live in those habitats. The role of light, temperature, currents, etc., in plankton pro-- duction (and thus in a deSmid production) is extremely com- plicated, and as yet is not clearly understood. Welsh (1935), Rawson (1939), Prescott (1939. 1951), and Pennak (1946) and others have all attempted to classify and discuss these fac- tors, their interrelationship and their effect upon aquatic Organisms . 16 A complete repetition of voluminous published data cannot be made here, although one can emphasize that the desmids as aquatic organisms clearly reflect the many factors of their environment with the primary determiner in occurrence (both in quality and quantity) appearing to be a chemical one as stated above. 17 VII. METHODS AND PROCEDURES In order to obtain desmid samples representative of the major physiographic regions of the state, several problems were in- volved. The general calciphobic nature of the desmids required the location of soft-water habitats. Such habitats, at least in the southern lower peninsula, it appeared from observation, were usually restricted to bog lakes. In order to locate these lakes the writer used several methods. Bog lakes are generally surrounded by some type of a vegetational mat, (Carex, Sphagnum, various members of the Ericaceae, Sarracenia (pitcher plant), Decadon (water willow) and others). Parts of such mats over a period of years, through natural change, become converted into organic peat deposits. Thus, through the location of peat deposits surrounding lakes, with the use of available county and soil maps, obtained through the courtesy of the Soil Science Department of Michigan State College, the ' writer was able to locate various bog lakes. Many of these provided excellent desmid habitats. Soil maps of some counties were not available, or were of such a general survey nature that they were of little value in locating soft-water habitats. In those counties, the writer depended upon information sup- Dlied by various persons, including staff members and students in the Botany Department of Michigan state College. Bog lakes in general are used very little by man for fishing and other h -el. \_w:. ‘V'eeav. u i ." "um-v. "-- i.... 'i'.¢- , ‘ 4 . I ' ‘ e ”at |.. a A... l "..'v I. ‘-- ‘ .A' a,“ -'_ 18 recreational purposes, and thus in many areas, eSpecially in the upper peninsula, they and other habitats (marshes and swamps) are often located in regions not accessible by road. Collections of the Open water in many bog lakes was also im- possible because of the dangerous condition of the mat. Var- ious ponds, sloughs, swamps and marshes were also sampled. In general, most collections were made from squeezings of mug, Utricularia and other plants, scrapings from culms of submerged higher aquatic plants, and by plankton tow. They were preserved in Transeau's Solution, known as 6-3-1 ( 6 parts Water, 3 parts ethyl alcohol and 1 part commercial formalin). A total of two hundred fifty or more vials of material from seventy three different stations (as shown in Map 3) were available for examination. The majority of the collections were made by the writer, but several from Berrien County were kindly furnished by Dr. M. L. Britton of Northwestern Uni- versity, Dr. G. W. Prescott also graciously made available the use of his extensive collections from Northern Michigan. The methods of chemical water analysis for pH, methyl-orange alkalinity and dissolved 002, which were performed in the field, are given in Theroux, Eldridge and Mailman (1943) - EX- amination of the material was made in the laboratory. Species determined for each collection were listed on a collection card. In addition, a separate card record for each species "618 maintained in order that distribution data for that species \ 19 could be assembled. A drawing of at least one specimen each of the majority of Species identified by the writer was made with the use of a camera lucida. 20 VIII. GENERAL PHYSIOGRAPHY OF MICHIGAN“ The state of Michigan has been divided into a number of physiographic regions (See Map l). The upper peninsula is divided into such regions, a western and an eastern, the boundary being near the meridian passing through Marquette. The western uplands is an uplifted peneplain, averaging 1600- 1800 feet above sea level (1000-1200 feet above Lake Superior) with the local relief, which is not more than 500 feet, aver- aging 100-300 feet. The precambrian bedrock which is composed of igneous material such as granites, gneisses, schists or metamorphic sedimentary rocks of quartzite, dolomite, slate, etc., is irregularly covered in about three-fourths of the region by glacial drift composed of Palezoic sandstone, shale and limestone. The main areas where the bedrock occurs (as hills, rock, knobsand, sharp ridges) above or near the surface include (as shown in Map 1) regions of the Keweenaw Peninsula, the Huron and Porcupine Mountains, the Gogebic range between Ironwood and Lake Gogebic, and the extreme southern portion of the western peninsula near Iron Mountain. Other areas occur in the vicinity of the towns Republic and Crystal Falls, and in the Marquette-Ishpeming region. The surface drainage of this region, which is controlled both by glacial formations and pre- glacial topography, is into Lake Superior and Lake Michigan except for a small area in 'southern region of Gogebic County * Ada~I>ted from Leverett 1917 and Scott 1921 ..\. 5‘ m-“ MAP 1 PEYSIOORAPHIC REGIONS Outcrops or Bedrock Near Surface - Proterozoic—Igneous or Metamorphic Rock 2%7é Paleozoic-Calciferous Sandstone or Niagara Limestone m Paleozoic sandstone Adapted from: Leverett (1?17) Scott (1921 x° ........ UPLAND 5: o “a ‘e , i e i i \. ‘jlolhnsnaICl‘ v a 1 Cnnca ,r. A... - -,_ Gram: I a'“"" hour.- 1 I I * ~-v~>- "f *"L ' i ’V * ‘*‘* * Mac " e wu-vara \‘ gini-ustxr'or'rprr . ma. 1H,; I I Dds—lar! ,LJ / "II-2e; ' :".~'V“. ..... 3, I I I I I ‘ q — - ~ try - r , , e , e v 0 a a w- n: Me 'a wan-x v. u I: 3nd I I k MICHIGAN ‘SAGINAW ' ' ‘ 1, D I ,.LOWLAND c 1 m I I . ._ _ _ L i ‘ i: ’r Tn: ‘ 1 ‘ r r I ' r 9 .ur I - L I ~. 7 a , , Own... 3 qnfieh I I I ‘ I , . I I I I I I V D ‘ , T 4 {Jo—IIund Mo _____ .1 _...l,. .i,_ ,._-,. , i A, V I AII-qan v u, Envor yInq'mrn TIL:IN9!|oni I I , l ‘ ' I I ! UPLAND ! . ....... .1—.$_.Y.--«L._—1-L»«—— 7--.- 1.-._.___ Von an In -KO|UFI [Ou‘ olV'Ou'V JOC‘QO" lWOIH'Iha' ‘WOy'V. \\\\ I . I I ' I I ' fifi - .I. ....... 4 ..... 4 .r._.Li_,-—, . {tau .5, 4a: nyarancn iktnauuu I - . . . I l I . ' 1 I ‘g . A I : c;.. .m _.-{’J .I.. ’Ofi Ia" §.' IS“ h'.‘ a], 'M £—" 21 which is drained by the Wisconsin River into the Mississippi River. Drainage is incomplete in many morainic areas, re- sulting in numerous small lakes and swamps. The Eastern Low- lands occupies primarily that region of the upper peninsula eastward from the meridian passing through Marquette. Exten- Sions also occur southward into Wisconsin and Minnesota as well as northward and westward in a narrow coastal strip along the edge of the Western Highlands. Generally this region is 1000 feet lower than the Western Highlands, averaging about tits hundred fifty feet above the Great Lakes. The unequal weathering of the younger Paleozoic bedrocks has resulted in what has been termed a belted lowland, with some formations in tablelands and others in low areas between the tablelands. Taro examples are the Niagara limestone formation along the northern border of Lake Michigan and Lake Huron, and the cal- ciferous Cambrian sandstone tableland overlooking Lake Superior or the plain below it in Alger and Marquette Counties. Most of the region is irregularly covered with a glacial drift that is very variable in its composition and its depth. The table-- land of Niagara limestone along the southern boundary is the most thinly covered. In addition to the long moraine at the Junction ofhackinac, Luee and Schoolcraft Counties, the other notable physiographic features are the swampy, sandy plains, the two major ones occupying much of the drainage basins of the hanistique and the Tahquamenon Rivers . ' The former drains some 1400 square miles of territory in the western part, whereas 22 in the central part, the drainage takes place by the Tahqua- menon River to the north and the Carp River to the south. The drainage of the eastern part is mostly into St. Mary's River and Lake Huron. Despite these extensive river systems mentioned, the drainage is relatively poor with large areas covered by swamps and lakes . The altitude of the southern lower peninsula compares more favorably with that of the eastern than with the western upper peninsula. The average elevation is about 800 feet above sea level, with about 96% of this region below 1200 feet. The main physiographic regions (as shown on Map I), are the Erie lowland, the Thumb upland, the Michigan lowland, the Saginaw lowland and Northern upland. Both the Thumb upland, which extends in a northeasterly direction from Hillsdale County to the Thumb and the Northern upland which is composed primarily of 1500 square miles largely in Crawford, Otsego, Wexford, Os- ceola and Missaukee Counties, constitutes the regions of hizhest elevation. The former ranges from 1100 feet in Hills- dale County to about 700 feet at the end of the Thumb area, whereas the Northern upland is about 1200 feet in elevation. The bedrock in this area is primarily of Paleozoic age, with Upper Silurian, Devonian and Carboniferous deposits of limestone, shale and sandstone arranged in a nearly horizontal position but dipping slightly to the center of the peninsula. Except for outcrops of thinly covered areas of Marshall sand- . a.- ‘ I c , ‘ . . ‘ n . ,. I ' . . a . ' ‘ I . t V- I I r o. o . I I . . _ . ‘ { ‘ h l a- ‘ - e i - 0 fl . I In ‘ . a . . , . ,. . ’ ' k L Q " ' 0 " “’- " C lines a. vo. ‘ I ‘II .’ new, I . ~‘ tion. in I l - ”mg q, a“... w. .5. _ . . s .'; ‘r .k". we“ ‘.\c a}; a” " 'aov -" nu ’ 4 "' a! It ’1 ItI V I. x“ in. i . ll ;." :‘Lvl Can... 'u. ., 'G ‘ H a“. ‘ 9 .. u . 'I- u- 1 no... u“ Q T t; '\ F. ‘. H4 ..v 23 stone of early Carboniferous Age in parts of Hillsdale, Jackson and Calhoun Counties and Palezoic deposits of limestone in Presque Isle County, the southern peninsula is covered with glacial drift of variable depth and composition. Leverett (1917) states that there are areas near the border of Lake Michigan where the drift is known to exceed six hundred feet, although the average depth is about three hundred feet. The drainage of this region is determined chiefly by the physiography of the different areas within it. In general, the sources of most of the major streams (which empty into either Lake Michigan or Lake Huron) are found in the upland areas. In the Northern uplands (as shown in Map l) arise the headwaters of the Muskegon, Manistee, Au Sable and Cheboygan Rivers. The Thumb upland is the source of tributaries (such as Huron River) to Lake St. Clair and Lake Erie. In the Southern upland near Hillsdale and Jackson Counties, are lo- cated the sources of three major streams, the St. Joseph, the Kalamazoo and the Grand, which drain also part of the Michigan lowland before flowing into Lake Michigan. The Saginaw River and its tributaries which constitutes the largest river sys- tem in Michigan, drains the major portion of the Saginaw low- lands, although one branch arises in Southern upland and another in the Northern upland. The Grand River also drains Part of the Saginaw lowland- According to Scott (1921), the great number of lakes, both large and small, especially in the northern and southern interlobate areas, and in the mor- 21+ ainic regions within Calhoun, Barry and Kent Counties, is in- dicative of the incompleteness of the drainage. ,. t- on, u . ." 'p D '01:. . U )0 25 IX. SOIL REGIONS OF MICHIGAN The wide range of soils of Michigan have a close re- lation to the surface formations of glacial origin. Veatch (1937), discusses the general relationship of geological form- ations to soil, but emphasizes that other factors such as the lithological character of the drift, the age of the land sur- face, details of relief or topography, the climate and the vegetative cover, must be considered as well as the soil- forming processes in the differentiation of soil types. He further presents a map of Michigan (which is reproduced here as Map 2) showing the various divisions based on the litho- logic composition of the surface deposits. The great diver- sity of soils (and thus also of the surface drift) is even more apparent when one observes the sixty-seven natural land divisions discussed, and also shown in map form by Millar (Michigan State College Extension Bulletin 290). Even smaller subdivisions of the natural land divisions are discussed by Veatch (19141) in reference to the characteristics of individual soil types, and their land character, agricultural value and use, and to their distribution in Michigan. Because of the enormous variety of soil types thus exhibited in Michigan, and because they have been thoroughly described and discussed by the authors mentioned above, no attempt will be made here to discuss them individually- A summary of the maJor land NI. !.:VV’ In,“ ‘I ‘I I ’h “d ag- I“ 26 types, hdwever, which are found within the state (Veatch, 1941) can be briefly mentioned. 1. 3. The lake bed claygplains type, representing old lake beds formed during the high or glacial stages of the present Great Lakes, occupy primarily level or flat regions, underlain by clay or silt, along the shores of the Great Lakes. There are very few lakes or peat swamps in the land division. The rolling_clay_p1ainstypg, represent a somewhat diverse group of gently rolling lands occupying till plains or ground moraines, similar in some respects to the type mentioned above, but with a greater range of difference in local elevation, and with a greater proportion of well-drained soils and asso- ciated peat and muck land. The gay sandygplains type, which covers the largest area of the state, is composed of five subtypes. They include level and pitted plains associated with. numerous lakes, peat and muck land in several coun- ties (Kalamazoo, Jackson, Oakland, etc.) in the southern part of the state, dry sandy pine and oak plains in both the northern part and southern part of the peninsula, dry gravelly and sandy hardwood plains and valleys in the northern part of the state, valley plains associated.with ridges and rock knobs in highly elevated parts of the western upper penin- a g _ ‘ v . . . I . ' o I o . u l ' J v A . I I . ' 9 ., i . ' O e u . . , . ‘ , . , ~ _ . o . . . I l _ . . _ e ‘ ' a o a ' I ‘3 I I i A O . , . a . . . . . V . 27 sula, and the dark-colored prairie lands of the southwestern part of the state. The sangyghills land typp, represents hilly, sandy uplands which arise above clay plains and sand plains. Irregular topographic features such as knobs, basins, sharp ridges and broad long slopes as well as numer- ous lakes, are characteristic of this type which is represented by subtypes in hilly regions of Barry, Jackson and Washtenaw Counties, pine and oak hills in Newaygo, Roscommon, Oscodao Counties, etc., and sandy hardwood hills of the northern part of the state. The wet sandy plains typg, represents wet, water- , logged and hard pan sands associated with flat areas or low, narrow, linear ridges of dry sands, occupying areas on old lake-bed plains. Variable amounts of peat, muck and wet clay land as well as clay plains are associated with this type in parts of Ottawa, Muskegon, Saginaw and Tuscola Counties. The sandy plateau gypg, is represented by level, sandy plateau highlands which are cut by broad deep valleys at wide intervals. Slopes of such highlands may be sharp escarpments; valley slopes with'broken topography or a succession of separate terraces or benches. Areas represented by this type occur in high sandy hardwood hill regions of some northern 28 lower peninsula counties (Antrim, Charlevoix, Emmet, etc.). One subtype represented by level, dry, sandy pine plains occurs in the plateau south of Newberry in Luce County, while another subtype composed of high bench land borders Keweenaw Bay and Lake Superior in Baraga, Houghton and Keweenaw Counties. Rock plains type, is represented by level or gently rolling plains, plateaus or benches where bedrock lies very close to the surface. Only a few streams and lakes, but often numerous swamps, are associated with the numerous stones, slabs of bedrock, and boulders that are characteristic of this type. The subtypes are classified on the type of underlying rock and vegetation-soil relationship. One subtype comprises limestone-underlain regions with forests of sugar maple, beech, elm and basswood as well as a large proportion of conifers in the eastern upper peninsula (Delta, Alger, Schoolcraft, Mackinac Coun- ties). One other subtype includes the sandstone . plateaus and benches principally along Lake Superior in Alger County, forested by balsam, fir, spruce, ‘ cedar, hemlock, aspen and white birch. The land underlain by slates and crystalline rocks, and asso- ciated with a large proportion of wet land in shallow swales or held in hollows in bedrock and occurring in high elevated regions of the western upper 10. 29 peninsula (Baraga, Marquette, Iron, Gogebic Counties) comprise the third subtype. A mixed forest of sugar maple, yellow birch, balsam, fir, spruce, etc., densely cover this latter region. Rock knob typg, is represented by areas in the Huron mountains and the northern part of Marquette County, Porcupine Mountains, Copper Range from.0ntanagon County through the Keweenaw Peninsula as well as smaller areas near Ishpeming, Iron Mountain, Crystal Falls, Republic and Ironwood. Here the land is char-~ acterized by rugged topography with rock outcrops of domes, knobs or cliffs and coarse drift in the valleys. Swamps, bogs and streams are numerous. The swapp plain typp, comprises large extensive areas of wet peat and muck land located in: the Tahqua- menon River drainage region of Luce County; marsh and forested swamps near Seney in Schoolcraft County, and swampland in lections of Menominee, Marquette and Delta Counties. ’ The lake shore typg, is represented by narrow bands of land occupied by dunes, wave washed beaches and floors of bedrock, parallel sand ridges with inter- vening swampy depressions and lakes, marshes and sluggish streams which border the Great Lakes. Prin- cipal areas are located in the various counties of the western lower peninsula bordering Lake‘Michigan ., . ’ , ‘ . . ' x . I ' . ‘ ,I ‘ l . . . A . I . I ‘ O ‘ . , . y _ _ .. , . I 7 . . . i r . . ‘ . . . . I l ‘ ’ . .0 ‘ ‘ . I . l . . , ‘ ‘ \ . - , . . I ' A r . - . . ’ I ‘ | A. . _ . “I . . A r .v. I . . ‘ v ' 7‘ ‘ ‘ I l ' I . . ' 7 I . .‘ I‘ . , . V r V . a ‘ A . o ' ' t \ I . . I ‘ I l A . ' . . ‘1. ‘ ' ‘. l t n- .- ‘ . ' . I ‘ ) . ~ ‘ . I ‘ . e ~ . . I I . r r -- ~ - . . " . . I, .. ' I ' A p I . . . , J. ' ‘ H r ’ K J r 4 . I. v I h (A 30 and near Grand.Mara1s (Alger County), Deer Park (Luce County), as well as several places upon the Lake Michigan shore between St. Ignace and Manistique in the upper peninsula. ‘\ "In 't 's 1.4 uI.‘ .5 VI 31 X. DISCUSSION AND RESULTS A. General Data The collections from seventy-three habitats (as shown on NMp 3) yielded over two thousand determinations of which about shyn;hundred were from the southern lower peninsula, three kmndred from the northern lower peninsula, four hundred from unreastern upper peninsula, and about five hundred from the western upper peninsula. Records for individual Species, variety or forms are located in the systematic section of this Imper, and will not be discussed here. However, aggregate statistics are listed below. New species, varieties or forms 19 New records for the state 192 Previously reported but also found by the writer 343 Previously reported but not found by the writer lg§. Total species, varieties and forms in the state 752 The distribution of the seven hundred fifty two Species, varieties or forms (including previous reports) in the vari- mnsxegions of the state are as follows: Southern lower peninsula (below Bay City to Ludington line) #15 Northern lower peninsula 425 Eastern upper peninsula (east of Marquette and Menominee Counties) 280 Western upper peninsula ' 241 Isle Royale 191 .2 l O O jlc'cunu . I Lo..._.-.. 1: '5'004 0 , ‘ 1 fr. , - “UH.“ gouge, , Lvnqle w‘c L , . , , w , Jugs Mcm'v'ovcncy‘ A perm MAP 3 COLLECTION STATIONS , «ovum-c \ [VG-")Vfl Grand 5 " no..." 0 O 1 ‘ ‘M‘xlcale! p \vr,-m..F f _.l . Dollar") . O » O ’ D 0 y r 4 x O i L ,-,-._Y ,.,>."__1 T H mm,” ‘ . ,gv , 9 I _______ 1_.4 —’-.- _.A. _..,L_i_ i_._.l~_ Von awn »Ko\umazoo Cum” mason gang“). M. e y r \ v . O. 0,0. 1 ‘ C l , ‘ ‘ ‘ O O ‘ I 1 1 I 'umgcum D v \ 1 ' ‘ I . I . . ‘ ,__ _,.___. iL.J——_L, S! dot-ph'Bvonu no“. Ivomo. '...\_.._._._. ' . . I h I. "' 'u' .‘ 'A’ ' in 3's. an...‘ . KAT 3‘4 ‘ 32 Although the numbers of determinations of species made by the writer are unequal from the respective four major re- gions of the state, such determinations were made from col- lections of widely spaced stations in the state and thus must be considered as representative of the state-wide distribution of desmids. No claim is made that the entire state has been completely covered, but it is thought by the writer that the data from his widespread collections give a more accurate representation of certain regions of the state, such as the Southern lower peninsula and Western upper peninsula, than has been known previously. Many counties still lack a re- port of single desmid from within their boundaries, but the location of satisfactory habitats, chance collections, and the enormous number of aquatic habitats to be sampled, all Provide difficulty in obtaining equal representative samples or every county in the state. B. Desmid Distribution in Relation to Geological Features and Soil Types In attempting to determine whether a general correlation m18111: exist between the abundance of desmids and the geologi- cal and soil characteristics of the major physiographic ”$10113, one is confronted with many factors that must be considered. It is an accepted fact, that desmids are generally cal- °1Ph°bic. and thus occur most abundantly in soft-water habitats. The Question that then arises, is whether previous distribution I'ecords necessarily reflect the relative number of such habi- EIQ- ‘. ' ':«ce. :1 c ‘. o... .1. ..‘- Q' .. . .j ,, ‘. “- '- 33 tats (or abundance of desmids) in the various regions of the state. The writer believes that the answer must be in the negative, because the concentration of the majority of pre- vious investigations have been primarily directed toward two centers; the Douglas Lake region (Nichols and Ackley 1932, Taft 1939) and Isle Royals (Taylor 1935b, Prescott 1937, 1938, 19%, 1941) . The large number of species reported from these two centers certainly reflect the fact that desmids are abun- dant in these two regions, but obviously cannot be used for comparison with other regions where desmid reports are few despite the fact that numerous soft-water habitats are pre- sent in many cases. The possession of a considerable number of additional distribution records from not only the writer's collections, but from other reports since 1932, perhaps gives a much more complete picture than available to Nichols and Ackley, but still does not completely represent necessarily the relative abundance of desmid habitats (and thus desmid abundance) in the various regions of the state. Another fac- tor that must be considered when discussing correlations be- tween physiographic regions and the abundance of desmids in those regions, is that soft-water habitats although generally favorable for desmid growth, do not always show equal abundance of desmids. Although desmid abundance appears correlated with the abundance of soft-water habitats, there is great variation in the number and kinds of species present in individual soft- water habitats. Certain regions of the state may have a "42‘3‘ :‘1 kivcd'. ‘- w ‘1.." ‘Fc- D \ ”'VOOUIV Q=~1.F: "k-Juu 0 d e "a ”5' - 4 “”‘iv... p g u “-1.- . . . 00""~ ‘a. u I '1." ”re- ‘ in h... u ' itlnba u.__" ‘v.“. a VI ~‘h:. I": v. . M.“ ‘ .‘V-Iu. h‘ vf' AA‘ .. “' 'I. , u 34 greater abundance of desmid habitats, but by no means is the distribution or abundance of desmids uniform throughout these regions. Thus, such local variation may have had an important influence upon our present distribution records, thereby modi— fying any broad general correlation to some degree. This is even more apparent if one refers to Welch (1935), Rawson (1939), Prescott (1939, 1951) and Pennak (1946) who discuss the great number of complexly inter-related edaphic and climatic factors which operate in producing an aquatic habitat. If only the chemistry of the water is considered as the primary factor in controlling desmid distribution, there remains a very complex problem. Unfortunately chemical analysis of the Na-K / Ca-Mg ratio (which has been discussed previously as important in desmid distribution) for various desmid habitats in Michigan are not available except as comparable chemical data for a few bog lakes in the northern lower peninsula, (Jewell and Brown 1929). The use of available but much simpler chemical data (such as pH and methyl-orange alkalinity) of soft-water habitats, creates other objections. Such simple chemical analyses are not only mere indices of a general nature, but also do they reflect only the value for that sample of water at the time it was determined (it being known (Welch 1935) that pH and other chemical components may change daily as well as seasonally). Collections of algae are likewise only representative of the time of collection, and in the immediate area of collection, and do not reflect either a total seasonal ':l."“ Pl ’0'!“ V Hggzub 1 "urn“! - . l , no t ‘ i:- .' 'VOQ‘V .,F‘A" "r a... v - «v A “ 44.6 V \ Ea. p i a My v.‘ .‘A.‘ e 1.,‘1ha. N‘."; w. ‘ in c.‘ G". a.. v. " m. M. Ho}; «hi 0 (I, I h I: i‘ I Q. I ‘II I.“ a dip 35 picture of species present or the total number of species present in an entire pond, lake or ditch or whatever habitat is collected. Thus the number of samples, the number of habi- tats in one station, the time of sampling, as well as the thoroughness and accuracy of examination, also create variables. If one can assume, however, that one can compare the simple chemical (pH, methyl-orange of various soft-water habitats) indices taken during the day in the summer months with the number of species of desmids found in the collection obtained in those soft-water habitats at the same time and place, we will find noticeable contrasts. Listed below are the pH and methyleorange alkalinity determinations as well as the number of species determined in those samples from a number of sta- tions selected at random. Bicarbonate Acidity (in terms No. species pH (p.p.m.) of CaCO3 p.p.m.) of desmids #65 5.5 9 23 ‘ . 10 #67 6.0 11 ~ 5. 94 #68 5.8 15 6 5o #70 5.9 18 20 7o #72 5.6 25 ' 6o , 4 Thus it is apparent from these few stations, that although desmids occur in soft-water habitats with similar pH and methyl- orange alkalinity values, they occur in much greater abundance in some of these habitats than others. Even in a single lake, the habitats may be so different that the desmid representation a. ‘ , \ ".""C I. inflow-v . o . " I; 3..., new .V‘. 1;.» '1.‘ ' out“ '0 e" ‘ . u u‘ a In. I I r..\‘ In. “H." d 1 “I”. . . n . :oe‘.‘ I. up - . ‘ 'N . I .4 . qt‘y‘ ! O . . #5: n . y‘.'. '- II" ‘V v” 36 is changed considerably. Collections from an unnamed bog lake four miles south and east of Howell in Livingston County, were made in August and October. Collections made from £133;- cularia sp. squeezings in the open water contained about the same number of species (30-35) as squeezings from Sphagnum sp. in the mat, but the majority of species in one habitat were not present in otherhabitat. That this difference is probably attributable to species preference, not only for certain types of physical habitats, but also for different chemical factors, can be shown by data collected from an unnamed bog lake near Quimby Road in Barry County. Here the Sphagnum mat not only offered a different physical habitat, but also a sharply dif- ferent chemical one from the open water. Species Bicarbonates Acidity (in terms C02 Number pH (p.p.m.) of CaCO3 p.p.m.) (p.p.m.) Sphagnum 25 4 .2 12 54 42 Mat Open 60 6 . 7 30 6 4 Water Not only was the species number much greater in the open water, but also the-kinds of species was sharply different. Strom (1926) also found a great difference in numbers of species in various habitats in Norway, and states that acid bogs contain 8 far richer desmid population than any other type 01' habitat, but are most abundant in those moderately aerated with a re- action approaching the neutral. It thus appears very obvious that many variables do exist and that only certain broad gen- g‘e‘rIGJ a: .Ofifihvofltd I'll ‘5‘ F ="e' ..Gbl 31:.‘:'_,_. “"eoud ‘ l "5 "‘1. Nu ic... ‘2 M. wu.J of. I 1' I 5"“ ~- '\J Jr b.‘ I M,‘ ID 31 37 eralities can be discussed, with the full knowledge that many exceptions probably do exist. Correlations between desmid distribution and the geological and soil characteristics of the various physiographic regions of the state must therefore be only of a general nature. Such correlations, must of neces- sity, be based upon the following sources of information: 1. The present available reports of desmids from Michigan. 2. The results of similar studies in other states and countries. 3. The very meager chemical data of the waters of Michigan. 4. The understanding of at least the major physiographic or soil regions of the state and their relationship to desmid distribution in the state. With such considerations understood, one can proceed to a discussion of the desmid distribution in the state of Michigan. Desmids, as previously mentioned, are calciphobic and therefore should have. their greatest abundance in those regions of the state where there are the most suitable habitats (soft- water). or the many factors that influence the creation of such habitats, the geological bedrock has been considered of Paramount importance by several investigators. As previously mentioned, west (1906, 1909) found the greatest abundance of desmids in bodies of overlying prepaleozoic igneous bedrock (Which is low in limestone and thus theoretically determines - the low calcium content of the waters). Smith (1924b) in zonal F) Ulimowu V ":‘-e a 'DI-ab if we ‘VU-o. a", I I. A h .-.;: “ its! '1’ - ; ‘4. :31. t‘- 1. .3“ a: )5 ‘1 ‘~ 38 studies of lakes in Wisconsin, Ontario and New York, also claims a correlation between the type of bedrock and the richness of desmids, the pre-Paleozoic igneous rock favoring (by ex- erting an effect on the chemical composition of the drainage water) the production of soft-water habitats and a corresponding abundance of desmids, whereas the younger Paleozoic deposits of sandstone and limestone favor the development of more alka- line lake water with a corresponding decrease in desmids. Strom (1926), in his work on the Norwegian mountain algae, has greatly enlarged upon the conclusions of the Wests, but em- phasizes it is not the age of the bedrock, but the effect of the bedrock on the chemistry of the water. If we apply such a criterion to the state of Michigan, we find (Map 1), that although the western upper peninsula is underlain by older and mostly lime-poor pre-Daleozoic forma- tions, and the rest of the state, by younger and mostly lime- rich Paleozoic formations, there is only a relatively small . area in which the bedrock is exposed as outcrops or present near the surface. It is thus obvious that the bedrock (whether Dre-Paleozoic or Paleozoic), can influence the chemistry of _~. surface waters only .in this small area, whereas the nature of the glacial drift which covers the vast majority of the state must have a much more influential role in determining water- Chemistry (and thus desmid habitats) in the state. Nichols and Ackley (1931) have stated essentially the same conclusion, although they were interested only in the influence of the u , _ “‘neq ., w , “in. 7". o ‘m. 4 . — lei. u“... .:VFAL ‘_ "BOU . y Jew ‘t V”. ‘ l‘~' ‘ . I. 1“ ‘o‘ 39 bedrock. The influence of glacial drift and soils developed from the driftdn the determination of surface water chemistry, cannot be fully analyzed here, although the writer believes that in general it plays a vital part. Brown (1930) at least states that “the abundance of desmids in the coastal plain (southeastern Atlantic) seems to correlate well with the wide distribution of acid sand and clay soils". McInteer ( 1938) reports similarly that there is a greater desmid abundance (numbers of species) in the regions of more acid soils (with lower total phosphorous) in Kentucky. Shoup (1947) states that the waters of various regions of Tennessee reflect the influence of the various geological strata underlying the various regions (and the influence of the soil, the writer believes, which have for the most part been derived from the bedrock in that state). Strom (1926), also states that "in smaller bodies of water, especially, it is not exclusively the underground which determines the reaction of the water, but also the respiration and assimilation of plants and ani- mals, as well as the aeration or stagnation, and last but not least, the qualities of the soil proper". It thus may be in- ferred that the nature of the exposed bedrock, the glacial drift and the soils derived from both, collectively exercise some general influence over the water chemistry of the vari- ous regions of Michigal’h Previous mention has been made in the section on soils, of not only the great variability in the depth, but also in no the composition of the glacial drift. The comparison of the sixty seven individual natural land divisiom listed by Millar (Michigan State College Extension Bulletin 290) with the des- mids reported from these divisions, appears to be a too com- plicated and unnecessary undertaking. However, the use of Veatch's (1937) eight divisions of the state, which are classi- fied upon the basis of the lithologic compositiondf the surface deposits (thus combining not only the drift but also the bedrock at or near the surface), appears to be sufficiently simplified so that general comparisons can be made. The rela- tive influence of limestone which is included for each division, would also seem to be of practical value in the comparison of desmid distribution in the different regions. Veatch's lithologic divisions of the state do not conform to county boundaries, so that in many instances previous county records are not sufficient enough information to determine from which lithologic division the individual species have been reported. It is thus necessary to use only the distri- butional records obtained by the writer for purposes of com- parison. . Lithologic Division Number of Desmid Species (See Map-2) 1 177 2 381 3 —-- 4 340 939‘}. H.'.. “a I* a '.J . ([1 ‘eo - “v. G n “"I ' V. .- H‘V‘. ‘J. 41 Lithologic Division Number of Desmid Species (See Map 2) 5 260 6 278 7 506 8 10 No collections were made from division three and only a very few from section eight, so that a strict comparison can;- not be made in these two regions. Consideration must also be given for the fact that the number of samples as well as the number of stations were somewhat unequal in the different reg- ions. The numerous other variables that may enter into such a comparison have also been previously discussed. If, however, an examination is made upon the basis of the available dis- tribution records of species 'as well as observations made by the writer, the following general comparison can be made. Division 1 (see Map 2) which exhibits the greatest lime- stone influence (and which has numerous limestone outcrops in certain regions) has the smallest number of species represented. Division 7 which has the least limestone influence (with num- erous outcrOps if igneous rock in certain areas) has the lar- Best number of species represented. This information thus largely corroborates Prescott's (1951) views on the greater desmid distribution in the western upper peninsula with a cor- responding decrease in the eastern upper peninsula. Although bog lakes are present in the eastern upper peninsula, the des- 3‘.‘ \,\ \;\\;\ \-\ \:\ \....-\ F: \ ._.\ GEOLOGIC-PEDOLOGIC RELATIONSHIPS 2% Imam] “"1 Dy )0 thvcu , 7,, minim" .g; 2 4...... '3III...IhIIlIIiiifli‘fiffli’“ .. ._,,. L "J", “I 41”.! 1]“ "Wu" ("'"ml' ”Manta-1|" exhibits strongest limestone influ uence. .muu . , _ . Emu" dam am e 93373:; wreath-'1“, as}. 'E?~ 2‘ _-_l. depths; bou IA. red tuned “Immune and .— =E_ =1"... more 18. mixed .nndnon : E= =4” Wino *Emm=u! -— _=== "A u ‘ a: . —. Hammad-song Moe-”1:5 silo moderate sharia“. and llm -—-— : w; to ”course texture; bedrock,“ ’ shells-hr Igacomm Bad. diversity at rock influence. with are to WWMHW. 3A. mlnlmum une- cubes-influence. 38 .chocolnem ondorpuered 1':ng MW louu Monsanto-col red Indred northern pen, (ml diver-n of 51'. i“; .I nets with Ii” to moderate limestone and I le Mme-.0 eeolot Influence of shale . . \ ‘ MW. 1! choeom x “Marlon nm Manne- at °a3uu4 chosen" .. '33.?“ :~\\' ‘0 ll“. m. In“ M as \ ’c‘ \_ . N.‘ ' Wflii’u “\‘g \'\ Nana. a “nun: m& 2.,“ IIIIIII n-as‘wg-miAisW-sw I": s§§s sass \ ntM-uedorhdrmyey am monl measly ‘25 ;:' fizfi'zflvw‘ \\ \ pa. d X‘ ‘m_ ' $24! \ Q X . \ ss awammisim sax \Sis: \\ ‘\ Mai-m. .lmny: undatonenndcrynuune .‘ ‘1 E smash. swarms-i :2: i\\\ \x . \s \\ s. 74% man“ w... “my.” “mam mfimg :10 mm "7.“: ti mom _. toMonuCounl pm] I an in lilo“: flood Nan mmhwmndgm “mam. “linden-chm tun-cl: em era In: Inw r3 "An: If anon-0" fi‘ "1‘ a A"! '- “ "I’ Ive-ca. ’w ‘yl": .1. a - .I “I'V‘l I'un“a a“ n-.‘.' ‘0: '. ‘e; v“ I "0}. l.‘- t n." ’.-era a .l .“c.‘ I Ive.....‘ I. u '- N“'1ov ”we .\' 'v'n. c ’ '| .1“ H 'Ov.. . :an .«L: .. 42 mid flora is usually less productive in a number of species than comparable stations in the western upper peninsula. A few habitats in this region were exceptions to the general picture and exhibited a moderately rich population of desmids. Strom (1926) reports similar findings in the Norwegian moun- tain algae, and states that "in the lime-rich districts they (desmids) only occur in any real qualitative abundance in the localities which are more or less self-contained, and directly influenced by the geologic strata, i.e., in the acid peaty bogs, though they are never so richly represented there as in clear waters". The other lithologic regions of the state are represented by a somewhat variable number of species records. Division 2 which has a strong sandstone but only a moderate limestone and shale influence is represented by the second largest number (381) of species varieties and forms. Divi- sion 4 (not including 411.,- 4B which were not sampled because of the apparently few bog lakes) which has a strong to mod- erate limestone influence, is represented also by a fairly high number of species (340) . The writer believes, however, that the high numbers of species represented in the latter two divisions are not true indications of the general litho- logic characteristics of the divisions. Rather, they reflect mainly the reports from a very few rich desmid habitats located in a generally desmid-poor region. Observations of the hum- erous collections made from portions of these divisions by the writer, reveal that although bog lakes occur in these Hr" Q. .0 u '. ' ‘ '0‘... U ",‘D‘. A ”fitn- 1 V .“:" An— in _ in.‘ "_ ' I '5 43 generally hard-water regions, the vast majority are generally poor, in desmid species. Division 5 has a strong to weak in- fluence of limestone. In division 5A, however, the dominant sandy deposits have a minimum influence from limestone. This division, although represented by only two hundred sixty species from the writer's collections, (because of the concen- tration of previous investigations in this region, the writer made only a few collections) should probably have a much higher number because of the frequency of acid bogs at least, in the Douglas Lake region. The vast majority of species re- ported by Nichols and Ackley (1932) and Taft (1939) from Cheboygan County, have probably come from this region, al- though about half the county is in Division 1 (strong lime- stone influence). It is impossible, however, to distinguish from what portion of the county the species records were made. General observations made by the writer (as a student in Doug---- las Lake region for two summers) may be used to substantiate the fact that many rich desmid habitats do exist in this region. Division 6 possesses a dominant sandy drift with slight lime- stone influence, and occurs in the northern half of the eastern uDper peninsula, although the extreme eastern portion has more calcareous material. A fairly strong representation of desmid species (278) in this region is generally correlated With the large peat deposits, swamp and marsh land areas in Schoolcraft, Luce and West Chippewa Counties. 44 C. Summary of Discussion 1. The general distribution of desmids in the state of Michigan is determined largely by the presence of soft- water habitats. 2. The abundance and distribution of soft-water habitats (and thus abundance and distribution of desmids) is de- termined in general by several primary factors. They are: a. Nature and distribution of geological bed- rock. Drainage water from lime-poor formations (such as pre-Paleozoic deposits in regions of the western upper peninsula) appear to prbduce more favorable habitats (more acid habitats), whereas drainage water derived from more cal- careous formations (such as Palezoic deposits in sections of the eastern upper peninsula) ap- pear to produce less favorable habitats (more alkaline habitats). However, this factor of geological bedrock influences the presence of suitable habitats only in the relatively small areas of the state where bedrock occurs near the surface or as outcrops. b. Nature and distribution of glacial drift. Waters draining acid sands and clay soils are more favorable for desmid production (more acid) than water draining soils with high cal- careous content. This factor of glacial drift 45 appears to be more important in influencing desmid distribution in the state than geologi- cal bedrock because the vast majority of the bedrock in the state is covered by glacial drift. c. Local habitat characteristics. Many factors such as type of drainage, physiographic features, vegetation, accumulation of organic remains of plants as well as the numerous climatic and edaphic features that influence aquatic habi- tats may so operate as to provide favorable desmid habitats in an otherwise unfavorable region. A 3. Desmids are widely distributed over the state, but are more abundant in certain regions where there are more suitable habitats. These regions which are very generally correlated with areas of slight limestone in- fluence (see Map 2) are: a. The western upper peninsula (regions 7 and 8B) where surface waters are largely influenced by outcrops of sandstone and crystaline rocks, as well as acid, (generally none or only slight amounts of limestone) stony and sandy drift. The irregular, rugged terrain and poor drainage of this region are also influential in providing many softawater habitat. ‘ b. The dominant sandy regions (section 5 and 46 and 5A), especially in the upper central re- gion of the lower peninsula where a minimum influence of limestone and poor drainage makes possible a rich development of acid bogs. c. Parts of Chippewa, Luce, Alger and School- craft Counties (section 6) where great areas of swamps, marshes and peat deposits associated with the Manistique and Tahquamenon River drain- .age systems, as well as the slight limestone influence of the dominantly sandy drift permits a fair development of suitable desmid habitats. d. The irregular morainic area, extending from Oakland County, south and west through Washtenaw, Jackson, Calhoun and Barry Counties, in which the topography, poor drainage and other local conditions permit development of a few acid bogs, or other suitable habitats in a generally harddwater lake region. 'Many of these bogs are only slightly acid and have a poor desmid flora, but others have a conspicuous and rich desmid population. ' ' I ' v . . .I . . \ x) V' _ - ’ . .0 ' 4 ' x. J . ‘ I L .o ' x ,a. ‘ .1 I ‘I 0 ,— ' I’ v‘ .. '. 7‘ . ,2 | _ , \ . . I x: I o . N, \_ I . I ,’ I .I ‘ ‘ ‘ I N \ I v o i e - u . u .— a ,. he ‘ I n t * ‘ ,- ‘ ;’ l r .. r‘ ' 1 . - .0 .. - r- l I . n -. . 1. ' - - ‘ . ' I .1 .k\' r v . .Ln.. 1 ‘ J b ,. v .4 ' I L .... . -. ‘ H ’ '. J I -. ’ rt !‘ . >V. .« ‘t . ." ,3‘- - ...L r l -0- ,)~ o , . n | u .. . g ' r‘ \ . h .- l o . ‘J "l _ a I I \t 1 ,- L I no ,—s g x v . .< I“ . “a. v. ‘5‘-,__ :'-l’3;;€ , . .fin . I.“ ‘E; ., ’: 9.‘ ,- a. ‘ - 4? XI. SYSTEMATIC ACCOUNT A. Introduction In the following taxonomic portion of this paper, arti- ficial keys to both genera and species of Michigan desmids are presented. Each species, variety or form in the key possesses a number which corresponds to the same entry in the descriptive portion following each key. For each entry the following information is provided: 1. A standard reference. 2- Brief diagnostic comments. 3. Measurements. Those of the writer are always en- closed in brackets. Abbreviations used in this part are: L. - Length Lssp. - Length without spines Lcsp. - Length with spines Lsp. - Length without processes ch. - Length with processes w. - Width Wssp. - Width without spines Wcsp. - Width with spines Wsp. — Width without processes ch. —-Width.with processes ‘\ II I v D . ; . .5 ‘JJ -.A . a . A u 4 .. . 1 . . . . . . . i. . . 5. . L I . . O \ A .ll . . . . a . . . A . . . v. . L A II . Iv l «L . . A I w . v e .2 o . i . . . . _ .. I. . _ I .I . o . \I . aI. ., . x I. . a I ' r I . . J . n O . a m . b . A p .. . s L . v .a n , . . n. . . a . o x: , .\ (A . J ‘ t I . u o . o . _ . . . l I .1 I. . . _ n A a . I . . . L . v I s '\ 1 . . 9‘ . ,, a I . p y ‘K 48 I. - Isthmus A. - Apex B. - Base Sp. - Spines Distribution records for Michigan. The following symbols are used in this section: SLP - Southern Lower Peninsula (south of Bay City to Ludington line). NLP - Northern Lower Peninsula EUP - Eastern Upper Peninsula (east of Mar-- quette and Menominee Counties). WUP - Western Upper Peninsula. IR - Isle Royale. V A number in brackets after a county name indicates the number of stations in that county from.which the writer identified the organism. In addition, the following abbreviations for authors are used: (N and A 1932) - Nichols and Ackley. (Pres. and Mag. 1935) - Prescott and Magnotta. Plate and figure references following a species or variety name indicate that such entry is either a new record for the state of Michigan or new to science. Illustrations of species will be found on plates fol- lowing the taxonomic section of this paper. o - ‘ A . . , ‘ - . ' ~ . 0' i'. . -. . ‘ , . O p ‘1 O ~K ‘ F I r .y t . ' \ l n J . - D A , ‘ ‘ . o. . Y . . _ - 7‘ l ' . I! ‘ - . ) ‘ I. O / H l . - ~ . . ' ‘ - . l .. “ >‘ . ‘ 2 0.3- . J. . I . , . ' t . ‘ I I . .. - ‘ ' ."- . ' L ., ‘T ‘ . . I‘ . . .. ‘ d a . ‘ n ‘ ‘ . - - .‘ .. _. _ ~ I . . .| . n‘ v . . . II ‘ . .. . 1 . . ' v (' .~ ‘ '- ‘ .I . . ’ “L " .I_ . ‘ lo ‘ ~ “ u 1 1‘» '. .. I 1 . l . .fi ‘ ‘ I .— ii ‘ ‘ ’ I I . .. . . ’ . . - . . ‘ . i ‘ A . . . . ‘ . - ‘. H . v ’ k . . O V ~ A . ‘ .1 . . , I . ’ r . . ‘ . ‘ I ’ J .Io. I . . ~ ‘ k . I l . ,‘ . . I A K n d! . . V I.. . . . ‘ K ‘ . \ s. I L > .. . m ‘ I ‘ . A o I . a ‘ ’. . ‘ t I. 'v . . .V . . . ‘ . ‘ ‘ ‘ - . \ . - ' b. - . (I . - u . a o ‘ x K ‘ .r . ‘ ‘ - .‘ ~. . a I I ‘ I l ‘ , . . . I v I, A .. A . ._.‘ i- _ l . | . v - ‘ l ‘ ~ I . ‘ I " ‘« ..._ L »‘ .J . I _ ’ . . . . ' . I ' " ‘ ‘ ‘ ‘ I‘ an. 1 ' , “ . ‘ ‘ . a 49 B. Key to the Genera of Michigan Desmids 1. Cells solitary . . . . . . . . . . . 2 1. Cells either in filaments or in col- onies . . . . . . . . . . . . . . 24 2. Cell with a median constriction dividing the cell into symme- trical halves . . . . . . . . 3 2. Cell without a median constric- tion dividing the cell into symmetrical halves l4 3. length of cell over three times the width 0 C O O O O C O O C O O O O 1+ 3. length of cell not over three times the Width 0 O O O O O O O I O O O 7 4. Apical portion of the semicell with a vertical incision . . 5 4. Apical portion of the semicell without a vertical incision . 6 .5- Semicell wall ornamented with trans- verse rows of spines or verrucae . (12) Tripmoceras 5. Semicell wall not ornamented with transverse rows of spines or ver- rucae . . . . . . . . . . . . . . (13) Tetmemorus 5. Semicell base ornamented with a row of vertical plications . (ll) Docidium 6. Semicell base not ornamented with a row of vertical pli- cations . . . . . . . . . . (10) Pleurotaenium '7- Cells compressed, biradiate in ver- tical view . . . . . . . . . . . . 8 7- Cells not compressed; three to twelve radiate in vertical view arely certain forms of Arthro- desmns or Xanthidium). . . . . . . (21) Staurastrum 50 8. .Apical portion of the semicell with a vertical incision . . 9 8. Apical portion of the semicell without a vertical incision . ' lO 9. lateral margins deeply incised nearly to the midregion . . . . . (20) Micrasterias 9- lateral margins not deeply incised . (14) Euastrum 10. Lateral margins deeply incised, nearly to the midregion . . . (20) Micrasterias 10. Lateral margins notdifiégsed . . ll ll. Apical angles of semicells continued into two diverging processes . . . (21) Staurastrum 11. Apical angles of semicells not con- tinued into two diverging processes 12 12. Semicell wall with spines . . . 13 12. Semicell wall without spines. . (15) Cosmarium 13. Semicell wall thickened in median Portion . . . . . . . . . . . . . (19) Xanthidium 13. Semicell wall not thickened in med- ian pOrtiOn o e e o o o o o o o o 36 14. Cells elongate, straight or lunate . . . . . . . . . . . 18 . 14- Cells more or less ovoid . . . 15 15- The stellate chloroplasts present in each cell . . . . . . . . . . . . (3) Cylindrocystis 15. Tho stellate chloroplasts not present in each cell . . . . . . . . . . . 16 16. Chloroplasts axial . . . . . . 17 16. Chloro lasts arietal spirally twisged . .p. . . .’. . . . . (6) Spirotaenia 17- A single plate-like chloroplast ex- tending the entire length of the cell . . . . . . . . . . . . . . . (2) Mesotaenium. g e - . . C C “ . o a l . c n o ‘ I . g n I \ t e i \ . ' . u ‘ i . ‘ 1 ~ . . \ I O O O k . . . O I ’ — —. o - O O O s I \ . - I i o e o . e ' O O I o a r l . . a . r‘ C U C Q C . . . ’ O c O O b ' e e 0 Q " I ~ c , - . ' O Q I i .. . ' ’ . o n . . ‘l N. p - 1') m 1) VI. n. '5‘ 17. 19. 19. 21. 21. 23. 23. 25. 95. 51 Two chlorOplasts present in each cell, each chloroplast with long- itudinal ribs . . . . . . . . (9) Penium 18. Poles of cells acute . . . . . 19 18. Poles of cells broadly rounded or truncate . . . . . . . . . 20 Two chloroplasts present in each cell and not touching each other in center of cell . . . . . . . . (7) Closterium A single chloroplast present in each cell and interrupted in center of cell 0 O O O O O O O O O O O O O O (5) R0:2a 20. Poles of cells truncate . . . . (l) Gonatozygon 20. Poles of cells broadly rounded. 21 Chloroplasts axial . . . . . . . . . 22 Chloroplasts parietal spiral bands . (6) Spirotaenia 22. A single chloroplast present in each cell and not interrupted in center of the cell . . . . (5) Roya 22. Two chloroplasts present in each cell and not touching each other in center of cell. 23 Cells straight . . . . . . . . . . . (4) Netrium Cells curved . . . . . . . . . . . . 35 24. Cells united in filaments . . . 25 24. Cells arranged in a more or less globose gelatinous col- ony and connected to each other by gelatinous strands . (l6) Cosmocladium Length of cell over three to four times the width . . . . . . . . . (I) Pleurotaenium Length of cell not over three to 6 four times the width . . . . . . 2 26. .Apical portion of semicell in- cised . . . . . . . . . . .(20) Micrasterias 26. Apical portion of semicell not incised . . . . . . . . . . . 27 ~I I- I e I 0 'Q . .j. . . lx') ( I J Fl C... 27. 27. 29. 29. 31. 31. 33. 33. 35. 35. 52 Cells united by apical processes . 28 Cells not united by apical pro- . ceases C O O O O O O O O C O O O O 29 28. Processes short and interlocking often tuberculate . . . . . . (23) §phaerozosma 28. Processes long and overlapping adjacent cells . . . . . . . (22) Onychonema Vertical view elliptical or circular 30 Vertical view triangular or quad- rangular . . . . . . . . . . . . . 33 30. Vertical view elliptical . . . 31 30."Vertical view circular . . . . 32 Cells strongly compressed, narrow in thickness as seen in side or end View 0 O O O O O O O O O . O O O 0 Cells not thus strongly compressed 32. Semicell wall ornamented with longitudinal striae near the poles . . . . . . . . . . . . (24) Spondylosium . (27) Desmidium . (28) Gymnozyga 32. Semicell wall not ornamented with longitudinal striae . . ... ADices of young semicells infolded APices of young semicells not in- fOIded . O O C O O O C O C C C C 34- Vertical view triangular . . 34. Vertical view quadrangular . Apices with stout spine . . . . . Apices without a spine . . . . . . . (25) Hyalotheca . (27) Desmidium . 34 . (24) Spondylosium . (26) ghymatodocis . (8) Spinoclosterium . (7) Closterium 36. Semicell with spines present at each angle; semdcell wall without tubercles and a supra- isthmial granule . . . . . 36- Semicell with a single large . (17) Arthrodesmus spine at each basal angle oc- casionally one at each apical angle; semicell wall with tu- 53 C. Systematic List Division Chlorophyta Class Chlorophyceae Order Zygnematales 1. Family Gonatozygonaceae l. QQNATOZYGQE De Bary 1856 Cells cylindrical or narrowly subfusiform, many (up to 40) times longer than wide, without a median constriction; leteral margins parallel, sometimes slightly tapering to the truncate or subcapitate, sometimes dilated apices. Cell wall smooth or covered with granules or spines. Chloroplasts axial, usually irregular bands, one or two in each cell; nums brous pyrenoids regularly Spaced in a linear series. Cells Sometimes remaining attached in filaments of variable length after cell division, but separating when disturbed or prior t0 conjugation. zVsospore Spherical with walls smooth. Key to Species of Gonatozygon 1- Cell wall ornamented with granules or Spines . . . . . . . . O C O O 2 1. Cell wall smooth . . . . . . . . . . (1) c. Kinahani 2. Cell wall with short spines (less than 4.5u) or with .granules . . . . . . . . . . 3 2. Cell wall with long spines (5- 1011) Q C O O O C O O O O O C (2) G O aculeatum 54 ;3. Cell wall with granules (sometimes sharp or papilliform) . . . . . . 4 ‘3. Cell wall with short spines . . . . (6) G._pilosum 4. Cells long, narrow cylindrical- fusiform (usually 10—16, of- ten 30-40 times longer than wide), lateral margins taper- ing towards sub-capitate apices; granules variable, often sharp . . . . . . . . (3) G. Brebissonii 4. Cells cylindrical (10-25 times longer than wide) with apices very slightly dilated; gran- ules variable, often sharp or papilliform . . . . . . . . . (5) G. monotaenium 1- Gonatozygon Kinahanii (Archer) Rabenh West and West, 1904. Monogr. Brit. Desm., 1:35. Pl. 2, Figs. 1-3. This species is easily differentiated from other species of Gonatozygon by the smooth cell wall. Measurements: L. l45-(234)-375u; w. 10.5-(lO.6)-l7u. Distribution: NLP, Cheboygan (Taft 1939); EUP, Mackinac: WUP, Gogebic. 2. Gonatozygon aculeatum. Hastings Smith, 1924. Bull. Wis. Geo. & Nat. Hist. Surv. 57(2):5. P1. 52, Fig. 3. The presence of long, sharp spines (L. 4.5-9.5u) which are broader at their bases, easily distinguishes this from other>nichigan species. Measurements: L. (116)-125-300u; W. (10.6)-l2-20u. Distribution: NLP, Cheboygan (N &4 1932, fa. giggg, West and West); EUP, Chippewa. "err Huh.-. :u u .“u “a.“ any Ia ‘. H.‘ “'0 F o . . I a I . . u . e u ‘11 . I . . I 1| 55 3- Gonatozygon Brebissonii De Bary West and West, 1904. Monogr. Brit. Desm., 1:31. P1. 1, Figs. 8-11. This species is characterized by the long, narrow, nearly cylindrical subfusiform cells which are 10-16, sometimes 30-40 times longer than wide. The lateral mar- gins taper distinctly towards the subcapitate apices. The granules on the cell wall may be strongly developed and sharp. Measurements: L. 94-(140)-288u; W. 3.5-(5.2)-10.8u. Distribution: SLP, Barry; NLP, Cheboygan (Taft 1939); WUP, Houghton. 1h. var. minutum. West and West West and West, 1904. Monogr. Brit. Desm., 1:33. Pl. 1, Figs. 15, 16. This variety is much smaller than the typical. Measurements: L. 47.5-67.5u; W. 4.2-7u. Distribution: NLP, Cheboygan (Taft 1939). 5. Gonatozygon monotaenium De Bary West and West, 1904. Monogr. Brit. Desm., 1:30. P1. 1, Figs. 1-7; P1. 5, Fig. 5- This cylindrical species has the cell wall ornamented with small granules which may be sharp or even papilli- form. The cell is 10-25 times longer than wide, the apices slightly dilated with rounded angles. Specimens from.Roscommon had well-developed granules that were sharply pointed. F“ fiV 6. 56 Measurements: L. 82-(218)-284u; W. 7.5-(8.7)-ll.5u; A. 806‘12 .51). Distribution: SLP, Macomb (West and West 1898); NLP,. Roscommon. Gonatozygon pilosum Wolle Smith, 1924, Bull. Wisc. Geo. & Nat. Hist. Surv. 57(2):5. P1. 52, Fig. 2 This species has cells 12-20 times longer than wide. The lateral margins are somewhat variable, sometimes straight and parallel, at other times slightly attenuated outwardly to the dilated, truncate apices that have rounded angles. The cell wall is densely covered with short, straight and fine spines. The writer does not believe that Gonatggygon monotaenium var. pilosellum Nordst. can be accurately separated from this species, and thus all forms with short thin spines (under 4.5u long) are placed here. Measurements: L. 100-(211)-300u; W. 6-(9.6)-15u. Distribution: SLP, Calhoun, also Calhoun (Pres. & Mag. 1935, Q} monotaenium.var. pilosellum); NLP, Cheboygan, Emmet (Taft 1939); WUP, Gogebic. 2. Family Mesotaeniaceae 2. MESOTAENIUM Naeg.l849 Cells often cylindrical, longer than wide, usually straight, with truncate or rounded apices, free floating or pl film‘s-20‘ .“‘V‘-Odu I. ' n-n . ' «fill! '“‘VO VU.I a '35)? .' ‘ ‘Uh Man. He.- 1“ 'Oluv. 57 aggregated in gelatinous masses or mosses or wet rocks. Chloroplasts,one or two in each cell, axial, flattened plates with marginal notches; pyrenoids one or two in each chloro- plast. Nucleus is sometimes excentrically located and the cell sap may be colorless or purplish. Key to Species of Mesotaenium Cells over 3 times longer than wide. (1) M. Endlicheria- num Cells under 3 times longer than Wide 0 e e e o e e e e e e e o e o 2 2. Apices of cells truncately rounded . . . . . . . . . . . (2) M. macrococcum 2. Apices of cells rounded . . . . (3) M. De. Greyi var.’breve Mesotaenium Endlicherianum Naeg. Pl. 1, Fig. l. Krieger, 1933. Rabh. Krypt. Flor. l3(1):193. Pl. 3, Fig. 5. This species is over three times longer than wide, is mostly straight and has rounded apices. The cell sap may be colorless or purplish. The chloroplast may be single or there may be one in each semicell. A single specimen from Berrien County agreed well with the des- cription of this species. The chloroplast structure was slightly disintegrated, although there was a distinct py- renoid in each semicell. The cell sap was purple. The width (below 15u) places it here. Measurements: L. (23)-24-50u; W- 7-(11.5)-l2u. Distribution: SLP, Berrien. New record for Michigan. it: \ A ‘ "s! 58 2. Mesotaenium macrococcum (Kuetz.) Roy and Biss. Krieger, 1933. Rabh. Krypt. Flor. l3(1):198. Pl. 4, Figs. 1—3. This species is about 2 - 2 1/2 times longer than wide. The cells are cylindrical and the apices are truncately rounded. The chloroplast is a central plate, often with a notched margin. Measurements: L. 22-38u; W. 11-20u. Distribution: SLP, Washtenaw (West and West 1898). 3- Mesotaenium 29 Grey; var. 11319 W. West Krieger, 1933. Rabh. Krypt. Flor. l3(1):192. Pl. 3. Fig. 2. This organism (rarely curved) is usually two to three times longer than wide. The apices are rounded. The Goebic County specimens were intermediate in pro- portions between the typical and the variety 25332, but are assigned here because of the small size. Measurements: 32-(42)-65u; W. (13.5)-16-22u. Distribution: NLP, Cheboygan (Taft 1939); WUP, Gogebic. 3. CYLINDROCYSTIS Menegh. 1838 Cells elliptical or cylindrical with broadly rounded aDices and without median constriction. The cell wall is smooth. Each semicell has a somewhat stellate chloroplast YWith a central spherical or rod-shaped pyrenoid. The nucleus is.central in position and between the two chloroplasts. Zygospores spherical to rectangular, the wall smooth or With sharp angular projections. I‘ ‘n“: p 0| 4»... v. ' (1‘11 n 0' iv.. V . Q A".! vised O Av-‘l. E I e‘ V'e...¢ a. fire 29! C , .- \ Ob .- y ‘9‘. . . . ‘ ' va.. n) 59 Key to Species of Cylindrocystis 1. Cells elliptical . . . . . . . . . . (1) Cyl. crassa 1. Cells cylindrical with broadly rounded apices . . . . . . . . . . (2) 911, Brebissonii 1- Cylindrocygtis crassa De Bary P1. 1, Fig. 2. Krieger, 1933. Rabh. Krypt. Flor. 13(1): Pl. 6, Figs. 16,17. This species is broadly elliptical (about 1 1/2 - 2 times longer than wide). Measurements: L. 22-(29.8)-72u; W. 14-(15)-48u. Distribution: EUP, Schoolcraft. New record for Michigan. 2. Cylindrocystis Brebissonii Menegh. Krieger, 1933. Rabh. Krypt. Flor. 13(1):207. P1. 6, Figs. 4-7. This species is cylindrical with broadly rounded apices, and is about 2 - 4 times longer than wide. A single chloroplast in each semicell has a central py- renoid. Measurements: L. 30-87u; W- 14-35u. Distribution: SLP, Barry; NLP, Cheboygan (Taft 1939); EUP, Chippewa, Schoolcraft; Isle Royale (Prescott 1941). 3- var. m West and west Krieger, 1933. Rabh. Krypt. Flor. 13(1):209. P1. 8, Figs. 8, 9. This variety is smaller than the typical. Measurements: L. 20-30-(rarely up to 41u); W. 8-13u. Distribution: NLP, Presque Isle (Taft 1939). K‘I 1‘13“" . “'e~ “a: ‘ a. .‘ ‘ .a Df‘ . “I" '~ ‘ I 9 ' A I: “E \ ’1 CI J . A. 6O 4. NETRIUM Naegeli 1849 (Emend. Luetkem. 1902) Cells straight, always longer than wide, cylindrical or fusifonn with non-constricted lateral margins gradually atten--— uated to apices, or parallel and then strongly tapered to broadly rounded or conically rounded apices. Cell wall non- segmented, smooth and without pores. Chloroplasts axial, one or two in a semicell; each with 6 - l2 radiating longi- tudinal plates that are often notched at the edges. Pyrenoids, when single in each chloroplast, rod-shaped, when more than cme, spherical or irregularly shaped. Terminal vacuole with gypsum crystals in several species. Zygospore spherical with smooth thickened walls. Key to Species of Netrium 1- Cells cylindrical or elongate- cy- lindric O O O O O C O O O O O O O 1- Cells spindle—shaped . . . . . . . . (l) N, digitus 2. Semicells with two chloro- plaSts O O O O O O O O O O O O (4) E. inter; Egtum 2. Semicells with a single chloro- plast . . . . . . . . . . . . (5) N, oblongum 1» Netrium digitus (Ehrenb.) Itzigs. and Rothe Krieger, 1935. Rabh. Krypt. Flor. l3(1):215- P1. 7, Fis- 1: P1. 8, Fig. 1. This large species is three to four times longer than wide. The cells are spindle-shaped with the con- vex lateral margins tapering to the rounded truncate an” ‘~-'v . ‘5'. oh. I .0 n i. ("7 f 61 apices. The cell wall is smooth and the axial chloro- plasts are lobed, the lobes turning alternately to the left and right throughout the length of the chloroplast. A single central pyrenoid is present in each cell. Measurements: L. 100-130-(194)-(205)-400u; W. 30-(43)- (60)-80u. Distribution: Very widely distributed according to the writer's collections. SLP, Shiawassee, Barry (2), Wash- tenaw, Livingston, Oakland, Berrien; NLP, Cheboygan, Crawford, Presque Isle, also Cheboygan (N & A 1932); Welch (1936b, 1938a), Emmet (N a A 1932); EUP, Delta, Chippewa, Alger, Schoolcraft (3), also Mackinac and Chippew (N & A 1932); WUP, Gogebic (2), Marquette (2), Houghton; Isle Royale (Prescott 1937). 2. var. lamellosum (Bréb.) Gronbl. Kriegar, 1933. Rabh. Krypt. Flor. 13 (1):219. P1. 7, ; Fig. 6. This,variety has the lateral margins slightly re- tuse in the mid-region of cell. Measurements: L. 90-(200)-(334)-400u; W. 22-(45)-(59)-75u. Distribution: SLP, Washtenaw, Livingston, Barry; NLP, Cheboygan (Taft 1939); EUP, Schoolcraft, Delta; WUP, Mar- Quette; Isle Royale (Pres. 1941). 3- var. Naegelii (Bréb.) Krieger Krieger, 1933. Rabh. Krypt. Flor. l3(1):218. P1. 8, Figs. 4, 5. ’7‘ ’__a I” r 62 This variety is usually smaller than the typical. The cell is four to five times longer than wide, and the apices are broadly rounded. The cell sap sometimes has a red-violet color. Measurements: L. 90-(124)-390u; w. 21-(23.3)-60u. Distribution: SLP, Livingston; NLP, Cheboygan (N & A 1932, N, Naegelii); Isle Royale (Prescott 1941). Netrium interruptum (Bréb.) Luetkem. Krieger, 1933. Rabh. Krypt. Flor. 13(1):222. P1. 8, Fig. 8. This species has two chloroplasts in each semicell. The apices are conical, rounded, and almost truncate. The Michigan specimens are not as long as measurements given by Krieger (1933). Measurements: L. (123)-(128)-400u; w. (30)-30-(39)-80u. Distribution: SLP, Berrien; NLP, Cheboygan (Welch 1936b); WUP, Gogebic. 5. Netrium oblongum (De Bary) Leutkem. Krieger, 1933. Rabh. Krypt. Flor. l3(1):220. P1. 8, Fig. 6. This Species has a characteristic oblong cylindrical form, is three to four times longer than wide, and has broadly rounded apices. Measurements: L. 90-160u; w. 27-39u. Distribution: SLP, Kalamazoo: NLP, Cheboygan. Both re- cords (N a A 1932). -3 F V o .7; , e'; 1AA. A— .n, Java .1. \ JQN (v I! ' l \o P I J. , u- U. £525.. "‘-"*_I V 'e .: ..I‘: V . u ~ A- an‘ '\ s ‘- A I“: : n3~ ~.‘_‘ 'Q‘lh A " "'b l I :- ‘ . “‘v‘ \ ‘l 63 6. var. cylindricum West and West Krieger, 1933. Rabh. Krypt. Flor. l3(1):221. Pl. 8, Fig. 7. This cylindrical variety is usually smaller than the typical. The apices are broadly rounded. Measurements: L. (49)-53-(53)-150u; W. (15)-l7-34u. Distribution: NLP, Roscommon, Emmet, also Cheboygan (N a A 1932). 5. BQX§_West and West 1896, emend. Hodgetts 1920 Cells cylindrical or subcylindrical, unconstricted, straight or slightly curved. Lateral margins very slightly tapered to the rounded or truncate apices. Cell wall smooth and colorless. The axial chloroplast, single in each cell, the edges sometimes recurved, and sometimes exhibiting sharp ridges, extending often the entire length of the cell, rarely one in each half of the cell. Pyrenoids 2-14, arranged in linear series. A terminal vacuole present in one variety. Zygospores spherical to oval, with smooth walls. Key to Species of Roya 1- Cells fl-lO times longer than wide . 1- Cells over 10 times longer than "16.6 o o o o o o o o o o o o o o 2. Width of cell 7.5-9u . . . . . (2) 5, obtusa var. aggIIca . (l) g, cambrica fa. 2. Width of cell 4.5-7u . . . . . (3) g, obtusa var. mon ana _"-¢ 64 1d Roya cambrica West and West fa. Pl. 1, Fig. 3. Krieger, 1933. Rabh. Krypt. Flor. l3(1):206. P1. 5, Fig. 9. This species is typically 25-27 times longer than wide, slightly curved and very slightly attenuated near the apices. A few specimens from Gogebic County are about one-half the size of the typical, the measurements being only 20 times longer than wide. The apices are also more truncate than the typical. Measurements: L. (91.5)-173-195u; W. (#.3)-6.2-7.5u. Distribution: WUP, Gogebic. New record for Michigan. 2- 39E obtusa var. anglica (G. S. West) Krieger Krieger, 1933. Rabh. Krypt. Flor. l3(1):205. Pl. 5, Figs. 7, 8. This organism can be separated from other species of 5213 by the width (7.5-9u) of the cell and the pro- portions of the cell (4-10 times longer than wide). This is the only form with terminal vacuoles. I Measurements: L. 35-80-112u; W. 7.5-9u. Distribution: SLP, Ingham (N a A 1932) - 3* Bgz§.obtusa var. montana West and West Pl. 1, F18- 4- Krieger, 1933. Rabh. Krypt. Flor. l3(1):205. P1. 5, F188. 5, 6. This variety can be separated from the variety ag- 511°; by the narrow width (4.5-711) - Measurements: L. 16-(36)-93u3 W- 4.5—(5.3)-7u. Distribution: WUP, Gogebic. New record for Michigan. .— l _- ...-~- , ......—— 1' 1m, ...—...... - O , . v . 1 . , . r - . . . I v I . \ v - Q I . . I 0 t ' I . n I . ‘ . s C O 0 o . . ‘ l o . o . o . . . .. O . . . n «a veofi 0 Par -'.-- ~"‘O:~oo- U :l.'.;‘ "'I‘V. ‘. . ;:IR: q “ole, N V flA‘. 3:- ~73. 'gve‘) ’- «vfi t. “I V 1 h n V 65 6. SPIROTAENIA Breb. 1844 Cells, unconstricted, fusiform elliptical or cylindrical, straight or slightly curved, with acute or rounded apices. Cell wall colorless, smooth and without pores. Chloroplasts, either axial with sharp spiral ridges, or parietal liminate bands, spirally twisted to the left (one-half to sixteen turns per cell), the ends sometimes colored red. The nucleus is ex- centric, internal to chloroplast in cells with a parietal chloroplast, external to the chloroplast in cells with an axial chloroplast. Zygospores single or in pairs, generally spherical with smooth, short Spiny or areolate walls. Key to Species of Spirotaenia 1. Cells small, less than 30u long . . (l) §23 minute 1. Cells large, over 60u long . . . . . (2) g2. condensata 1” §pirotaenia minuta Thuret Krieger, 1933. Rabh. Krypt. Flor. 13(1):l86. P1. 2, Fig. 8. This small fusiform species is 6-10 times longer than.wide. Measurements: L. 15-27u; w. 3-4u. Distribution: NLP, Cheboygan (N 8c A 1932). 2' §Pirotaenia condensata Breb. Krieger, 1933. Rabh. Krypt. Flor. 13(1):l81. P1. 2 Fig. l. I 66 This long cylindrical species with rounded apices shows from7-l6 turns of the spiral parietal chloroplast. Measurements: L. 60-(113)-33#u; W. lO-(ll.5)-30.#u. Distribution: SLP, Livingston; NLP, Cheboygan (N & A 1932); EUP, Schoolcraft; WUP, Gogebic; Isle Royale (Pres- cott 1937, 19u1). 3. Family Desmidiaceae 7. CLOSTERIUM Nitzsch 1817 Cells always longer than wide, generally greatly elong- ated; lateral margins attenuated to the apices, mostly curved, rarely straight; without a median constriction; apices acute, obtuse, truncate or rostrate. Cell wall smooth, striated, costate, striate-punctate, or punctate; colorless to brownish, sometimes transversely subdivided into girdle bands. Chloro- Plasts, single in each semicell, margins entire or'with.longi- tudinal ridges radiating from a slender central axis, usually with an axial row of pyrenoids. Cell contents with a terminal vacuole at each pole containing one or more vibrating gypsum crystals 0 Zygospores quadrangular, ovoid, spherical or ellipsoid; With a thick, smooth, or scrobiculate wall. 1 A,q-_ ‘ - .. Vino»; n0 V. . . - . 1" $5.: I . 1‘.qu ,u D a .. “v.‘: D U 1 ‘ A ' ' c. . . . o h C. o _- ._ .-- ‘ _ . ' ,4“. u I. 1“ - - I i N A; . | 1 . ‘ . ve‘ ‘ ‘i - , , ‘ . “ H ' \ ‘ ' I o . Q .i ‘ . ‘ . ‘ ‘ ‘ I O s ‘ ... . . ‘ \ ‘ ' . , ‘ - ‘ r , I. L C I - : x l V . ‘ - . ' r . , D ' a ‘ ‘ . _ .. I , _ ‘ ‘ \ n 4 l ‘ o' 1 . I _ n I _ l k - ‘ I u . _ ‘ -‘ ‘i L 1 .. I . - ' i . i ‘ ' . \ '7‘ x x . , _ . . - l i ' a . A Key to Species of Closterium (Modified in part after Krieger, 1935) 1” Cells with girdle bands (sections of new wall interpolated, form- ing transverse bands) . . . . . . 1. Cells without girdle bands . . . . . 2. Cell wall smooth (very old empty semicells may show sculpturing under very high magnification . . . . . . . . 2. Cell wall not smooth . . . . . 3- Cells sharply curved, lunate . . . . 3- Cells slightly curved . . . . . . . 4. Cell 9-14 times longer than wide . . . . . . . . . . . (36) Cl, abruptum 4. Cell 25-35 times longer than wide . . . . . . . . . . . 5. lateral margins parallel for about 1/3 the distance from the middle of the cell to the apex; apices bluntly rounded; cell lunate-ba— cilli-form . . . . . . . . . . . (74) Cl. c this 75:- TEE—lam 5. lateral margins tapering gradually from middle of cell to the apex; apices less bluntly rounded than above; cell lunate . . . . . . . . (73) Cl, cygthia var. Jenneri 6. Cell wall striated(with longi- tudinal low ridges, but not short irregular longitudinal stria-like strips or puncta- 67 16 *’ Kn ow to (40) 91, macilentum 1310118 0 o o o o o o o o o o o 7 6. Cell wall costate (with well- defined lon itudinal rib-like thickenings or otherwise marked or smooth . . . . . . 13 .fif“lb‘ A D June I“ U a - u'- " UVM- v-b - I‘ A. ‘- a.-. u g“. H , v4- ’v 6.. . I" , u ”d“ t A- ‘Jh ‘v. ‘p. 68 7. length of cells usually over 180u; cell 10-11 times longer than broad, the apices rounded and gradually tapered . . . . . . . (75) _1, Archerianum 7. length of cells less than 180u; cell 6-10 times longer than broad, the apices broadly rounded and only slightly tapered . . . . (72) 8. Lateral margins tapering very slightly toward broadly rounded apices . . . . . . . . (58) 8. Lateral margins tapering dis- tinctly toward apices . . . . 9 9- Apices broadly truncate (sometimes Oblique 1y) 0 O O O O O O O O O O 0 lo 9- Apices otherwise . . . . . . . . . . . . (57) l. striolatum 10. Cell width over 26u . . . . 10. Cell width under 26u . . .'. . ll 11. Cell width 6-11m . . . . . . . . . . (54) Cl. Iguneidum var. Elonga um 11. Cell width 15-25u . . . . . . . . . (55) g. intermedium 12. Poles angularly rounded . . . . (51) g_, turgidum l2. Poles truncate . . . . . . . . (41) _1, acerosum 13. Cell wall with costae (ribs) . . . . 14 13. Cell wall with other type of marking or smooth . . . . . . . . . . . . 15 14. Cells 4—10 times longer than Wide 0 o o o o o o o o o o o (68) 9}“ COStatum 14. Cells more than 12 times longer than broad . . . . . . (71) 91, angustatum 15. Cells 13-26 times longer than broad. (53) 91, subscoticum 15- Cells up to 10 times longer than broad . . . . . . . . . . . . . . (47) 91, didymocotum ’._...._ O u o 0 e O O ‘ n ‘ O n e O o n C I a q ' 3 '6' U A ‘I ‘ 'I- ‘l 17. 17. 19. 19. 21. 21. 93. 23. 16. Cells strongly curved . . . . 16. Cells slightly curved or not curved . . . . . . . . . Cell wall smooth . . . . . . . . . . Cell wall striated . . . . . . . . . l8. Apices narrowly and obliquely truncate . . . . . . . . . . l8. Apices not obliquely truncate. Width of cells 5- llu, middle of cell never tumid . . . . . . . . . Width of cell more than lOu, mid- region of cells often tumid . . . 20. Apices rounded . . . . . . . . 20. Apices somewhat pointed . . Pyrenoids scattered . . . . . . . . Pyrenoids arranged in a longitudinal linear series . . . . . . . . . 22. Cell 4-5 times longer than wide, apices usually very broadly rounded, midregion of cell slightly tumid . . 22. Cell more than 5 times longer than wide, apices rounded , middle of cell tumid Apices acutely rounded, cell strongly curved (dorsal margin 135° 4%0 of arc) . . . . . . . Apices obtusely rounded, cell less strgnglyocurved (dorsal margin 100 ~1lO of arc) . . . . . (24) var o (27) var . (28) (21) (22)C (26) 69 l7 25 18 Cl. Ehrenbergii malinvernianum 19 20 Cl. calosporum B_asillense ‘91. Dianae 21 24 Cl. Ehrenbergii 22 C1. eboracense 23 Cl. Leibleinii Cl. moniliferum __.___,_____——_- ~— . l _. =.- ..———. _ o . . I o D ' I . . - . , r u o a o o . . s . o u . . o e u - . c . n o . o o . , .. a. _ . I“ v - a - o o o . . . . ’i n u o H . . v - ‘ a o o . « . C o . . , . . o . u a a o n o o v . . . . “ I ‘ ‘ . | I . . . ’ k ‘ l ‘ t n ‘ . Q . . . , i ‘ a Q ' D U n o . .. - o . I . . ‘ . , (I 4 A .I Q vy" ‘u q I“ ~...' Hr? 25.. 25. 27. 27. 29. 29. 24. Each chloroplast with l or 2 pyrenoids; dorsal margin with curvature of 1500-180o of arc; cell length 30- 85u; cell width 6-l4u . . . . 24. Each chloroplast with 2-5 pyre- noids; dorsal margin with curvature of less than 150° of arc; cell len th 57-205u, cell width 8.5-2 u (5-llu in var. angustum.which is 12-15 times—longer than wide); api- cal thickening often present. Cell straight, the dorsal and ven- tral sides not differentiated . . Entire cell not straight, at least the apices curved; dorsal and ven- tral sides differentiated . . . . 26. Cell 3-5 times longer than wide usually small (L. 24- 93u3 W. 7. 5- 22u) . . . . . . . 26. Cell 5-8 times longer than wide usually larger (L. 75-450u3 W. 15-55u) . . . . . . . . . Lateral margins tapering sharply from a broad midregion into seta- like extremities . . . . . . . . . Lateral margins usually tapering from sometimes tumid midregion, but not into sets-like extrem- ities . . . . . . . . . . . . . . 28. Midregion of cell body tapering abruptly into long Beta-like extremities . . . . . . . . . 28. Midregion of cell body tapering gradually into long seta-like extremities . . . . . . . . . Cell 11-16 times longer than wide Cell 20-30 times longer than wide 70 (15) Cl, venus (18) 92;. parvulum 26 27 (4) Cl, Navicula (1) Cl, Libellula 28 3O (67) 91, setaceum 29 (66) Cl. rostratum (65) 91, Kuetzingii . . O . e s a o . . . I b » . I 0 . u I . . ' I . ‘ _n a I n a u . ‘A “V. "P .JI ( A) l'\) 31. 31. 33. 33. 35. 35. 37. 37. 71 30. Lateral margins tapering grad- ually to acuminate or acutely rounded apices (rarely truncately and nar- rowly rounded) . . . . . . . 31 30. Lateral margins tapering grad- ually to truncate apices or to truncate apices with rounded angles . . . . . . . 35 Width of cell over 12u (rarely lOu). (31) 91, strigosum Width of cell up to 12u(rarely 12.5) 32 32. Length of cell less than 200u (rarely up to 215u) . . . . . 33 32- Length of cell more than 200u . 34 Midregion of the cell tumid . . . . (9) 913 subulatum Midregion of the cell not tumid . . (6) Cl, acutum 34- Cell more than 60 times longer than wide . . . . . . . . . . (11) _l. aciculare 34. Cell less than 60 times longer than wide . . . . . . . . . . (10) l. pronum Apices truncate . . . . . . . . . . 36 Apices rounded, angularly rounded or truncately rounded . . . . . . . . 46 36. Apices abruptly narrowed, some- ' what conical (usually large Species) . . . . . . . . . . 37 36. ,Apices gradually narrowed . . . 38 Cell wall striated . . . . . . . . . (60) _l, attenuatum Cell wall with paired longitudinal L rows of coarse punctations, cell Wall finely punctate between rows. (59) .1: Braunii 38- Cell wall smooth . . . . . - - 39 38- Cell wall striated, costate or 4 strongly punctate . . . . . . 3 .1 A ‘v. 72 Midregion of cell tumid . . . . . . 40 Midregion of cell not tumid . . . . 41 40. Cell 6-13 times longer than wide . . . . . . . . . . (12) Cl. tumidum 49. Cell 20-23 times longer than wide . . . . . . . . . . . . (14) C1. idiosporum Cell gradually narrowed, uniformly and slightly curved towards apices . . . . . . . . . . . . . . (13) 91, cornu Cell straight in midregion, the slightly narrowed apices inwardly curved . . . . . . . . . . . . . . 42 42. Width of cell 8-20 wu . . . . . (37) Cl, toxon 42. Width of cell up to 8u . . . . (38) Cl, gracile Cell wall striated . . . . . . . . . 44 Cell wall not striated . . . . . . . 45 44. Cell tumid in midregion . . . . (61) 9;, Ralfsii 44. Cell not tumid in midregion . . (63) Cl, lineatum Cell wall punctate, the apical area darker brown, and more strongly punctate . . . . . . . . . . . . . (49) 91, Baillyanum Cell wall costate (with ribs) . . . (64).Ql° lineatum var» costatum 46. Apices broadly angularly rounded . . . . . . . . . . . (51) l. turgidum. 46. Apices narrow and truncately rounded, or apices rounded . I 47 APices sharply narrowed, then trun- cately rounded . . . x . . . . . . 48 APices gradually narrowed, then rounded C O O C O C O . O C C C . 5 1 48. Apices recurved . . . . . . . . 49 48. .Apices not recurved (sometimes slightly) 50 . I“ 1.. 1‘; " I - ti“, -‘ia 1511’. :f\ JV! 'A {VI “4 49. 49. 51. 51. Width of cell more than 27u . . . . (45) __. 73 Width of cell less than 27u . . . . (46) C1. praelongum . Pritchardianum H 50. Cell almost straight, ventral margin straight or convex; 5-10 times longer than wide . (44) 91. lanceolatum 50. Cell somewhat curved, ventral margin mostly concave, rarely straight, 7-33 times longer than wide . . . . . . . . . . (41) Cl, acerosum Pyrenoids scattered . . . . . . . . (33) 91, Lunula Pyrenoids in a single linear longi- tudinal series . . . . . . . . . . (30) Q1, littorale Closterium Libellula Focke Krieger, 1935. Rabh. Krypt. Flor. l3(1):254. P1. 12, Figs. 1, 2. This species is 5-8 times longer than wide. The shape is fusiform with the lateral margins tapering gradually to the broadly rounded, truncate apices. The terminal vacuoles have 6-20 gypsum crystals and each chloroplast has 3-6 pyrenoids. Measurements: L. l70-(233)-450u; W. 30-(42)-52u. Distribution: SLP, Berrien; NLP, Cheboygan (N & A 1932); WUP, Gogebic (2); Isle Royale (Prescott 1937). 2. var. intermedium. Roy and Biss. Krieger, 1935. Rabh. Krypt. Flor. 13(1):255. P1. 12, Piss. 3. 4. 5. This variety is separated from the typical by its smaller size. The cells are usually about 5 times longer . e ‘ 0 n o D . ~ . e e o n k ' '5’ t . e . . . I o . L . 1' " Q - . me. Ill SE ~ Z- 781" ti. 74 than‘wide. Measurements: L. 75-170u; W. 15-36u. Distribution: EUP, Schoolcraft; WUP, Gogebic, also Mar- quette (Pres. & Mag. 1935, Penium libellula var. i233;- medium.Roy & Biss); Isle Royale (Prescott 1937). 23- var. interruptum (West and West) Donat Krieger, 1935. Rabh. Krypt. Flor. l3(1):256. P1. 12, Fig. 6. This variety has four axial chloroplasts arranged in a longitudinal series. This form may be only a typi- cal 92: Libellula in which the chloroplasts normally may be subdivided in older cells. Measurements: L. 90-400u; W. l6-55u. Distribution: NLP, Cheboygan (N & A 1932, Welch 1938a). 4. ClosteriumiNavicula (Breb.) Luetk. Krieger, 1935. Rabh. Krypt. Flor. l3(1):257. P1. 12, Figs. 8-10. ' This small species is about 3 1/2 - 5 times longer than wide. The cell is fusiform.with the apices broadly or truncately rounded. The cell wall is smooth and color- less. The terminal vacuoles usually have a single gypsum crFatal, and each chloroplast has a single pyrenoid. Measurements: L. 24-(32)-93u; W. (7.5)-8-22u. Distribution: SLP, Berrien; NLP, Cheboygan (N a A 1932, Welch 19383); EUP, Schoolcraft; WUP, Houghton, Gogebic; Isle Royale (Prescott 1941). t} 75 5. var. crassum (West and West) Gronbl. Krieger, 1935. Rabh. Krypt. Flor. l3(1):258. P1. 12, Figs. 11, 12. This variety is more robust than the typical, being about three times longer than wide. The apices are trun- cately rounded. Measurements: L. 22-52u; W. 8-l7u. Distribution: NLP, Emmet, Cheboygan (N & A 1932) 6. Closterium acutum.Bréb. Krieger, 1935. Rabh. Krypt. Flor. l3(1):259. P1. 13, Figs. 10-13 This species is 20-30 times longer than wide. The lateral margins taper very gradually to the acute apices. The curvature of the cell is slight. The cell wall is colorless and smooth, the chloroplasts have 2-4 pyrenoids, and the terminal vacuoles have either one or two gypsum crystals. Measurements: L. 90-155-(l6l)u; W. 4-(5.3)-6u. Distribution: NLP, Cheboygan (N & A 1932); EUP, Chippewa; WUP, Houghton, Baraga, Gogebic. 73 var. variable (Lemmermann) Krieger Pl. 1, Fig. 6. Krieger, 1935. Rabh. Krypt. Flor. l3(1):262. P1. 13, Figs. 18-22. This variety is somewhat more stout than the typical (14-19 times longer than wide). It is very variable in the degree of curvature exhibited, and sometimes only aha.“ " Var. 76 cell will have a curvature. sigmoid forms were found in Barry County. Measurements: L. 43-(60)-l40u; W. 2.5-(3.5)-5u. Distribution: SLP, Barry. New record for Michigan. 8. var. linea (Perty) West and West 10. Krieger, 1935. Rabh. Krypt. Flor. l3(1):261. P1. 13, Fig. 15. This variety is usually more slender and more elon- gate than the typical, and is not curved or is very slightly curved. Measurements: L. lOO-l68u; W. 3-3.5u. Distribution: NLP, Cheboygan (N & A 1932). Closterium sublatum (Kuetz.) Breb. Pl. 1, Fig. 7. Krieger, 1935. Rabh. Krypt. Flor. 13(1):262. P1. 13, Figs. 7, 8. This species is typically 15-21 times longer than wide. The cell is slightly tumid in the middle, and the lateral margins taper gradually to the acutely rounded, slightly incurved apices. The cell wall is colorless and smooth. Each chloroplast has 3-5 pyrenoids, and the terminal vacuoles have about four gypsum crystals. Measurements: L. lO2-(l63)-215u; W. 5-(7.5)-l2.5u. Distribution: SLP, Washtenaw. New record for Michigan. Closterium pronum.Br6b. P1. 1, Figs. 8, 9. Krieger, 1935. Rabh. Krypt. Flor. 13(1):263. P1. 13, Figs. 5, 6. ....th u . . I x \ - J . . . . , l a . n . C l I 1 I . .. . . . 'v - . ‘ . a I I . - o l . o a . ~ . \ , o o ‘ v a n I o _ O . . . - O I h - I ‘ , J 1 . ... ' — o ' e , - ' n . 01 O u. is: I". \v 77 This slightly curved species is typically 35-50 times longer than wide. The lateral margins taper grad- ually to the inwardly turned, very narrow but truncately rounded apices. The cell wall is colorless and smooth. The chloroplasts each have 5-10 pyrenoids, and the ter- minal vacuoles have l-6 gypsum crystals. Specimens from Chippewa County appeared somewhat intermediate between 91, pronum and Cl, subulatum (Kruetz.) Breb. The cells are about 35 times longer than broad. The midregion of the cells are slightly tumid, and the apices are slightly more incurved, and almost seta-like. Specimens from.Ber- rien County were found in reproductive stages. The zygospore is unknown according to Krieger (1935). The one specimen observed by the writer was transversely rectangular with the dorsal and ventral margins sharply convex, and with the angles forming short, rounded lobes projecting into each semicell. The wall was colorless and smooth. Measurements: L. ago-(230)-(290)-480u; W. 5-(6-3)45-5)- l2u; A. 2n. Zygospore: Transverse measurements: 36.6u; Longitudinal measurement: 19.4u. Distribution: SLP, Berrien; EUP, Chippewa. New record for Michigan. 11' 9198terium.aciculare T. West Krieger, 1935. Rabh. Krypt. Flor. 13(1):265.‘ P1. 13, Figs. 1, 2. ,l..__—-_ ...——__ NW1 . A. (I) I 78 This species is 65-144 times longer than broad. The lateral margins taper very gradually to the slightly in- curved, acute or acutely rounded apices. The cell wall is colorless and smooth, the chloroplasts have up to 20 pyrenoids in each semicell, and the terminal vacuoles have 1-3 gypsum crystals. Measurements: L. 390-800u; W. 4-8u; A. 1.5-2u. Distribution: NLP, Presque Isle (Taft 1939, 91, aciculare var. subpronum West and West). l2. Closterium tumidum Johnson Krieger, 1935. Rabh. Krypt. Flor. l3(1):267. P1. 14, Figs. 10, 11. This Species is 6-9 times longer than wide. The lateral margins (dorsal slightly curved, ventral broadly tumid or almost straight) taper gradually toward the roundly truncate apices that are variable in width. The cell membrane is smooth and colorless, the terminal vac- uoles each usually have one compound gypsum crystal, and the chloroplasts each have 1-4 pyrenoids. Measurements: L. 60-(134)-160u; W. 7-(17)-20u. Distribution: Washtenaw, Barry also Ionia (N a A 1932); NLP, Cheboygan, Newaygo (N & A 1932); WUP, Gogebic. 13- glosteriun: 9.9.529. Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. l3(1):269. P1. 15, Figs. 5-9. This small slightly curved species is 12-21 times longer than wide. The dorsal margin is convex and the ___,i "pv- 1.. l} 79 ventral margin is slightly concave or straight. The apices are truncately rounded. The cell wall is smooth and colorless, and the terminal vacuoles each have a single gypsum crystal. The chloroplasts contain four pyrenoids in a linear series in each semicell. Measurements: L. 95-(108)-(l6l)-180u; W. 5-(5.2)-(8.6)- llu; A. 2.5-3.5u. Distribution: SLP, Calhoun, Barry; NLP, Cheboygan (N & A 1932); WUP, Gogebic. l4. Closterium idiosporum West and West P1. 2, Fig. 3. Krieger, 1935. Rabh. Krypt. Flor. l3(1):271. P1. 15, Figs. 1, 2. This species is 20-23 times longer than wide. The lateral margins taper gradually from the slightly tumid midregion of the cell to the slightly incurved truncate apices. The cell wall is colorless and smooth. The terminal vacuoles contain numerous gypsum crystals. The chloroplasts each have 3-5 pyrenoids arranged in a lin- ear series. This species was collected in reproductive state from Chippewa County. Measurements: L. 22l-(258)-260u; W. lO-l4u; A. 2u. Zy- gospore: L. 55-58-(60)u; W. 29-(30)-30u. Distribution: EUP, Chippewa. New record for Michigan. 15- Closterium‘Venus Mfuetz. Krieger, 1935. Rabh. Krypt. Flor. l3(1):272. P1. 16, Figs. 1-5. m: p- Oanv "3). l O AA: .4. (1‘) (‘ 4 S” n, 80 This small species is 8-9 times longer than.wide. The curvature is strong and the midregion is not tumid. The apices are acute or sharply rounded. The cell wall is colorless, (rarely brown), and smooth. The terminal vacuoles have a single large gypsum crystal or several small ones, and the pyrenoids (~2) in each chloroplast are in a linear series. Measurements: L. 48-(65)-85u; W. 6-(9)-llu. Distribution: SLP, Calhoun, Barry (2), Washtenaw (2), Oakland, Jackson, Livingston, also Wayne (Campbell 1886) and Macomb (Pieters 1894); NLP, Cheboygan (N & A 1932); EUP, Schoolcraft; WUP, Marquette, Menominee, Gogebic; Isle Royale (Prescott 1941). 16. var» incurvum (Breb.) Krieger Krieger, 1935. Rabh. Krypt. Flor. l3(1):273. P1. 16, Figs. 16, 17. This variety is somewhat stouter (5-7 times longer than wide) and more strongly curved than the typical. Measurements: L. 30-(70)-80u; W. 6-(13)-l4u. Distribution: SLP, Oakland; NLP, Cheboygan (N & A 1932). 13} var. gerrucosum. (Roll) Krieger Pl. 3, Fig. 5- Krieger, 1935. Rabh. Krypt. Flor. l3(1):274. Fl. 16, Fig. 8. This variety is characterized by the presence of smallgranules, arranged irregularly upon the cell wall. Krieger (1935) states that the granules may represent 81 the outer part of the pore apparatus. Only a single specimen was seen by the writer and it may have been the typical 9;, XEEEE in some unknown physiological condition. Measurements: L. 57-61-(62)u; W. (8.5)-lO.8u. Distribution: SLP, Livingston. New record for Michigan. 18. Closterium parvulum Naeg. Krieger, 1935. Rabh. Krypt. Flor. l3(1):275. P1. 16, Figs. 1u-17. This Species is 7-10 times longer than wide (9-15 according to West and West 190#). The cell wall is smooth and colorless. The curvature is strong with the ventral margin concave and without any tumidness in the midregion. The apices are usually acutely pointed but sometimes acutely rounded, and often show an apical thickening (endpore). The terminal vacuoles each have 2-8 gypsum crystals and the 2-5 pyrenoids are in a lin- ear series. This species is similar to El, Dianae (lo-12 times longer than wide) but is usually much smaller (7-10 times longer than wide). Measurements: L. 60-(96)-(108)-160u; w. 9c(11.5)-(15)-17u. Distribution: SLP, Calhoun, Washtenaw, Barry, also Ionia (Wade 1949), also Branch, Wayne (N a A 1932); NLP, one- boygan (N & A 1932, Welch 1936a); EUP, Schoolcraft, Alger; WUP, Marquette, Gogebic; Isle Royals (Prescott 1941). "a ‘c I6; '1' Kr n—~1 V‘ 19. 20. 21. 82 var. angustum ‘West and West Krieger, 1935. Rabh. Krypt. Flor. l3(1):277. P1. 16, Figs. 20-21. This variety is separated from the typical by the greater length-width ratio (12-15 times longer than wide). The apices are sharply pointed and the curvature is variable. Measurements: L. 75-(97)-132u; W. 5-(7)-llu. Distribution: SLP, Barry; NLP, Emmet (N & A 1932). var. magus West Krieger, 1935. Rabh. Krypt. Flor. l3(1):277. P1. 16, Fig. 18. This variety is larger than typical. Measurements: L. l60-(l66)-205u; W. l7-(23)-28u. Distribution: EUp,jMackinac; Isle Royals (Prescott l9#l). Closterium eboracense (Ehrenb.) Krieger, 1935. Rabh. Krypt. Flor. l3(1):282. P1. 17, Fig. 4. This species is 4-5 times longer than wide. The cell walls are colorless and smooth, the vertical mar- gin is concave but is sometimes tumid in the midregion. The curvature varies from strongly curved to almost straight. The poles are usually very broadly rounded and the terminal vacuoles have about ten gypsum crystals. The 3-5 pyrenoids in each chloroplast are always in a row. Specimens from Washtenaw County had the poles less broadly rounded than typically. It. .flu (... 83 Measurements: L. l40-(23#)-294u; W. 35-(55)-69u. Distribution: SLP, Washtenaw, also Wayne (Campbell 1886); NLP, Cheboygan (N & A 1932). 22. Closterium Leibleinii Kruetz. Krieger, 1935. Rabh. Krypt. Flor. 13(1):284. P1. 17, Figs. 5-7. This species is 6-8 times longer than wide. The wall is smooth and colorless, rarely yellow-brown. The dorsal margin is variable but the ventral margin is con- cave and characteristically tumid in the midregion. The apices are acutely rounded, sometimes almost subacuminate. The terminal vacuoles have 8-12 gypsum crystals and the h-B pyrenoids in each chloroplast are in a linear series. This species resembles 913 moniliferum, from.which it can be separated by the greater curvature and the more strongly attenuated apices. Measurements: L. 90-(lBO)—(187)-260-(26l)u; W. 14-(30)- (3#)-(#3)-45u. Distribution: SLP, Calhoun, Barry, also Allegan, Barry, Branch, Lapeer, Saginaw, Sanilac (N & A 1932), Macomb (Pieters 1894), Van Buren (Transeau 1917), Wayne (Camp- bell 1886); NLP, Presque Isle, also Cheboygan (N & A 1932, Neal 1948); Isle Royale (Prescott 1941). 23' Elosterium.Ehrenbergii Menegh. Krieger, 1935. Rabh. Krypt- Flor. l3(1):285- Pl. 17, Fig. 1; 91. 18, Fig. 1. 5': (‘9 l. .7 8# This species is 4-6 times longer than broad, with a fairly sharp curvature. The ventral margin in the mid- region is distinctly tumid, and the dorsal margin is strongly convex. The margins taper gradually to the rounded apices. The cell wall is colorless and smooth, and the terminal vacuole has a large number of gypsum crystals. The pyrenoids are numerous and scattered. This latter feature easily distinguishes this organism from many other species of Closterium. Measurements: L. 230-(298)-880u; W. 44-(6l)-172u. Distribution: SLP, Allegan, Genesee, Hillsdale, Ingham, Ionia, Lenawee, also Macomb (Pieters 1894), Saginaw (N & A 1932), Allegan and Oakland (Transeau 1917); NLP, Cheboygan N a A 1932); EUP, Mackinac (N a A 1932, Transeau 1917); WUP, Marquette. 2#. var. Malinverfanum. (De Not.) Rab. Krieger, 1935. Rabh. Krypt. Flor. l3(1):287. P1. 18, Fig. 2. This variety is separated from the typical on the basis of a brownish cell wall which is finely striated (12-20 per lOu). Measurements: L. 220-(419)-620u; W. 32-(75)-l48u. Distribution: SLP, Washtenaw, also Macomb (Johnson 189h, 2;; Mglinvernianum); NLP, Cheboygan (N & A 1932, 913'Malf invernianum). 25. var. immane Wolle Krieger, 1935. Rabh. Krypt. Flor. l3(1):288. P1. 18, Fig.4. 4?) C! -/ A h] ... v . 7 U ‘ 85 This variety listed by Krieger (1935) as var. per- crassum (Borgc) Gronblad is more robust and wider than the typical. It is 3—5 times longer than wide. The ventral margin in the midregion is usually tumid and the dorsal lateral margin is strongly curved. Measurements: W. 150-208u. Distribution: Reported only from.Wayne (Campbell 1886). 26. Closterium moniliferum (Bory) Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. l3(1):289. P1. 18, Figs. 6, 7. This species is 6-8 times longer than wide. The cell wall is colorless and smooth. The curvature is slight to moderate with the ventral margin slightly tumid in the midregion of the cell. The lateral mar- gins taper gradually to the obtusely rounded apices. The terminal vacuoles have about ten rounded gypsum crystals and the 4-8 pyrenoids are always in a row. This species can be separated from 91, Leibleinii by the more bluntly pointed apices and the lesser curvature. Measurements: L. 170-(185)-(225)-(264)-450u; W- 28-(35)' (37)-(40)-72u. Distribution: SLP, Barry, Calhoun, Clinton, Ingham, Oakland, Jackson, also Ionia (Wade 1949), Wayne (Campbell 1886), Macomb (Pieters 189W) and St. Clair (N & A 1932); NLP, Cheboygan (N a A 1932, Welch 19383), Emmet (N a: A 1932); EUP, Chippewa (N & A 1932); WUP, Houghton, Gogebic (2) Marquette, also Houghton (N & A 1932)- 86 27. Closterium calosporum var. brasiliense Boerges. P1. 3, Fig.2. Krieger, 1935. Rabh. Krypt. Flor. l3(1):294. P1. 19, Fig. 8. This variety is typically 12-16 times longer than wide. The cell wall is smooth, colorless or brown, and the curvature is well marked. The midregion of the cell is not tumid and the lateral margins taper gradually to the obliquely truncate apices which have an apical thick- ening (endpores). Specimens from Washtenaw County are placed here reservedly as they seemed somewhat inter- mediate between the typical and the variety. The length was only 11.4 times longer than the width, but the gen- eral configuration of the cells agrees more closely with the variety. They also resembled Cl, Dianae generally, but the narrow width (llu) distinguishes them from this species. Measurements: L. 90-(126)-l95u; W. 5-(ll)-1lu. Distribution: SLP, Washtenaw. New record for Michigan. 28. Closterium dianae Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. l3(1):294. P1. 19, Figs. 9-11; P1. 20, Fig. 1. This species is about 9-12 times longer than wide. The cell is strongly curved with the ventral margin in the midregion straight, or slightly swollen. The lat- eral margins taper sharply to the obliquely truncate apices where the wall has a distinct polar thickening. 87 The cell wall is smooth when young, brownish when older. The terminal vacuoles have 7-20 small gypsum crystals, and each chloroplast has 5-9 pyrenoids. Measurements: L. 150-(157)-(333)-380u; w. 15-(19)-(26)- #Ou. Distribution: SLP, Calhoun, Livingston, Washtenaw, Oak- land, Barry, Berrien, also Washtenaw (West and West 1898) Macomb (Pieters 189A) and Wayne (Campbell 1886); NLP, Crawford, also Cheboygan (N & A 1932); EUP, Alger, Mack- inac, also Delta (N & A 1932); WUP, Gogebic (5), Marquette; Isle Royale (Taylor 1935, Prescott 1941). 29. var. pseudodianae (Roy) Krieger Krieger, 1935. Rabh. Krypt. Flor. l3(1):297. P1. 19, Figs. 16, 17. This variety is relatively longer (14—21 times longer than wide), and much more slender near the apices than the typical. The midregion of the cell is somewhat tumid in some specimens. Measurements: L. 160-(16l)-(176)-312u; W. 10-(10.7)-(15)- 18u. Distribution: SLP, Washtenaw, Livingston, also Oakland (Transeau 1917); NLP, Cheboygan, also Emmet (N & A 1932); EUP, Alger, Mackinac, Schoolcraft, Delta; WUP, Houghton; Isle Royale (Prescott 1937, 1941). All records except the writer's are for 91, pseudodianae, but the writer fel- lows Krieger (1935) in considering it a variety of 91.. Dianae. .‘ Mo: 4'" voc~ x.. .,r (‘D 'r1 30. Closterium littorale Gay Krieger, 1935. Rabh. Krypt. Flor. l3(1):298. P1. 20, Figs. 3-5. This slightly curved species is 9-11 times longer than wide. The ventral margin is straight or somewhat tumid. The margins taper gradually to the rounded or subtruncate apices. The cell wall is smooth and color- less (rarely striated). The terminal vacuoles usually contain a single compound gypsum crystal, and the chloro- plasts each have 3-10 pyrenoids. Specimens from Mack- inac County agree rather well with the description of Ithis species, although the appearance was somewhat more slender and the apices were distinctly narrowly truncate. There is some resemblance to Cl, tumidum but the latter is much smaller. The Michigan specimens are almost iden- tical with Iréhee Marie's (1938) illustration of 9;, siliqua, West and West (this species is considered synon- omous with Cl. littorale by Krieger (1935). Measurements: L. l30-(2A7)-270u; W. 15-(21.5)-25u. Distribution: NLP, Emmet (N a A 1932, Q1. siligua); EUP, Mackinac. 31. glosterium strigosum Breb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):299. P1. 20, Figs. 8-10. This Species is 12-20 times longer than wide. The curvature is slight, and the lateral margins taper grad- ugh ‘ p Iva l“ LL. cei ...-J .A " 'H- 4'" ":r 0'“ 89 ually from a non-tumid midregion to the sometimes in- curved, sharply pointed, or slightly rounded apices. The cell wall is colorless and smooth. The terminal vacuoles have several gypsum crystals, and the chloroplasts each have 3-11 pyrenoids in linear series. Measurements: L. lSO-AlOu; W. lO-20u. Distribution: SLP, Wayne (Campbell 1886), Barry (N & A 1932} 91, peracerosum). 32. var. elegans (G. S. West) Krieger Krieger, 1935. Rabh. Krypt. Flor. 13(1):3oo. P1. 20, Fig. 12. This variety is separated from the typical by the greater tumidness of the ventral margin in the midregion, and the more obtuse or truncate apices. The chloroplasts each have 5-8 pyrenoids in linear series, and the terminal vacuoles contain one or two gypsum crystals. Measurements: L. 150-390u; W. 11-2lu; A. 2-3u. Distribution: SLP, Barry (N & A 1932, El, peracerosum var. elegans); Isle Royale (Prescott 1941). 33. Closterium Lunula (Muell.) Nitszch. Krieger, 1935. Rabh. Krypt. Flor. 13(1):301. P1. 21, Fig. 1; P1. 22, Fig. 1. This large, almost straight, species is 5-8 times longer than wide. The dorsal margin which is curved, and the ventral margin which is almost straight or slightly convex or concave, taper gradually to the broadly rounded 3. ~ .—-,-~ NF. 1 . O i I I o n ‘I . fl . . o 'H . ‘ . . ' o n o ' ' . ~ . . € 0 o o 0 ‘ . . ~ 1 u > . . , . .. 7 .. o h . 1 ~ A I ' 90 or truncate apices. The cell wall is smooth and color- less or rarely striated or punctate, and the terminal vacuoles each contain lO-3O gypsum crystals. The pyren- oids are numerous and scattered. Measurements: L. 248—Aoo-409-(598)-1000u; w. u7-(56)- (64)-(81)-120u. Distribution: Ionia (Wade 1949); NLP, Crawford (2), also Cheboygan SLP, Washtenaw, Livingston, Barry, also (N & A 1932, Welch 1938a); WUP, Gogebic (2), Houghton (2). 34- var. minus West and West Krieger, 1935. Rabh. Krypt. Flor. 13(1):304. P1. 21, Fig. 5. This variety is smaller than the typical and the cell wall has a faint straw color. L. 305—(361)-403u; W. (53)—54-58u. SLP, Barry; Isle Royale (Prescott 1937). Measurements: Distribution: 35. var. intermedium Gutw. Krieger, 1935. Rabh. Krypt. Flor. 13(1):303. Pl. 21, Fig. 3. This variety has a distinctly tumid midregion and 18 5-6 times longer than wide. The apices may be some- what angular and recurved. Measurements: L. 300-660u; W. 47-140u. Distribution: Isle Royale (Prescott 1941). 36- glosterium abruptum. West Krieger, 1935. Rabh. Krypt. Flor. 13(1):306. P1. 21, Fis- 9: P1. 22, Fig. 5-7. 91 This species is 9-14 times as long as wide, has a girdle band, smooth cell wall, a very slight curvature, and a slight tapering of the lateral margins toward the broadly truncate apices. The terminal vacuoles usually have a single compound gypsum crystal, and the chloro- plasts each have 4-6 pyrenoids in a single series. ‘Some forms resemble Cl, tumidum which has a stouter appearance (6-9 times longer than wide) and characteristic swelling in the midregion of the cell. Measurements: L. lOO-(l24)-(128)-240-246u; W. 11-(13)- (15)-(17.4)-l9u; A. 5-8.6u. Distribution: SLP, Livingston; NLP, Roscommon, Presque Isle, also Presque Isle (Taft 1939); WUP, Gogebic (3). 37. Closterium.tg§gn_ West Krieger, 1935. Rabh. Krypt. Flor. 13(1):310. P1. 23, Figs. 4, 5. This species is 13-30 times longer than wide. The lateral margins are subparallel and straight for about two-thirds the length in the midregion, and then taper gradually into slightly incurved subtruncate apices. The dorsal margin is often slightly concave in the mid- region. The cell wall is smooth and colorless (some- times brownish). The terminal vacuoles contain several gypswm crystals and the chloroplasts each have 5-7 pyren- oids arranged in a linear series. Measurements: L. 163-(277)-(321)-330u3 W- 8-(10-5)-(12- 201.1; A. 6-(6.5)-9u. m n “1 .4 A In .H U- —- 92 Distribution: SLP, Calhoun; NLP, Cheboygan (N & A 1932); EUP, Delta, Schoolcraft; WUP, Houghton, Gogebic. 38. Closterium gracile Breb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):310. P1. 30, Figs. 7-9. This very slim species is 20-50 times longer than wide. The lateral margins are parallel in the midregion of the cell, but taper near the poles into truncate, inwardly curved apices. The cell wall is usually color- less and smooth. The pyrenoids (5-7) are arranged in a linear series in each chloroplast, and the terminal vac- uoles have from 1-4 gypsumcrystals. Measurements: L. 90-(2SO)-275u; W. 4-(5)-8u; A. 2.5-3.5u. Distribution: SLP, Barry, Berrien also Macomb (Pieters 1894); NLP, Cheboygan (N a A 1932); EUP, Chippewa; WUP, Houghton, Gogebic. 39. var. elongatum West and West Krieger, 1935. Rabh. Krypt. Flor. 13(1):311. P1. 30. Figs. 10, 11. This variety is 50-75 times longer than wide. Measurements: L. 275-(277)-(336)-485u; W. 3-(4.2)-5-(6)u. Distribution: SLP, Barry, Calhoun, also Ionia (Wade 1949); NLP, Crawford, also Macosta (N & A 1932); Isle Royale (Taylor 1935). 40' glosterium.macilentum. Breb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):312. P1. 23, F188 0 6-80 V W’— '- —7fi_ i, " _. - ' O . . . O n 1 . 7 c ’ I u I . \ o O . O . . o ‘ 4 \ n ‘ . ‘ ,. o - Q o . . e . . l O I O a o . ’ b o ' « i . \ i s .9 4 o . , ’ . . . n . . ‘ o O . . ‘ . ' . 1' r | . ‘ A H I . . u ‘ . . . . l O C . ’ . ‘ . c ‘ \ o . . . , . . . o . x V g . . . a t I O « D Q ' \ i C I ' a n c , u ~ u C A I I . . D I A I . . ' U . . v . u . ; ~ 1 o . - . ' - ‘ ~ . V a 5 f . . ~ ‘ v r . o ' .1 .1 . - - o - \ . ‘ n . - | . . ' ' a e ‘ - O O r'_l . m (‘9' (f L—.—‘ 93 This species is 25-35 times longer than broad, has a girdle band, a slight curvature (especially in the ter- minal region), and lateral margins which are parallel in the middle third of the cell, but which above taper to the slightly obliquely truncate or obtusely rounded apices. The terminal vacuole has two to ten gypsum crystals, and the chloroplasts each have 6-12 pyrenoids in a linear series. Measurements: L. 260-800u; W. 11-25u; A. 5-7u. Distribution: SLP, Macomb (West and West 1898); NLP, Cheboygan (N & A 1932). 41. Closterium acerosum (Schrank) Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):314, P1. 23, Figs. 11, 12; P1. 24. Fig. 1. This species is 7-13 times as long as wide, very slightly curved or almost straight. The dorsal margin which is slightly curved, and the ventral margin which is almost straight or slightly convex, taper gradually to the broadly or truncately rounded apices. The cell wall often appears colorless and smooth, but examples with brownish and finely striated.walls have been found. The terminal vacuoles have numerous gypsum.crystals and each chloroplast has 6-16 pyrenoids arranged in a regular or irregular longitudinal linear series. Measurements: L. 250-(320)-(336)-790u; V. (22)-25-60u. Distribution: SLP, Shiawassee, also Ionia (Wade 1949), a.“ K: 94 Macomb (Pieters 1894) and Branch, Hillsdale, Jackson, Lenawee (N & A 1932), Wayne (Campbell 1886), Van Buren (Transeau 1917); EUP, Chippewa (N & A 1932); WUP, Houghton (N a A 1932). 42. var. angolense West and West Krieger, 1935. Rabh. Krypt. Flor. 13(1):317. P1. 24, Fig. 2. This variety is longer than the typical (16-23 times longer than wide). The cell wall is smooth and colorless, and the apices are rounded. Measurements: L. 650—915u; W. 30-40u. Distribution: NLP, Cheboygan (N & A 1932, Welch 1938a). 43. var. elongatum Breb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):318. P1. 24, Fig. 5. This variety is relatively longer (15-33u) than the typical. The cell wall may be colorless or brownish, striated or punctate. Measurements: L. (498)-500-(563)-lOOOu; W. (28-29-(30)- 54u. Distribution: SLP, Calhoun, also Ionia (Wade 1949); NLP, Cheboygan, Mecosta (N & A 1932)~ 1M» Closterium_lanceolatum Kuetz. Krieger, 1935. Rabh. Krypt. Flor. 13(1):319- P1. 24, Figs. 9, 10. This species, which is slightly or not at all curved, 95 is 5-10 times longer than wide. The dorsal margin which is convex, and the ventral margin, which is straight or slightly convex, taper gradually to the acutely rounded apices. The cell wall is smooth and colorless, and the terminal vacuoles have about ten gypsum crystals. There are 6-8, sometimes up to 12, pyrenoids in each chloroplast. Measurements: L. 200-540u; W. 28-79u. Distribution: SLP, Ionia, Newaygo; NLP, Cheboygan, Emmet, Newaygo; all records by Nichols and Achley 1931; also Cheboygan (Welch 1938a). 45. (Closterium Pritchardianum. Archer Krieger, 1935. Rabh. Krypt. Flor. 13(1):321, P1. 25, Figs. 1-4. This species is 8-25 times longer than wide. The general curvature of the cell is slight, with the dorsal margin slightly curved, and the ventral margin concave or almost straight. The apices are narrowly truncate, and often recurved. The cell wall is finely striated, the striae being composed of fine punctations. The ter- minal vacuoles each have many gypsum crystals, and each chloroplast has 7-16 pyrenoids in linear series. Measurements: L. 300-(452)-810u3 W. 27-(34)-54u; A. 6-8u. Distribution: SLP, Washtenaw, also Jackson (N & A 1932); NLP, Cheboygan (N & A 1932). 46. Closterium praelongum. Breb. Pl. 2, Fig. 2. Krieger, 1935. Rabh. Krypt. Flor. 13(1):234, P1. 25, Figs. 7, 8. 96 This slender species‘is 25-45 times longer than wide. The general curvature is slight. The dorsal mar- gin.which is slightly convex, and the ventral margin which is parallel or slightly concave, taper gradually to the obtuse or truncately rounded apices that are slightly recurved. The cell wall is colorless or brown- ish, and may be smooth or striated (15 per lOu). Each chloroplast has 8-23 pyrenoids, and each terminal vacuole has 1-2 compound gypsum crystals. Measurements: L. 380-(623)-885u; W. 11-(17)-26u; A. 4-6.5u. Distribution: SLP, Washtenaw; WUP, Iron, Marquette, Men- ominee, Houghton. New records for Michigan. 47- Closterium didymocotum Corda Krieger, 1935. Rabh. Krypt. Flor. 13(1):325. P1. 26, Figs. 1, 2. The limits of this species are somewhat poorly de- fined. West and West (1904) indicate that the walls may be striated but are usually smooth. Gronblad (1919) in- cludes only those organisms that possess striae and girdle bands. Krieger (1935) follows Gronblad's ideas but his illustrations and description of this species indicate a somewhat more stout and less tapered cell than Taylor's (1935) specimens which are very much attenuated toward the'apices. The writer includes here, under 91, gigymocotum, those Michigan specimens which are 8-10 tunes longer than 96 This slender species is 25-45 times longer than wide. The general curvature is slight. The dorsal mar- gin.which is slightly convex, and the ventral margin which is parallel or slightly concave, taper gradually to the obtuse or truncately rounded apices that are slightly recurved. The cell wall is colorless or brown- ish, and may be smooth or striated (15 per lOu). Each chloroplast has 8-23 pyrenoids, and each terminal vacuole has 1-2 compound gypsum crystals. Measurements: L. 380-(623)-885u; W. 11-(17)-26u; A. 4-6.5u. Distribution: SLP, Washtenaw; WUP, Iron, Marquette, Men- ominee, Houghton. New records for Michigan. 47. glosterium didymocotum Corda Krieger, 1935. Rabh. Krypt. Flor. 13(1):325. P1. 26, Figs. 1, 2. The limits of this species are somewhat poorly de- fined. West and West (1904) indicate that the walls may be striated but are usually smooth. Gronblad (1919) in- cludes only those organisms that possess striae and girdle bands. Krieger (1935) follows Gronblad's ideas but his illustrations and description of this species indicate a somewhat more stout and less tapered cell than Taylor‘s (1935) specimens which are very much attenuated toward the apices. I The writer includes here, under 91, didympcotwm, those Michigan specimens which are 8-10 times longer than 97 wide, and which possess short, irregular, longitudinal striae-like strips. Girdle bands were not seen, pro- bably because the cells were young and had not divided. Measurements: L. 391-(397)-628u; W. 44-(48)-(50)-61u; A. 21-25u. Distribution: Undoubtedly most of the records here are those of 91, Eaillyanum (in sensu Krieger). SLP, Barry, Livingston, also Muskegon (Transeau 1917); NLP, Crawford, Emmet, also Cheboygan (N a A 1932; Welch 1936b): EUP, Chippewa, also Chippewa (N & A 1932). 48. var. glabrum Borge Pl. 1, Fig. 12. Krieger, 1935. Rabh. Krypt. Flor. 13(1):326. P1. 26, Fig. 4. This variety has the same proportions as the typical (8-10 times longer than wide) but the cell wall is smooth. Measurements: L. (355)-382-(386)-626u; W. (44)-(46)-48- 60u. Distribution: NLP, Roscommon; EUP, Schoolcraft. New re- cords for Michigan. 49. Closterium Baillyanum Breb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):327. P1. 26, Figs. 7, 8. This slightly curved species has often been confused with.gl, didympcotum.(see discussion under the latter). According to Krieger,(1935), this species is 9-12 times longer than wide. The dorsal margin is convex, the cen- 98 tral margin mostly straight, sometimes concave. The apices are broadly truncate (with rounded angles), and occasionally slightly recurved. The cell wall is color- less when young, brownish when older. The punctations in the cell wall are more distinct on the darker brown, thickened apices. The chloroplasts each have 5-8 pyren- oids, and the terminal vacuoles each have several gypsum crystals. Measurements: L. 250-(462)-607u; W. 24-(44)-58u; A. 17- 23u. Distribution: WUP, Houghton, Gogebic, Marquette; Isle Royale (Prescott 1941). 50. var. alpinum (Viret) Gronbl. fa. P1. 1, Fig. 11. Krieger, 1935. Rabh. Krypt. Flor. 13(1):328. P1. 26, Fig. 9. This variety is characteristically more slender (12- 14 times longer than wide) than the typical. The ven- tral margin is slightly concave, and the cell wall is clearly punctate. A few Specimens from Schoolcraft County were relatively longer (about seventeen times longer than wide) than either the typical or var. alpinum. It is placed here questionably, because of the agreement in greater curvature and the proportionately narrow and longer cells, although this variety has only been re- ported from mountainous areas of Europe. Measurements: L. 380-(500)-48u; W. (30)-32-48u; A. (16)-l9u. Distribution: EUP, Schoolcraft. New record for Michigan. 3 mm :—= 2 11 99 51. Closterium.turgidum. Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. 13(1): 330. P1. 27, Figs. 1, 2. This large, slightly curved species is lO-l3 times longer than wide. The dorsal lateral margin, which is slightly curved, and the ventral lateral margin, which is straight or slightly concave in the midregion of the cell, taper gradually to the angularly rounded, usually distinctly recurved apices. The cell wall is brownish in color, and finely striated (8-14 per lOu). The striae are often reduced into rows of punctations especially near the apices. The chloroplasts each have lO-lS py— renoids, and the terminal vacuoles each have numerous gypsum crystals. Measurements: L. 560-(684)-940u; W. 45-(64)-86u; A. 15— 19u. Distribution: NLP, Crawford; Isle Royale (Prescott 1937). 52. var. giganteum Nordst. Krieger, 1935. Rabh. Krypt. Flor. 13(1):332. P1. 27, Figs. 5, 6. This variety is 7-12 times longer than wide, and usually much longer than the typical. The pyrenoids are more numerous (80-90 in each semicell) and are usually scattered. Measurements: L. 590-1500u; W. 58-138u; A. 18.5-33u. Distribution: NLP, Cheboygan (N & A 1932, 91, subturgidum). 100 53. Closterium.subscoticum Gutw. P1. 1, Fig. 10. Krieger, 1935. Rabh. Krypt. Flor. 13(1):333. P1. 27, Figs. 10-12. This species typically is 17-26 times longer than wide. The girdle bands are present and the cell wall which is punctate-striate, may be either colorless or brownish. The curvature of the cell is slight, with the lateral margins parallel in the midregion of the cell, but above are very slightly tapered towards the truncate apices. The terminal vacuoles each have a single compound gypsum crystal and the chloroplasts each have 8-11 pyrenoids. A few specimens from Livingston County were only 12-13 times longer than wide, but the striations were very fine and interrupted. They agree with the measurements of C1, intermedium but the type of cell wall markings place them questionably in 91, subsco- tiggm, 91, striolatum may have reduced striolations but is always much wider. Measurements: L. (174)-182-(192)-400u; W. 11-(15)-15u; A. 8-llu. Distribution: SLP, Livingston. New record for Michigan. 54. glpsterium.luncidum.var. elongatum. Roy and Biss. Pl. 2, Fig. 1. Krieger, 1935. Rabh. Krypt. Flor. 13(1):335. P1. 28, Fig. 4. This organism is 35-45 times longer than‘wide, and has a pale yellow to brown cell wall that is striated 101 (14-20 per lOu). The lateral margins are parallel in the midregion of the cell, but taper gradually to the trun- cate apices which have slightly rounded angles, and apical thickenings. The curvature is especially reflected by the inward bending near the poles. The terminal vacuoles contain one large gypsum crystal or several small ones, and the chloroplasts each have 4-9 pyrenoids. The Michigan specimens from Calhoun County had a less obvious polar curvature and a more slight curvature of the entire cell. Measurements: L. 295-(370)-473u; W. 8.5-(10.5)-13u. Distribution: SLP, Calhoun. New record for Michigan. 55. Closterium intermedium Ralfs. Krieger, 1935. Rabh. Krypt. Flor. 13(1):335. P1. 28, Figs. 5, 6; P1. 29, Fig. 8. This slightly curved species is 6-15 times longer than wide, and possesses a girdle band. The cell walls are yellow to yellowish brown, and are distinctly striated (6-10 per lOu); the lateral margins are parallel in the middle part of the cell, but taper above gradually to the slightly incurved broadly truncate apices. The apices usually have an apical thickening and the terminal vacuoles have either a single large or several small gyp- sum.crystals. There are 5-7 pyrenoids in each chloroplast. Measurements: L. 75-(370)-470u; W. l4-25-(26)u; A. 6-8u. Distribution: SLP, Barry, Washtenaw (2), Berrien; NLP, Crawford, also Cheboygan (N a A 1932); EUP, Alger, Delta, 102 Schoolcraft, Mackinac, also Mackinac (Transeau 1917); WUP, Houghton, Gogebic; Isle Royale (Prescott 1937). 56. var. hibernicum. West Krieger, 1935. Rabh. Krypt. Flor. 13(1):336. P1. 28, Fig. 7. This variety is separated from the typical by the shape of the cell. The lateral margins are parallel and straight in the midregion of the cell, but become rather suddenly incurved in the more apical portions. Measurements: L. 200-(340)-384u; W. 14-(23.5)-26u. Distribution: EUP, Mackinac; Isle Royale (Prescott 1941). 37. Closterium striolatum Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):337. P1. 28, Figs. 8, 9; P1. 29, Fig. 9. This species is 8-12 times longer than wide, has a girdle band, and a cell wall that is variably striated (5-10 per lOu, often anastomosing or becoming punctate near apex), and lateral walls that are parallel or slightly concave in the midregion part of cell, but taper- ing gradually to the apices which are truncate with rounded angles. The end walls and angles of the apices may be thickened, causing the apices to appear slightly swollen. The terminal vacuoles usually have one large compound gypsum crystal, although there can be several smaller additional crystals. Each chloroplast has 5-9 pyrenoids. This species can be separated from.g, intermedium by the Proportionately wider cells. . ' I » . . . . C . I o I C . , . c _. .. ,vo . C _ . D l C o e . _ - . a . I A . O ' n a ‘ ' I . .. . 1 . _ t 5 i t . I Q i O V 7 . ‘ o . . 103 Measurements: L. l80-(234)-(262)-540u; W. (26)-(27)- 52u; A. lO-lSu. Distribution: SLP, Barry, Washtenaw (2), also Berrien (Transeau 1917); NLP, Cheboygan (N & A 1932); EUP, Mack- inac (Transeau 1917, N & A 1932); WUP, Marquette, Houghton; Isle Royale (Prescott 1941). 58. Closterium ulna Focke Pl. 2, Fig. 5. Krieger, 1935. Rabh. Krypt. Flor. 13(1):341. P1. 29, Figs. 1-4. This slightly curved species is 16-25 times longer than wide, has a girdle band, a colorless or pale yellow striated cell wall (lo-12 per lOu), and with lateral mar— gins almost parallel, but very slightly attenuated to broadly rounded truncate apices. The terminal vacuoles generally have one large gypsum crystal, and the chloro-’ plasts each have 6-19 pyrenoids. Measurements: L. 170-(240)-500u; W. lO—(l5)—23u; A. 7.5-13.5u. Distribution: NLP, Roscommon, EUP, Alger. New records for Michigan. 59- Closterium.Braunii Reinsch P1. 2, Figs. 7, 8. Krieger, 1935. Rabh. Krypt. Flor. 13(1):343. P1. 30, Figs. 1, 2. This species is 16-22 times longer than wide. The dorsal margin is slightly curved, the ventral margin slightly concave. The lateral margins are parallel in o c . - I C U . . - . , . c C o - V . e . " o . O s o o , O ‘ . v W. - o . . , . _ - . . . . . . o . I . ’ ' ' o . . u , . . o 0 . . . o I . _ I I . a ’ . 104 the midregion and taper almost inperceptibly for the greater length of the cell, then taper sharply to the truncate, often slightly recurved apices. The brownish cell wall is distinctly marked by 4-6 longitudinal double rows of punctate striations. In between each double row, the cell wall is irregularly punctate. The chloroplasts each have 14-16 pyrenoids, and the terminal vacuoles each have about twenty gypsum crystals. The Michigan specimens from Houghton County appear identical With g1. attentuatum var. sculptum Nordst. which Krieger (1935) places under 913 Braunii. Measurements: L. 450-(666)-800u; W. 25-(44)-61u. Distribution: WUP, Houghton. New record for Michigan. 60. Closterium attentuatum Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):344. P1. 30, Figs. 3, 4; P1. 31, Fig. 1. This species is 11-16 times longer than wide, and slightly curved. The lateral margins taper gradually from the non-tumid midregion to below the apices where there is an abrupt narrowing to form apices that are truncately obtuse, but conical. The cell wall is brownish, and finely striated (8-9 per lOu), the striae sometimes reduced to punctations near the apices. The terminal vacuoles have many gypsum crystals and there are 6-9 pyrenoids arranged in a linear series in each chloroplast. Measurements: L. 360-580u; W. 28-67u; A. 6-8u. Distribution: NLP, Newaygo (N & A 1932). 105 (ha Closterium Ralfsii Breb. fa. P1. 3, Fig. 5. Krieger, 1935. Rabh. Krypt. Flor. 13(1):345. P1. 31, Figs. 2, 3. This species is 6-10 times longer than wide. The dorsal lateral margin is slightly curved throughout, whereas the ventral margin is convex in the midregion of the cell. The lateral margins taper sharply to the trun— ‘cate pOles that have an apical thickening in the wall. The cell wall is brownish and striated (7-9 per lOu). The striae become reduced into conspicuous pores near the apices. The terminal vacuoles have about ten gypsum crystals and each chloroplast has 6-9 pyrenoids. A few specimens from Delta County were slightly narrower than the typical measurements. The middle tumidness did not occupy as much of the cell length as in most typical expressions. Measurements: L. 3oo-(368)-610u. w. (37)-40-62u; A. 9-10u. Distribution: EUP, Delta. New record for Michigan. 62. var. hybridum Rabh. Krieger, 1935. Rabh. Krypt. Flor. 13(1):347. P1. 31, Figs. 4,5. This variety is proportionately narrower than the typical (11-18 times longer than.wide). The cell wall is more finely striated (9-10 per lOu), and the chloro- plasts each have up to twenty one pyrenoids. 106 Measurements: L. 300-(5l3)-(5l7)-770u; W. 24-(36)~40- (45)u; A. 5-10u. Distribution: SLP, Livingston, Washtenaw, Barry, also Macomb (West and West 1898), and Washtenaw (N & A 1932, _C_l_. decorum Breb.); NLP, Cheboygan (N a A 1932, _c__1_. 92.9.- 9_r_15_m_ Bréb); EUP, Delta; WUP, Gogebic, Houghton, also Houghton (N & A 1932, El, decorum Breb.); Isle Royale (Prescott 1941). 53. Closterium lineatum. Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):349. P1. 32, Figs. 1, 2. This narrow species is 16-26 times longer than wide. The lateral margins are straight and parallel in the mid- region of the cell, but taper gradually beyond into slightly incurved truncate apices. The color of the cell wall is brown, and the striae number 6-10 per lOu. The terminal vacuole contain 4-10 (rarely 1) gypsum crystals, . and the chloroplast has 9-12 (rarely up to 15) pyrenoids in a linear series. Measurements: L. 300-(516)-768u; W. 13-(20)-36u; A. 4-10u. Distribution: SLP, Barry (2), also Macomb (Pieters 1894) and Allegan (Transeau 1917); NLP, Cheboygan (N & A 1932); EUP, Delta. at» var. ggstatum ‘Wolle Pl. 2, Fig. 4. Krieger, 1935. Rabh. Krypt. Flor. 13(1):351. P1. 32, Figs. 4, 5. 107 Typically, this variety is 25-28 times longer than wide. The possession of distinct costae (3 per lOu) sep- arates this organism from the typical. Specimens from Barry and Schoolcraft Counties were only about seventeen times longer than wide, and agree well with similar speci- mens reported by Irenee-Marie (1938) from Canada. Measurements: L. 420-(559)-770u; W. 19-32-50u. Distribution: SLP, Barry; EUP, Schoolcraft. New record for Michigan. 65. Closterium Kuetzinggi Bre’b. Krieger, 1935. Rabh. Krypt. Flor. 13(1):351. P1. 32, Figs. 8, 9. The cells of this species are 20-30 times longer than wide. The median part of the cell is fusiform with the almost equally convex lateral margins converging gradually into long setaceous extremities that posses slightly incurved and swollen apices. The cell wall is brownish with 8-11 striae per lOu. The terminal vacuoles contain 2-10 gypsum crystals, and the chloroplasts each have 4-7 pyrenoids in a linear series. Measurements: L. 270-(426)-540u. W. 14-(17)-27u. Distribution: SLP, Barry (3), Calhoun, Washtenaw (2), also Hillsdale, Washtenaw (N & A 1932); NLP, Crawford, also Macosta (N a A 1932); EUP, Schoolcraft, Delta, also Mackinac (N & A 1932, Transeau 1917), Luce (N & A 1932), and Schoolcraft (Transeau 1917); WUP, Gogebic, also Hough- ton (N a A 1932). F 108 66. Closterium rostratum Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):354. P1. 33, Figs. 1-3. . This species is 11—16 times longer than wide. The median region of the cell is fusiform with the ventral lateral margin much more strongly convex than the dorsal lateral margin. The lateral margins taper gradually into relatively short setaceous extremities which possess slightly incurved obtuse, slightly dilated apices. The cell wall is brownish and striated (about 10 per lOu). The terminal vacuoles possess 6-14 gypsum crystals, and 3-5 pyrenoids are arranged linearly in each chloroplast. Measurements: L. l90-(330)-530u; W. l8-(2l)-32u; A. 3-5u. Distribution: SLP, Barry, Washtenaw, also Wayne (Campbell 1886), Macomb, Lake St. Clair Pieters (1894) and Oakland (Transeau 1917); NLP, Cheboygan (N & A 1932); EUP, Delta, Mackinac; WUP, Gogebic. 5?. ggpsterium setaceum Ehrenb. Krieger, 1935. Rabh. Krypt. Flor. 13(1):356. P1. 33, Figs. 8-10. This species is 25-40 times longer than wide. The median part of the cell body is fusiform with both lateral margins converging relatively abruptly into long narrow setaceous extremities that are slightly incurved near the obtuse apices. The cell wall is colorless or brownish, and finely striated (11-12 per lOu). The terminal vacuoles 109 contain three or four gypsum crystals, and the two to three pyrenoids are in linear series in each chloroplast. The body of the cell is relatively small in proportion to the length of the setaceous extremities. El, Mostratum and.gl, Kuetzingii are similar to this species, but have relatively larger bodies in proportion to the length of the setaceous extremities. Measurements: L. 150-(310)—600u; W. 6-(lO)-l3u; A. 1.4u. Distribution: SLP, Ingham, Barry (2), Washtenaw; NLP, Cheboygan, Emmet; EUP, Chippewa, Alger, Mackinac; WUP, Gogebic (3); Isle Royale (Prescott 1937). 68. ggpsterium costatum Corda Krieger, 1935. Rabh. Krypt. Flor. 13(1):358. P1. 34, Figs. 1-3. This species is about 6-10 times longer than wide and possesses girdle bands which are not always recog- nizable. The cell wall has well-develOped, widely spaced costae (1-2 per lOu) and the lateral margins taper grad- ually to the sharply truncate apices. The walls at the apices are thickened so that the poles appear angularly rounded. The terminal vacuoles possess usually one large 8Ypsum crystal, but occasionally there may be numerous small ones. The cell wall is brownish with the poles often more darkly colored. There are 6-12 pyrenoids in each chloroplast. Measurements: L. 200-(305)-550u; W- 28-(37)70u. 110 Distribution: SLP, Barry (2), Livingston, also Wayne (Campbell 1886); NLP, Roscommon, Emmet, also Cheboygan (N a A 1932); EUP, Delta, Schoolcraft (2); WUP, Gogebic, Marquette; Isle Royale (Prescott 1937). 69. var. subcostatum (Nordst.) Krieger Pl. 3, Fig. 3. Krieger, 1935. Rabh. Krypt. Flor. 13(1):360. P1. 34, Fig. 6. This variety is separated from the typical by the smaller lengthawidth ratio (4-7 times longer than wide). The midregion of the semicell may be slightly swollen, ‘1 the apices are roundly truncated and the costae may be more closely arranged (4-5 per lOu). Michigan specimens were slightly broader than the original measurements of this variety. Measurements: L. 232-(365)-377u; W- 31-49-(54)- Distribution: SLP, Barry; EUP, Schoolcraft. New records for Michigan. 70. var. Westii Cushman P1. 2, Fig. 6. Krieger, 1935. Rabh. Krypt. Flor. 13(1):361. P1. 34, Fig. 8. This variety is more slender (10—11 times longer than wide) than the typical and the curvature is slightly greater. Measurements: L. 230-400u; W- 23-41u. Distribution: WUP, Gogebic (2). New record for Michigan. 71. 72. 111 Closterium angustatum Kuetz. Krieger, 1935. Rabh. Krypt. Flor. 13(1):363- P1: 35: Figs. 2-4. This species is usually about 12-18 times longer than broad. The girdle bands or transverse wall markings are present and the cell wall has well-developed (ribs) costae (2 per lOu) that may be somewhat spirally arranged. The curvature is slight with the lateral margins parallel in the midregion of the cell and tapering very slightly to the usually subcapitate apex. The terminal vacuoles have numerous (13-20) gypsum crystals, and the chloro- plasts each have 5-10 pyrenoids. Measurements: L. 250-(559)-650u; W. l6-(17)-(23)-35u. Distribution: SLP, Barry; NLP, Cheboygan (N & A 1932); EUP, Schoolcraft, also Mackinac (Transeau 1917); WUP, Houghton; Isle Royale (Prescott 1941). glosterium Cynthia De Not. Pl. 3, Fig. l. Krieger, 1935. Rabh. Krypt. Flor. l3(1):265. P1- 35, Figs. 6-10. This species is about 8-10 times longer than wide, has a girdle band, a pale yellow or light brown cell wall that is striated (6-9 per lOu), a marked curvature, and lateral margins gradually tapering toward the rounded apices. The terminal vacuoles usually contain one large SYPBum.crysta1. This species has a general resemblance to El, Archerianum but is usually smaller, and has more broadly rounded apices. "XJ 112 Measurements: L. 73-(122)-l80u; W. 9-(15)-22u. Distribution: WUP, Houghton. New record for Michigan. 73. var. Jenneri (Ralfs.) Krieger Krieger, 1935. Rabh. Krypt. Flor. 13(1):366. P1. 36, Fig. 2. This variety is separated from the typical on the basis of the colorless or brown cell wall. The girdle band has not been shown in many illustrations according to Krieger (1935). All the Michigan specimens from Schoolcraft County did not possess a girdle band, and were slightly longer than originally described. Measurements: L. 43-110-(124)u; W. 7-(11.5)-18u. Distribution: NLP, Cheboygan (N & A 1932); EUP, School- craft (2). 74. var. robustum (G. S. West) Krieger P1. 1, Fig. 13. Krieger, 1935. Rabh. Krypt. Flor. 13(1):368. P1. 36, Figs. 5, 6. This variety is separated from the typical on the basis of the stouter proportions, the cells being only 5-6 times longer than wide, and having the apices very broadly rounded. Measurements: L. 42-(70)-80u; W. 8.8-(ll)-14u. Distribution: SLP, Calhoun. New record for Michigan. 75- C_losterium Archerianum Cleve Krieger, 1935. Rabh. Krypt. Flor. 13(1):368. P1. 36, Figs. 7-8. . ‘ I A . I . o a o o , o . r A , . : ,I ~ . . . . - . _ - . o o O c . . _ - - o . o O ' ‘ I . . , . ‘ 4 I l O . . o . n c ‘ - . _ -- .- c a -. o i . I) 113 This Species is about 10-11 times longer than wide, has a girdle band, a brown or yellow cell wall that is striated (5-6 per lOu), a marked curvature and lateral margins gradually tapering toward the rounded apices. The terminal vacuoles have single large gypsum crystals and the chloroplasts each have 5-7 pyrenoids. Measurements: L. (l69)-175-(234)-300u; W. l6-(23.4)-30u. Distribution: SLP, Barry; NLP, Emmet, also Cheboygan (N a A 1932); Isle Royale (Prescott 1941). 8. SPINOCLOSTERIUM (Closterium cuspidatum Bailey) Bernard 1909 Cells broadly crescent-shaped with a strong curvature; lateral margins, tapering gradually to the broadly rounded apices each of which bear a single strong spine. Each semi- cell with a terminal vacuole and a longitudinal ridged chloro- plast; pyrenoids arranged in three or four irregular series. Zygospore unknown. 1” Spinoclosterium cuspidatum (Bailey) Hirano Irenee-Marie, 1952, Le. Nat. Canad. 79(1):33, P1. 1, Figs. 14-15. This is the only species of the genus Spinoclosterium and possesses the characteristics named above. Transeau (1917) reported the occurrence of this organism (as Elga- terium cuspidatum Bailey) from Muskegon County. Krieger (1935) considers Bailey's original form as a Peridinium 0yet, although Wolle considers it a species of Tetraedron 114 and Rabenhorst, a species of Qphiocytium (Wolle 1887). The writer believes that the presence of the terminal spines is sufficient evidence to separate this organism from the genes} Closterium as has Hirano (1949). Bernard's (1909) use of the name Spinoclosterium is thus the proper designation of the genus. However, Bailey's species name gpspidatum must be used because of the International Rules of Botanical Nomenclature. Measurements: L. 150-165u; W. 50u. Sp. 15u. Distribution: SLP, Muskegon (Transeau 1917). 2. var. spinosum Prescott Prescott, 1937. Pap. Mich. Acad. 801., Arts and Letters. 22:203, P1. 19, Figs. 1-3. This variety can be separated from the typical by the slight dilation of the poles, especially upon the dorsal margins. The original specimens also possessed scattered concretions on the older cell wall. The shape of the cell is also different with the width of the var- lety being proportionately greater than in the typical (as shown by'Wolle 1887). Measurements: L. 140-148u; W. 58-62u; Sp. 4.5-11.5u. Distribution: SLP, (Unknown locality by Taft according to Prescott (1940); NLP, (Unknown locality by the writer); Isle Royale (Prescott 1937)- 115 9. PENIUM Breb. 1844 Cells usually cylindrical, of variable length, always longer than wide, sometimes with a median constriction, usu- ally attenuated near the apices which are mostly broadly rounded, truncate, or truncately rounded. Cell wall color- less to brownish, ornamented with longitudinal striae or punc- tate, and with a demarcation line between the two semicells. Chloroplasts, axial, one or more in each semicell, with radi- ating plates that extend to the cell wall. Pyrenoids, when Single, centrally placed, when more than one, in an axial linear series. Zygospores spherical to rectangular, with walls generally smooth. Key to Species of Penium 1- Cell wall with longitudinal striae . 5 1- Cell wall with irregularly arranged rows of punctations or with irreg- ular punctations . . . . . . . . . 2 2. Cell walls with irregular rows of punctations . . . . . . . (l) P, margaritaceum 2. Cell wall irregularly and densely punctate . . . . . . 3 3. Lateral margins somewhat invaginate a short distance below the apex causing the apices to appear slightly dilated; L. 19-69u3 W. 6-l4u . . . . . . . . . . . . . (2) P, gxlgggm' 3° Lateral margins not invaginate a 4 short distance below the apex . . 116 4. Cell width 8-2lu; cell wall not medianly constricted . . (3) g, cylindrus 4. Cell width 20-31u; cell wall usually with a light median constriction . . . . . . . . (4) P. rufescens Cell wall punctate between longitud- inal striae, cell length over 77u. (5) P. spirostriolatum Cell wall not punctate between long- itudinal striae, cell length under 791.1 0 o o e o o o o o o o o o o 6 6. Girdle band never present; longitudinal striae often difficult to see . . . . . . (6) P, phymatosporum 6. Girdle band usually present; longitudinal striae usually distinct . . . . . . . . . (7) £3 pplymorphum Penium margaritaceum (Ehrenb.) Breb. Krieger 1935. Rabh. Krypt. Flor. l3(1):230. P1. 10, Figs. 2-4. This species is characterized by cylindrical cells, three to thirteen times longer than wide, with broadly rounded or almost truncate poles. The cell wall is orna- mented with punctations arranged in slightly irregular longitudinal rows. West and West (1904), G. M. Smith (1924), Irénee-Marie (1938) state the surface is granular but the writer agrees with Krieger (1935) that the wall is punctate.and the "granules" are merely extrusions of mucilage. The cell wall is reddish-brown and also usu- ally constricted in median portion. The chloroplasts of which there are one or two in each semicell, have the longitudinal ridges radiating to the cell walls. The py- 117 renoids (one or two per chloroplast) are placed in a linear central row. Measurements: L. 60-(65)-(127)-230u; W. 13-(19.3)-(21)- 30u. Distribution: SLP, Berrien, also Berrien (Transeau 1917), and Macomb (Pieters 1894); EUP, Schoolcraft, also Luce (N & A 1932); WUP, Gogebic. 2. Penium exiguum W. West Krieger, Rabh. Krypt. Flor. l3(1):233. P1. 10, Figs. 7-10. This species is small of a very variable length, usually three to six times longer than wide. The cylin- drical cell, often dilated at the apices, commonly has a median constriction. The cell wall is irregularly punc- tate. One to three pyrenoids are present in each semi- cell and frequently terminal vacuoles with gypsum crystals are present. Measurements: L. l9-69u; W. 6-l4u. Distribution: NLP, Cheboygan (Taft 1939). 3- Penium gylindrus (Ehrenb.) Breb. Krieger 1935. Rabh. Krypt. Flor. l3(1):234. P1. 9, Figs. 9-12. This small species is cylindrical, without a median constriction, and usually two to four (rarely six) times longer than wide. The lateral margins are not tapered except at the apices which are broadly rounded to trun- cate. The cell wall is irregularly but densely punctate, 118 with older cell walls becoming brownish. One or two chloroplasts, each with one or two central pyrenoids are present in each semicell. Measurements: L. 30-58u; W. 8-2lu. Distribution: NLP, Presque Isle, also Cheboygan (N & A 1932, Welch 1936b); WUP, Baraga (N a A 1932). Penium rufescens Cleve. Krieger 1935. Rabh. Krypt. Flor. l3(1):240. Figs. 13, 14. P1. 10, This species is broadly cylindrical and about two to two and one-half times longer than wide. The cell wall is reddish brown or colorless, and densely but ir- regularly and finely punctate. The apices are usually broadly rounded, the lateral margin has a slight median constriction and sometimes a slight compression above the median constriction. A central pyrenoid is present in each half cell. Measurements: L. 50-(59)-81u; W. 20-24.5)-3lu. Distribution: EUP, Schoolcraft; WUP, Marquette (Pres. & Mag. 1935); Isle Royale (Prescott 1937, g, chrysoderma Borge). 5‘ EEEEBE;Splrostriolatum Barker Krieger 1935. Rabh. Krypt. Flor. l3(1):227. P1. 9, Figs 0 1-6. This large cylindrical species is five to eleven times longer than.wide. The cell walls are brownish and 6. 119 ornamented by a series of longitudinal striae that are irregularly spirally arranged and which often anastomose or become replaced by linear series of punctations, es- pecially in the apical regions. The cell wall is punc- tate between the striae. A slight median constriction is present, and the apices are rounded or truncately rounded (rarely slightly dilated). Usually there are two chloroplasts in a semicell, each with a central pyrenoid. Measurements: L. 77-(250)-325u; W Distribution: . 15-(3o)-30u. SLP: Washtenaw, also MuSkegon (Transeau 1917); NLP, Cheboygan (N & A 1932); EUP, Schoolcraft; WUP, Gogebic (2), Houghton. Penium phymatosporum Nordst. Krieger 1935. Rabh. Krypt. Flor. 13(1): 237. Figs. 14-17. P1. 11, This small species is cylindrical and about two times longer than wide. The cell wall is colorless and ornamented with delicate striolations ( 11 per lOu). The lateral margins are often slightly constricted in the midregion and taper very slightly to the broadly rounded apices. Each semicell contains one chloroplast, each with a central pyrenoid. Measurements: L. 24-49u; W. ll-27u. Distribution: NLP, Cheboygan (N a A 1932); Isle Royale (Prescott 1941). 120 7. Penium polymorphum Perty Pl. 1, Fig. 5. Krieger 1935. Rabh. Krypt. Flor. l3(1):229. P1. 11, Figs 6 18-20 0 This small species is cylindrical or subcylindrical and two to two and one-half times longer than wide. The lateral margins usually have a slight median constriction and taper very slightly to the broadly, sometimes trun— cately rounded apices. The cell wall has very delicate but very closely arranged (about 18 per lOu) longitud- inal striolations. Each semicell has one chlorOplast with a central pyrenoid. Measurements: L. 34-(50)-(60)—79u; W. (l9.5)-(20.5)-36u. Distribution: SLP, Barry; EUP, Chippewa; WUP, Houghton, Baraga. New record for Michigan. 10. PLEUROTAENIUM Naegeli 1849 Cells, solitary or rarely in short filaments, usually relatively large, with length at least more than two times the width; generally cylindrical with lateral margins straight undulate, parallel or slightly convex and tapering toward apex; median constriction distinct but not deep; apex of semicell truncate, angles usually rounded; the poles either smooth or ornamented with a crown of granules or spines; semicell bases usually swollen and without plications. Cell wall smooth, Punctate, granulate or rarely of uneven thickness, which creates transverse rings of irregular ploygonal or quadrangular 121 areas. Chloroplasts extending the length of semicell, usually parietal straight or undulate bands with numerous pyrenoids, or more rarely an axial plate with a central row of pyrenoids. Zygospore spherical with smooth walls. Key to Species of Pleurotaenium 1. Cell wall smooth or punctate . . . . 2 1. Cell wall with numerous (12-15) transverse rings of irregularly polygonal or quadrangular areas formed by thin areas in the wall (1) P1. verrucosum 2. Pole of semicell smooth . . . . 3 2. Pole of semicell with spines, granules or warts . . . . . . 5 3. Chloroplast solitary in each semi- cell, an axial plate with longi- tudinal ridges . . . . . . . . . . (2) £1, minutum 3. Chloroplasts, many parietally placed narrow bands . . . . . . . A 4. Lateral margins undulate for more than half the length of semicell from the base .'. . (17) Pl, coronatum var. nodulosum 4. Lateral margin with one to three slight undulations above basal swelling of semi- cell, undulations never ex- tending to half the length of semicell . . . . . . . . . . (5) El. trabecula 5. Pole of semicell bearing short spines 0 O O 0 O O O O O O O O O O 6 5. Pole of semicell bearing granular warts o o o o o o o o o o o o o o 8 v and” H!) ell 122 6. Lateral walls bearing regu- larly Spaced whorls of mam- millate protuberances . . . (10) Pl, nodosum 6. Lateral walls otherwise 0 O O O 7 7- Lateral margins broadly undulate, undulations (not including basal swelling) usually four. Apex with more than three small granular spines . . . . . . . . . . . . . (11) P1. constrictum 7. Lateral margins straight except for basal swelling, apex bearing three short, sharp spines . . . . (12) Pl. tridentulum 8. Lateral margins with a distinct constriction Just below apex, cells usually Joined end to end in filaments . . . . . . (13) Pl. subcoronulatum var- Elsa 8. Lateral margins lacking a con- striction Just below apex, cells usually not Joined end to end in filaments . . O O O 9 9. 'Basal swelling very slight; lateral margins never undulate, slightly convex or straight, semicells tapering markedly towards apex . (14) Pl, truncatum Basal swelling distinct, lateral mar- gins straight or undulate or both straight and undulate in different portions, sometimes tapering grad— ually towards apex . 10. Width of semicell base 30-75u; robust form with thick cell walls; number of lateral mar- gin undulations above basal swelling variable, often reaching to middle or past middle of the semicell . . . (16) Pl, coronatum (inc. p.p. var. nodulosum) Width of semicell base 15-35u; slighter form with cell walls not thickened; often with single undulation above basal swelling, undulations very rarely reaching to middle of semicells . 10 10. . . . . . . . . . (18) Pl, Ehrenbergii 123 1. Pleurotaenium verrucosum (Bail.) Lund. Pl. 4, Fig. 5. Krieger 1937. Rabh. Krypt. Flor. l3(1);438. P1. 51, Fig. 3. This species is characterized by the twelve to fif- teen rings of irregular polygonal or quadrangular areas in the cell wall where the wall is thin. The presence of apical tubercles easily separates it from the some- what similar 21. trochiscum (not reported as yet for Michigan). Measurements: L. 200-(335)-516u; W. at base, 25-(32)- 45u; A. 16-(2l.5)-30u. Distribution: WUP, Gogebic. New record for Michigan. 2. Pleurotaenium minutum (Ralfs.) Delp. Krieger, 1937. Rabh. Krypt. Flor. 13(1):390. P1. 39, Figs. 2, 3. Characteristically, this species has either a very slight swelling or none at all at the base of the semi— cells. Apical tubercles are lacking and the chloroplast is an axial plate with longitudinal ridges. The writer follows Krieger (1937) by not separating fa. EElQE from the typical. Measurements: L. 60-(188)-(250)-270 at base; W: 7-(14)- (l6)-18u. Distribution: SLP, Washtenaw, Livingston, Berrien; NLP, Emmet, Presque Isle, Roscommon, also Cheboygan and Presque Isle (Taft 1939f, Penium.minutum) and Cheboygan (N & A 124 1932 Cosmarium docidioides); EUP, Chippewa, Schoolcraft; WUP, Gogebic, Houghton, Baraga. 3. var. elongatum (West and West) Cedergren Pl. 4, Fig. 6. Krieger, 1937. Rabh. Krypt. Flor. 13(1):393. P1. 39, Fig. 9. This variety is separated from the typical (8-12 times as long as wide) by the much elongated cell (30-40 times as long as wide). 21. trabecula var. elongatum resembles this variety but differs distinctly in the possession of pronounced swellings at the base of the semicells, and by having a smaller length-width ratio (19-28 times longer than wide). Measurements: L. 257-(352)-550u; w. 8-(16)-18u. Distribution: EUP, Alger. New record for Michigan. 4. var. gracile (Wille) Krieger Pl. 4, Fig. 4. Krieger, 1937. Rabh. Krypt. Flor. 13(1):394. P1. 39, Fig. 10. This variety is intermediate between the typical and var. elongatum in lengthewidth proportions (14-20 times as long as wide). Measurements: L. 110-(219)-220u; W. 6.5-(13)-14.5u. Distribution: EUP, Chippewa. New record for Michigan. 5. lgleurotaenium trabecula (Ehto Naeg. Krieger, 1937. Rabh. Krypt. Flor. 13(1):395. P1. 40, Figs. 1-4. Except for £1, minutum and El, coronatum var. nodu- losum, g1. trabecula is the only Michigan species that 125 lacks apical tubercles in the typical form. The former has either a very slight basal swelling or none. Semi- cells of P1. trabecula usually have a single distinct basal inflation (occasionally 1-3 undulations which do not extend to half the length of semicells) while 21, coro- natum var. nodulosum when lacking apical tubercles,has a distinct basal inflation and above it numerous undulations extending to half the length of the semicells. The writer follows Krieger (1937) in retaining fa. clavata within the typical. Measurements: L. 260-(384)-(402)-(408)-660u; W. at base (23)-24-(32)-40. Distribution: A very common and widespread species in Michigan. SLP, Calhoun, Ionia, Shiawassee, Washtenaw (2), Livingston, Oakland, Jackson, Berrien, Barry, Ingham, also Kalamazoo, Muskegon, Lapeer (N & A 1932), Ionia (Wade 1949), Wayne (Campbell 1886) and Macomb (Pieters 1894); NLP, Cheboygan, Emmet, Newaygo (N & A 1932, Welch 1938b) also Cheboygan (Pl. tribecula fa. glavata, N & A 1932); EUP, Chippewa, Alger, Mackinac, Delta, Schoolcraft, also Chippewa (N & A 1932), Schoolcraft (Transeau 1917); WUP, Gogebic (2), Iron, Menominee, also Baraga, Houghton, Ontanagon (N & A 1932); Isle Royale (Taylor 1935b, Pres- cott 1937). 6- var. hirsutum. (Bail.) Krieger Krieger 1937. Rabh. Krypt. Flor. 13(1):399- Pl- 41: Fig. 3. 126 This variety possesses short mucilaginous papillae on the surface of the cell wall. No other variety of £1, trabecula possesses this feature. Measurements: L. 245-500u; W. at base, 23-48u. Distribution: NLP, Emmet (N & A 1932). 7. var. maximum (Reinsch.) Roll. Krieger 1937. Rabh. Krypt. Flor. l3(1):400. P1. 40, Fig. 8. This variety is separated from the typical on the basis of its larger size. There are usually one to three slight undulations above the distinct basal swelling of the semicells. Measurements: L. 350-(830)-ll20u; W. at base, 48-(62)-65u. Distribution: SLP, Barry; NLP, Cheboygan (N & A 1932). 8. var. rectum (Delp.) West and West Krieger 1937. Rabh. Krypt. Flor. l3(1):402. P1. 41, Fig. 2. This variety is separated from the typical on the basis of its smaller size, primarily in the smaller width at the base of semicell. Measurements: L. 180-400u; W. at base, 14-23u. Distribution: SLP, Barry, also Muskegon (Transeau 1917, N & A 1932); NLP, Crawford, Emmet, also Cheboygan (Welch 1936b); EUP, Alger; WUP, Gogebic. 9- var. rectissimum West and West Pl. 4, Fig. 2. Krieger 1937. Rabh. Krypt. Flor. l3(1):401 P1. 41, Fig. 1. 127 This variety is separated from var. rectum by its greater length and the slightly greater length to width ratio (19-24 times longer than wide) than the typical (ll-18). It also has a much greater width at the base of the semicell. An additional characteristic of this var- iety is the presence of slightly dilated apices. Speci- mens from.Barry County agreed well with the measurements for this variety but lack the distinct dilated apices noted by West and West (1904). The writer therefore places these forms here questionably. Measurements: L. 400-(505)-628u; W. at base, 21-(24)-26u. Distribution: SLP, Barry. New record for Michigan. 10. Pleurotaenium nodosum (Bail.) Lund Krieger 1937. Rabh. Krypt. Flor. 13(1):436. P1. 47, Fig. 1. This species is easily distinguished by the trans- verse whorls of mammillate protuberances. Measurements: L. 250-(340)-520u; w. 40-(5l)-82u; A. 24-50u. Distribution: SLP, Berrien, also Muskegon (Transeau 1917); NLP, Emmet, also Cheboygan (Welch 1938b); Isle Royale, (Prescott 1937). ll. Pleurotaenium constrictum. (Bail.) Wood P1. 4, Fig. l. Krieger 1937. Rabh. Krypt. Flor. l3(1):42l. P1. 45, Fig. 8. This species characteristically has four broad undu- lations (not including basal swelling) of the lateral 128 margins in each semicell, the undulations extending through- out the greater length of the semicell. Four to five granular spines are visible at the apex in front view. Measurements: L. 415-(502)-580u; W. at base, 40-(44.7)- 50u. Distribution: SLP, Berrien; EUP, Chippewa. New record for Michigan. 12. ‘Pleurotaenium tridentulum (Wolle) West Krieger 1937. Rabh. Krypt. Flor. l3(1):408. P1. 43, Figs. 12-14. This species is easily separated from other Michigan species by the pronounced basal swelling, the distinct tapering of the lateral margins to the blunt rounded apex Which bears three or four spines (usually three seen in front view). Measurements: L. l60-(2l7)-320u; W. at base, l2-(l5)-l8u. Distribution: NLP, Cheboygan (N & A 1932); EUP, Chippewa. l3. lgleurotaenium subcoronulatum var. detum West and West ‘— P10 4, F180 30 Krieger 1937. Rabh. Krypt. Flor. l3(1):424. P1. 46, Fig. e. Distinctive features of this variety include the dilated truncate apex with a transverse ring of elliptic tubercles, the constriction of the lateral margins of the semicells at about one-tenth of the distance from the apex and the usually evident habit of remaining united end to end to form filaments. 129 Measurements: L. (372)-385-690u; W. at base, (23.5)- 24-45u; W. at apex, (23.5)-24—28u. Distribution: WUP, Gogebic, New record for Michigan. 14. Pleurotaenium truncatum (Breb.) Naeg. Krieger 1937. Rabh. Krypt. Flor. 13(1):430. P1. 49, Figs. 2, 3. One of the most distinct features that separates this species from others of the genus found in Michigan, is the short stout appearance (6-9 times as long as wide). In addition, the slight swelling at the base of the semi- cell and the convex lateral walls which taper sharply to the apex help distinguish this species. Measurements: L. 230—(372)-762u; W. at base, 40-(54)-85u; W. at apex, 24-42u. Distribution: SLP, Muskegon (Transeau 1917); EUP, School- craft. 15. var. Farquharsonii (Roy) West and West Krieger 1937. Rabh. Krypt. Flor. 13(1):433. P1. 49, Figs. 5, 6. This variety differs from the typical only in the presence of a slight but conspicuous concavity in the lateral margins Just below the apex. Measurements: L. 288-429u; W. at base, 44-62.4u. Distribution: Isle Royale (Prescott 1940). 16. ggeurotaenium coronatum (Bréb.) Rabh. Krieger 1937. Rabh. Krypt. Flor. 13(1):427. P1. 48, Figs. 1, 2. 130 This species is often mistaken for 21, Ehrenbergii from which it differs by having a more robust form, thicker cell walls and a usually greater width at the base of the semicells. The lateral undulations can also extend to the middle of the semicells whereas Pl, Ehren- bergii usually has only one to three undulations (some- times none) which do not extend to the midregion of the semicells. The tapering of the lateral margins to the apex is very slight in both Species. Measurements: L. 360-(521)-680u; W. 30-(51)-75u. Distribution: SLP, Muskegon (Transeau 1917), Kalamazoo (N a A 1932); NLP, Cheboygan (N a A 1932); EUP, School- craft; WUP, Marquette; Isle Royale (Prescott 1937). 17- var. nodulosum (Bréb.) West Krieger 1937. Rabh. Krypt. Flor. 13(1):429. P1. 48, Fig. 4. This variety is separated from the typical by a com- bination of characteristics. The tapering of the semi- cells to the apex is much sharper than in the typical. The number and extent of the undulations of the lateral margins are variable (often extending through almost the entire length of the semicell); the apical granules may either be completely lacking, strongly reduced, or pre- sent as normal granules. Measurements: L. 335-(460)-(516)-670u; W- at base, 36- (43)-(53.7)-65u; N. at apex, 23-(32.5)-44u. 131 Distribution: SLP, Barry, Washtenaw, also Wayne (Camp- bell 1886, gl, crenulatum); NLP, Cheboygan (N & A 1932, ‘21. crenulatum); WUP, Houghton,_also Marquette (Pres. a Mag. 1935, El. nodulosum); Isle Royale (Prescott 1937). I 18. Pleurotaenium.Ehrenbergii (Breb.) De Bary Krieger 1937. Rabh. Krypt. Flor. l3(1):410. P1. 42, Figs. 4-8. This species is very variable in size, in propor- tions of length to width, and in the degree of tapering of the lateral margins to the apex. The features that distinguish it from P1. coronatum and £1, coronatum var. nodulosum have been discussed previously. Some of the general characteristics are: fifteen to twenty times as long as wide, distinct basal swelling with sometimes a single undulation on the lateral margin above the basal swelling, middle lateral margins parallel, usually slightly tapering to the apex. Measurements: L. 220-(349)-700u; W. at base, 15-(30.4)- 35u. Distribution: Very widely distributed in the writer's collections. SLP, Calhoun, Barry (3), Ingham, Jackson; NLP, Roscommon, Crawford, also Cheboygan (N & A 1932, Neal 1948); EUP, Schoolcraft, Delta; WUP, Houghton, Gogebic (3), also Isle Royale (Prescott 1940). 19. var. elongatum (W. West) West and West Krieger 1937. Rabh. Krypt. Flor. 13(1):414. P1. 43, Fig. 3. 132 This variety is twenty to twenty—five times longer than broad whereas the typical is fifteen to twenty times longer than broad. Measurements: L. 390-575u; W. at base, 18-26u. Distribution: SLP, Oakland (Transeau 1917); NLP, Crawford. 11. DOCIDIUM Breb. 1844 (Emend. Lundell 1871) Cells straight, solitary, always longer than broad, cy- lindrical, with a slight median constriction; semicells with lateral margin undulate or straight, and with apices truncate and smooth; base of semicells always inflated and with longi- tudinal plications. Cell wall smooth, punctate or finely striated. Chloroplast axial with irregular longitudinal ridges, single in each semicell; pyrenoids (6-8) in a linear series. Zygospore unknown. Key to Species of Docidium 1. Lateral margins undulate through- out the entire length of the semicell . . . . . . . . . . . . . (2) D, undulatum 1- Lateral margins with a single undu— lation at the base of the semi- cell . . . . . . . . . . . . . . (1) D, baculum 1» Epcidium baculum Bréb. Krieger, 1937. Rabh. Krypt. Flor. 13(1):379. P1. 38, The longitudinal plications and the single swelling at the base of each semicell clearly differentiates this CN fl 1.. 133 species. The width of the cell is always below 20u. Measurements: L. 150-(185)—(267)—430u; W. 9.5-(13)-20u; A. 5-8-12u. Distribution: SLP, Barry; NLP, Cheboygan (Taft 1939); EUP, Delta. 2. Docidium.undulatum Bailey Krieger, 1937. Rabh. Krypt. Flor. 13(1):380. P1. 38, Figs. 9-12. The undulate margins separate this species easily from.any other reported from Michigan. Measurements: L. 165-(265)-300u; W. l2-(13)-l7u; A a 11"(15) -1541 0 Distribution: NLP, Cheboygan (Taft 1939); EUP, Chippewa. 12. TRIPLOCERAS Bailey 1850 Cells large, straight, always much longer than wide, with a slight but well defined median constriction. Semicells cy- lindrical with lateral margins slightly tapered to apices. Apices flattened with two or three long, upwardly turned ob- liquely placed lobes or projections with truncate ends that bear two to three short, sharp spines; sometimes with one or two secondary protuberances each with one or two spines, lo- cated between two apical processes. Lateral margins strongly undulate with the undulations produced by transverse whorls of protuberances, each protuberance bearing simple spines Or \ emarginate two to nine parted verrucae. Chloroplast axial, ~ ~ 04.. FPV AMA! 134 one in each semicell, with longitudinal plates extending from median axis to the lateral walls, pyrenoids in an axial row. Zygospores unknown. Key to Species of Triploceras 1. Lateral margins bearing whorls of protuberances which have in the midregion of the semicell, em- arginate verrucae . . . . . . . . (l) T, verticillatum 1. Lateral margins bearing whorls of protuberances all of which possess simple spines . . . . . . . . . . (2) T, gracile 1. Triploceras verticillatum Bailey Pl. 5, Fig. 1 Krieger, 1937. Rabh. Krypt. Flor. 13(1):446. P1. 52, Figs. 19-22. This species has the semicells bearing transverse whorls of elevations or protuberances with two types of proJections. The upper whorls have protuberances with short, upwardly directed spines, whereas the median and 3 lower whorls have the protuberances with two-to-nine- ‘ parted proJections. Measurements: L. (300)-380-506u; W. csp. 30-(50)-50u. Distributions: SLP, Berrien; NLP, Emmet. New record for‘Michigan. 2. Triploceras gracile Bailey Krieger, 1937. Rabh. Krypt. Flor. 13(1):442. P1. 52, 4 Figs. 1-7. This species with apical spines and the transverse \ 'whorls of protuberances with simple spines cannot be confused with any other species. we! '4 '8." PH” 01‘ u. 135 Measurements: L. 206-(398)—668u; w. csp. 21-(32)-53u; A. 24-40u. Distribution: NLP, Emmet (N & A 1932); EUP, Chippewa. 13. TETMEMORUS Ralfs. 1844 Cells straight, always longer than wide, median constri- ction relatively shallow with an open sinus. Semicells sub- fusiform, cylindrical, lateral margins usually tapering to apices which have a distinct deep vertical incision. Cell wall smooth, punctate, scrobiculate or with longitudinal rows of elongated, flattened thickenings. ChlorOplast, axial, single in each semicell, with longitudinal radiating plates that are entire or cleft at their margins. Pyrenoids fairly numerous and linear along the axis. Zygospores, spherical to rectangular (sometimes with arms) with walls that are smooth. 4 Key to Species of Tetmemorus k 1. Cell walls with longitudinal rows ‘~ of flattened wall thickenings , (considered punctulations or { scrobiculations by West and West = 1904, and many others) . . . . . (1) T: Brebissonii } 1. 4 Cell walls with irregularly arranged punctations or scrobiculations . 2. Semicells very slightly tapered to the apices; apices only slightly less in diameter than at their bases . . . . . (3) 2: 1aevis 136 2. Semicells gradually and reg- ularly tapered from the base to apex; apices distinctly less in diameter than at their bases . . . . . . . . . (5) T, granulatus 1. Tetmemorus Brebissonii (Menegh.) Ralfs. Krieger, 1937. Rabh. Krypt. Flor. l3(1):452. P1. 54, Figs. 1-5. This species is distinguished by the longitudinal rows of elongate, flattened wall thickenings (scrobicula- tions or punctulations according to many authors) on the cell walls. Measurements: L. lOO-(ll7)-264u; W. 19-(23.5)-39u; I. 21-(2l.3)-32u. Distribution: SLP, Barry, Livingston; NLP, Presque Isle (Taft 1939); WUP, Gogebic (2). 2. var. mTpgg. De Bary Krieger, 1937. Rabh. Krypt. Flor. 13(1):454. P1. 54, Figs. 6, 7. This variety is separated from the typical by smaller size. The semicells are scarcely tapered near the apices, and the lateral margins are slightly concave in the middle of the semicells. The Roscommon County specimens were intermediate between the typical and variety. Measurements: L. 57-(98)-100u; W. 15-21-(2l.8)u; I. 12-15-(17)u. Distribution: SLP, Barry, Livingston, also Calhoun (Pres. & Mag., 1935, fa. minutus); NLP, Roscommon, also Cheboygan (N & A 1932); EUP, Chippewa. 137 3. Tetmemorus laevis (Kfuetz) Ralfs. Krieger, 1937. Rabh. Krypt. Flor. l3(1):455. P1. 54, Figs. 9-12. This species has the semicells very slightly tapered to the apices. The width of the apices is only slightly less than at the median constriction. The cell wall has minute irregularly arranged punctations. Measurements: L. 60-(93)-145u; W. 17-(22)-30u; I. 16-(19)-27u. Distribution: NLP, Roscommon, also Cheboygan (N & A 1932; Welch 1938a); EUP, Chippewa, Schoolcraft (2); WUP, Hough- ton, Gogebic; Isle Royale (Prescott, 1937, 1941). 4. var. minutus (De Bary) Krieger Krieger, 1937. Rabh. Krypt. Flor. l3(1):457. P1. 55, Figs. 8, 9. This variety differs from the typical in the smaller size. The lateral margins of the semicells are slightly convex. Measurements: L. 42-(58)-65u; W. 12-(19)e24u. Distribution: SLP, Livingston; NLP, Cheboygan (N a A 1932, T, minutus). 5- .Tgtmemorus granulatus (Bréb.) Ralfs. Krieger, 1937. Rabh. Krypt. Flor. 13(1):458. P1. 55, Figs. 1-5. This species has an irregularly scrobiculate cell wall. The lateral margins are gradually and regularly 138 attenuated toward the apices. Measurements: L. 80-(183)-260u; W. 20-(32)-50u; I. 25-(28)-37u. Distribution: SLP, Livingston; NLP, Crawford (N a A 1932); EUP, Chippewa (N a A 1932); Isle Royale (Pres- cott 1941). 6. var. attenuatus West Krieger, 1937. Rabh. Krypt. Flor. l3(1):459. P1. 55, Fig. 6. This variety differs from the typical by the lat- eral margins being slightly and abruptly attenuated a slight distance below the apices. The lateral margins, however, are gradually tapering from the base of the semicells to the apices. Measurements: L. l60-260u; W. 30-48u. Distribution: NLP, Cheboygan (Taft 1939). 14. EUASTRUM Ehrenb. 1832, emend. Ralfs. 1844 Cells of variable size, usually longer than wide, deeply constricted, sinus usually linear; the semicells generally truncate-pyramidate, the apex with a vertical median incision 0f variable length or the apex slightly emarginate or broadly Petuse. The cell wall smooth, punctate or scrobiculate with f'aclal swellings variously disposed, often ornamented with var- ious patterns of granules, papillae; lateral margins often 139 bearing spines. Cells in vertical view generally elliptic with rounded poles and lateral swellings. Chloroplasts in large species axial with lobes (to each cell face) that end in massive parietal plates; in small species, the chloroplasts axial with simple lobes; rarely two chloroplasts in each semi— cell. Pyrenoids one to many. Zygospore spherical to globose; wall smooth, mammillate or with spines. Key to Species of Euastrum l. Apical incision deep or moderately deep, linear or narrowly v-shaped. 15 1. Apical incision shallow, apex ap- pearing slightly emarginate, or apical incision lacking, apex either entire or broadly retuse .. 2 2. Apex bearing a crown of gran- ules . . . . . . . . . . . . (28) E, attenuatum 2. Apex otherwise . . . . . . . 3. Cells over 40u long . . . . . . . 3. Cells under 40u long . . . . . . . . 6 4. Cell wall smooth punctate, scrobiculate . . . . . . (23) E, pectinatum 4. Cell wall granulate . . . . . . 5 5. Cell more than 70u long and more than 50u wide . . . . . . . . . . (61) E, verrucosum 5. Cell less than 70u long and less than 50u wide . . . . . . . . . . (60) E, gemmatum 6. A granule present above the isthmus near the base of the semicell . . . . . . . . . . 7 7. 7. 11. 11. 140 6. No granules present as above . 8 Central face of semicell with a pap- illate protrusion . . . . . . . . (39) E, bipapillatum Central face of semicell with a muc- illage pore . . . . . . . . . . . (33) E; validum 8. Semicell with a single large swelling in the central fac- ial area and with four small wart-like swellings distri- buted on the basal and apical lobes . . . . . . . . . . . . (32) E, crassangulatum 8. Cell otherwise . . . . . . . . 9 Cell about 1 1/4 times longer than wide. Lateral and apical lobes with spines; two short spines at apex, one on either side of the emargination; central face of semicell with a papillate protru- sion . . . . . . . . . . . . . . . (40) E, sibiricum Cell not having the above combina- tion of characters . . . . . . . . 10 10. One or more lateral undulations between apical and basal lobes . . . . . . . . . . . . 12 10. No lateral undulations between apical and basal lobes . . . 11 Apical angles usually rounded or ob- tuse, cell 1 1/2 times longer than Wide . . . . . . . . . . . . . . . (30) E, sublobatum Apical angles usually acuminate, cus- pidate or sharp angled, cells 1 1/5-1 1/4 times longer than wide (35) E, binale l2. Lateral margins of semicell with a single undulation between the apical and basal angles (lobes) . . . . . . . . . . . 13 12. Lateral margins of semicell with two undulations between the apical and basal angles 1 bes . . . . . . . . . . . (37) E, binale ( o ) var. Gutwinskli 13. 13. 15. 15. 17. 17. 19. 19. 141 Cell 1 3/4-2 times longer than wide . . . . . . . . . . . . . . . (42) E. crassicolle var. Bicrenatum Cell less than 1 3/4 times longer than wide . . . . . . . . . . . . l4 14. Cells bearing granules, some- times greatly reduced, either on lobes or on central facial protuberances of semicell or on both . . . . . . . . . . . (41) E, dubium 14. Cells not bearing granules, central facial region of semicell wall thickened . . . (38) E, insulare Spines located upon some part of semicell margin . . . . . . . . . 16 Spines not located upon some part of semicell margin . . . . . . . . . 31 16. Upper lateral lobe present, either slightly or well ex- serted . . . . . . . . . . . 21 16. Upper lateral lobe not present . 17 Upper margins of apical lobes con- verging to mid-region of semicell. (49) E, elegans Upper margin of apical lobes hori- zontally truncate or nearly so . . 18 18. Cell length more than 34u . . . 19 18. Cell length less than 34u . . . 2O Lateral margin Just above basal angle, bearing a single long hori- zontally directed spine . . . . . (50) E, divaricatum Lateral mar in above basal angle otherwiseg . . . . . . . . . . . . (54) E, Ciastonii 20. Central area of face with a f five circular gran- :128 o. . . . . . . . . . . . (46) E, trigibberum 21. 21. 23. 23. 25. 27. 27. 142 20. Central area of the face with 3-4 oblong granules disposed in an irregularly triangular or quadrangular pattern; usu— ally two additional semi-cir- cular granules located between the central group and the isthmus . . . . . . . . . . . (44) E, denticulatum Upper margins of apical lobe con- verging toward the apex . . . . . (51) E, bidentatum Upper margins of apical lobe hori- zontally or almost horizontally truncate . . . . . . . . . . . . . 22 22. Lateral margins bearing a hori- zontal protrusion or proJect- ion a short distance below the apical spines . . . . . . 23 22. Lateral margins smooth Just be- low the apical spines . . . . 25 Length of cell more than 50u (rarely under 50u) . . . . . . . . (55)E _. evolutum Length of cell less than 50u . . . . 24 24. Width of cell more than 25u . . (46) E, trigibberum 24. Width of cell less than 25u . . (48) E. Turneri Lateral margin a short distance above basal angle bearing a single long horizontally directed spine . . . (50) E, divaricatum Lateral margin above basal angle otherwise . . . . . . . . . . . . 26 26. Central area of the semicell wall with a single thickened protrusion . . . . . . . . 27 26. Central area of semicell wall with granules . . . . . . . . 28 Apical spines divergent . . . . . . (59) E. oculatum var. tonsum Apical spines horizontal . . . . . . (52) E, lapponicum fa. 29. 29. 31. 31. 33. 33. 35. 35. 143 28. A pair of mucilage pores lo- cated above facial granu- lation . . . . . . . . . . . 3O 28. A pair of mucilage pores not present above facial granu- lation . . . . . . . . . . . 29 Length of cell 38.5-57u . . . . . . (54) E, Ciastonii Length of cell 25-38u . . . . . . . (41) E, dubium 30. Length of call over 40u, width over 28u, semicell width at lateral lobes usually greater than at basal lobe . . . . . (53) E. abruptum 30. Length of cell under 4lu, width under 30u, semicell width at lateral lobes never greater than at basal lobe . . . . . (47) E, pulchellum Upper lateral lobes well developed, exserted and distinct . . . . . . 32 Upper lateral lobes either not pre- sent or if present, forming mar- ginal undulations . . . . . . ... 38 32- Face of semicell with a pattern of at leaSt 11 swellings, each with a mucilage pore . . . . (9) E, Jenneri 32. Cell wall otherwise . . . . . . 33 Polar lobe separated from lateral lobes by a narrow sinus . . . . . 34 Polar lobe separated from lateral lobes by a widely Open sinus . . . 36 34. Lateral lobes truncate . . . . (19) E, oblongum 34. Lateral lobes bluntly rounded or bluntly pointed . . . . . 35 Cells about 1.6-1.7 times longer than wide, lateral lobes in side view entire . . . . . . . . . . . (13) E, ventricosum Cells about 1.75-2 times longer than wide, lateral lobes in side view two parted . . . . . . . . . . . . (10) E, crassum 37- 37. 39. 39. 144 36. Basal swellings thickened at margin, those lateral in pos- ition rectangular and obliquely placed; sinus between lateral and basal lobes often very broad and shallow . . . . . . (18) E, Eumerosgm 36. Basal swelling sometimes thick- ened at margin, none rectang- ular or obliquely placed; sinus between the lateral and basal lobes always deep . . . 37 Apex and polar lobes broadly rounded; upper lateral lobe exserted slight- 1y; sinus between polar and later- a1 lobes broadly open and with a broadly rounded apex . . . . . . . (16) E, affine Apex more anvil-shaped, angles of polar lobes bluntly pointed; upper lateral lobes exserted strongly; sinus between polar lobe and lat- eral lobe open and with a sharply rounded apex . . . . . . . . (17) E, pinnatum 38. Semicell wall containing at least five facial swellings, each with a mucilage pore (6) E, ETnuosum 38. Semicell wall with a variable number of facial swellings, never a mucilage pore with- in each swelling . . . . . 39 Entire length of lateral margins a series of undulations . . . . . . (43) E, incrassatum Lateral margins not undulate or un- dulate only in small portion . 40 40. Lateral margins without undula— tions between basal lobes and 41 apical lobe . . . . . . . 40. Lateral margins with some undu- lations (sometimes very slight) between basal lobes and api- cal 10be 0 O O O O O O O 0 I an 41. 41. 43. 43. 45. 45. 47. 47. 145 Apex capitate . . . . . . . . 42 Apex not capitate . . . . . . . 44 42. Both apical and basal lobes broadly rounded . . . . . . . (21) E, intermedium fa. 42. Both apical and basal lobes 43 bluntly pointed . . . . . Semicell wall with two basal and median submammillate downward pro- Jecting swellings . . . . . . . . (20) E, insigne Semicell wall with two somewhat broadly rounded swellings . . . . (22) E. Entermedium var. :pngicolle 44. Cell length less than 58u, less than twice the width . . . . (5) E, pingue 44. Cell length more than 58u, at least twice the width . . . . (2) E, ansatum Apex and apical lobes broadly rounded 46 Apex anvil-shaped, apical lobes bluntly pointed . . . . . . . . . (20) E, insigne 46. A single slight undulation pre— sent on the lateral margin less than halfway above the basal angle . . . . . . . . . 47 46. A single slight undulation pre— sent on the lateral margin about half-way between the basal and apical angles . 48 A central mucilage pore present in the face of the semicell . . . . . (3) E. ansatum fa. SCO (l) E. cuneatum_var. No mucilage pore present . . . . __ _1 subansatgm_fa. 48. Cell 1.5 times longer than wide, three mucilage pores in cen- tral area of semicell . . . . (14) E, ampullaceum 48. Cell 1J6-2 times longer than wide, a single mucilage pore or none in central region of 49 semicell . . . . . . . . . . 146 49. A mucilage pore present in central region of semicell . . . . . . . . (15) E, didelta 49- A mucilage pore absent in central region of semicell . . . . . . . . (4) E, ansatum var. submaximum 1. Euastrum cuneatum var. subansatum Kossink. fa. Pl. 5, Fig. 2. Krieger, 1937. Rabh. Krypt. Flor. 13(1):481. P1. 57, Fig. 1. This variety differs from the typical in the smaller size and the greater develOpment of the lateral margin A single specimen from Marquette County In addition, this undulation. agrees with the description closely. specimen had three very slight facial swellings, one basal and two above. Krieger (1937) does not mention facial swellings nor does his illustration (taken from original author) indicate their presence. There are three basal facial swellings in the typical and from 1-5 in other varieties. The Michigan form should be compared with E. ansatum var._suprapositum Nordst. which has a distinct mucilage pore above the two middle facial swellings. Measurements: 72-(86)-BQU; W- 37-(43)-43u; I- 10-(10-7)- l4u; A. 18-20u. Distribution: WUP, Marquette. Krieger (1937) reports that this variety has been reported New record for Michigan. only from the Arctic (Greenland, etc.). , 2- Euastrum ansatum Ralfs. Krieger, 1937. Rabh. Krypt. Flor. 13(1):484. P1. 58, Figs. 1-30 147 The triangular shape of the semicells, the truncate polar lobes with the subparallel lateral margins diverg- ing to a broad base, help distinguish this Species. The lateral margins may be slightly undulate above the basal region. The semicell wall has five facial swellings, three in the basal region, two above, arranged trans- versely. Measurements: L. 61-(105)-110u; w. 32-(49)-51u; I. 8- (13)-15u; A. 16—24u. Distribution: SLP, Barry, also Muskegon (Transeau 1917); NLP, Emmet; Isle Royale (Prescott 1937). 3- fa. Scottii fa. nov. Pl. 5, Fig. 3. Prescott and Scott, 1945. Am. Mid. Nat. 34:233. P1. 3, Fig. 2. (E, ansatum fa.). This form differs from the typical in the presence of only a single basal swelling of the semicell wall in the presence of a central mucilage pore. The Michigan specimens show a slight undulation of the lateral margin above the basal angle. Measurements: L. (105)-llOu; W. 33-(47)u; I. (l3)u. Distribution: EUP, Schoolcraft. New record for Michigan. 4. var. submaximum Borge P1. 5, Fig. 4. Krieger, 1937. Rabh. Krypt. Flor. l3(1):491. P1. 59, Figs. 13-6. This variety is separated from the typical by the slight undulation of the lateral margin about halfaway . I‘l— 148 between the basal and apical angles. In side view, there is only a single slight middle swelling and in vertical view, the facial swelling appears as two slightly pro- Jected undulations on the margin. Specimens from School- craft County fit this variety, except for the slightly deeper apices. The writer believes that E, obesum var. crassum Prescott and Scott (1942) should also be placed here although this variety is somewhat broader in side view. Measurements: L. (97)-108-ll7u; W. (53.7)-64u; I. 13- 13.5-16u. Distribution: EUP, Schoolcraft. New record for Michigan. 5. Euastrum pingue Elfw,P1. 5, Fig. 5. Krieger, 1937. Rabh. Krypt. Flor. l3(1):497. P1. 61, Figs. 19‘22. This small species is less than two times longer than broad, has trapeziform semicells, the basal lobes broadly rounded, and the apical lobes divided by open shallow median incision. The cell wall is scrobiculate, the markings larger at the lobes and at the center of the semicells. In addition, there is a large excentric mucilage pore and a basal papilla at the isthmial re- gion in each semicell. Measurements: L. 52-(58)-58u; W. 35-(41)-45u; I. lO-(10.7)-12u; A. 18-20u. Distribution: NLP, Cheboygan. New record for Michigan. 149 6. Euastrum sinuosum Lenorm. Krieger, 1937. Rabh. Krypt. Flor. l3(1):499. P1. 62, Figs. 9’11. The five facial swellings (three basal and two cen- tral) each with a mucilage pore are the distinguishing characteristics of this species. The lateral marginal undulation is variable. Measurements: L. 52-87u; W. 28-50u; I. 8-15u; A. 19-21u. Distribution: NLP, Cheboygan (N a A 1932, Welch 1938a). 7. var. reductum West and West Rabh. Krypt. Flor. 13(1):5o2. P1. 62, Krieger, 1937. Fig. 25. This variety is ssparated from the typical by the somewhat smaller size, the non-dilated poles, and the reduced lateral.hergin undulation. In vertical view, the facial swellings are less pronounced. L. 46-(60)-74; W. 24—(43)-44u; I. 8-15u. NLP, Crawford (Taft 1939); WUP, Gogebic.) Pl. 6, Fig. 5. Measurements: Distribution: 8. var. aboense (Elfv.) Cedr. Krieger, 1937. Rabh. Krypt. Flor. 13(1):500. P1. 62, This variety has five facial swellings (three up- Per, two lower) each with a mucilage pore upon each semicell. In addition, there are two pores placed be- tween the upper facial swellings and each lateral basal swelling making a total of eleven pore in semicell wall. 150 In the Michigan specimens the facial swellings and the apical and basal lobes are much more conspicuously punc- tate than the rest of the semicell wall. This variety should be compared with E, sinuosum var. subJenneri West and West which has eleven facial swellings, each with a pore, and a more exserted polar lobe. Measurements: L. 52-(68)-70u; W. 30-(40.4)-42u; I. 10-13u; A. 16-l8u. Distribution: EUP, Schoolcraft. New record for Michigan. 9. Euastrum Jenneri Arch. Krieger, 1937. Rabh. Krypt. Flor. l3(1):505. P1. 63, Fig. 8. The rounded subrectangular shape of the lower part of the semicell and the presence of eleven facial swell- ings each with a mucilage pore, distinguishes this species. Measurements: L. 72—76u; W. 45-48u; I. l5u. Distribution: NLP, Cheboygan (N a A 1932)- 10. Euastrum crassum (Breb.) Kuetz. Krieger, 1937. Rabh. Krypt. Flor. 13(1):510. P1. 66, Fig. 1. This large species (about 1 3/4-2 times longer than broad) has capitate apices, lateral lobes usually sep- arated from apical lobes by deep or slightly linear in- cision and a strongly punctate cell wall. The cell wall has three basal swellings (rarely two additional middle swellings) in a transverse plane. This organism is 151 closely related to E, ventricosum but differs from it in the possession of a larger lengthawidth ratio and in the lateral lobes being two parted when seen in lateral view. Measurements: L. l25-(126)-275u; W. 63-(71)-118u; I. 18-(21.3)-35u; A. 42-65u. Distribution: SLP, Muskegon (Transeau 1917); NLP, Emmet, also Emmet (Transeau 1917). 11. var. scrobiculatum Lund. Krieger, 1937. Rabh. Krypt. Flor. 13(1):512. P1. 65, Figs. 2—5. This variety is distinguished from the typical pri- marily by the presence of one to four mucilage pores ar- ranged in various patterns in the central region of semicell wall. Measurements: L. l34-(144)-170u; W. 65-(75)-88u; I. 18-(21.8)-26u. Distribution: SLP, Livingston, also Calhoun (Pres. & Mag. 1935); NLP, Emmet, Roscommon; WUP, Gogebic; Isle Royale (Prescott 1940). 12. var. michiganense Prescott Prescott and Magnotta, 1935. Pap. Mich. Acad. Sci, Arts and Letters. 20:165. Pl. 126, Fig. 1, 2. This variety is separated from the typical by the presence of only a single basal swelling of the semicell wall. Measurements: L. 156-159.5u; W. 87-89.7u; I. 23—25.5u. Distribution: WUP, Marquette (Pres. & Mag. 1935). 152 13. Euastrum ventricosum Lund. Krieger, 1937. Rabh. Krypt. Flor. l3(1):513. P1. 64, Figs. 1-3; P1. 65, Fig. 1. This species is similar to E, crassum from.which it differs in possession of a smaller length-breadth ratio and the entire lateral lobes in lateral view. Measurements: L. 80-l73u; W. 49-103u; I. l4-28u; A. 35-43u. Distribution: NLP, Cheboygan (Taft 1939); Isle Royale (Prescott 1940). 14. Euastrum ampullaceum Ralfs. Krieger, 1937. Rabh. Krypt. Flor. l3(1):515. P1. 64, Figs. 6-8. The somewhat cuneate polar lobe with rounded angles and the three mucilage pores in the central region of the semicell wall easily distinguish this species. Measurements: L. 66-124u; W. 45-75u; I. lO-20u; A. 22-42u. Distribution: NLP, Cheboygan (N & A 1932). 15. Euastrum didelta Ralfs. Krieger, 1937. Rabh. Krypt. Flor. l3(1):517. P1. 66, Fis- 6; P1. 67, Figs. 1-3. This very variable species has trapeziform-pyramidate semicells with five facial swellings in semicell wall. Three are placed transversely in the basal region, and two transversely above. Between the latter, a mucilage pore is often located. The lateral margins usually have a broad undulation about halfaway between the basal and apical angles. The apex has a deep linear incision, and 153 the apical lobes are usually broadly rounded. Some speCi- mens from Barry and Marquette Counties generally resembled a new forma illustrated by Irenee—Marie (1938). The two upper facial swellings were much more pronounced than the basal swellings. The middle basal swelling was somewhat reduced in size but very distinct. According to Irenee- Marie (1938), this form has granular cell walls, while the Michigan forms were definitely scrobiculate. They agree more Closely with the organism illustrated by Hirn (1903) as E, didelta fa. scrobiculata Nordst. which is considered by Krieger to be synonomous with the typical. Measurements: L. (98)~102-(111)-(l24)-150u; W. 52—(53)- (64)-(66)~82u; I. l2-(l3)-(17.2)-27u; A. 20-24u. Distribution: SLP, Barry, Calhoun, Berrien; NLP, Emmet, also Cheboygan (N a A 1932, Welch 1938a) and Emmet (Tran- seau 1917); EUP, Schoolcraft, also Chippewa (N a A 1932); WUB Gogebic, Marquette; Isle Royale (Prescott 1937). 16. Euastrum affine .Ralfs. Krieger, 1937. Rabh. Krypt. Flor. l3(1):524. P1. 68, Figs. 2-4. This species is very Close to E;_pinnatum from which it differs in the longer but more shallow sinus between the lateral and basal lobes. The lateral lobes are thus. less exserted horizontally. Measurements: L. 92-(115)-(l29)-l40u; W. 50-(64)-(68)-81u; I. l2-(15)-(17)—24u; A. 24-31u. 154 Distribution: SLP, Calhoun, Barry, Livingston; NLP, Ros- common, also Cheboygan (N & A 1932, Welch, 1938a); EUP, Schoolcraft, also Chippewa (N & A 1932); WUP, Gogebic; Isle Royale (Prescott 1937, 1940). 17. Euastrum pinnatum Ralfs. Krieger, 1937. Rabh. Krypt. Flor. l3(1):522. P1. 68, Figs. 5—7. This species is closely related to E, affine and E, humerosum. It is separated from the former by the more exserted lateral and apical lobes, and from the latter by the more horizontal lateral lobes; the often more deep incision between the lateral lobes and basal lobes and the facial swellings of semicell wall not being thickened as greatly at the margins and not placed obliquely. Measurements: L. 110-156u; W. 58-80u; I. l7-30u; A. 26-42u. Distribution: NLP, Emmet, also Cheboygan (N a A 1932); EUP, Mackinac (Transeau 1917); WUP, Gogebic; Isle Royale (Prescott 1937). 18. Epastrum humerosum. Ralfs. Krieger, 1937. Rabh. Krypt. Flor. l3(1):524. P1. 69, Figs. 4-6. This species is very variable in respect to the depth of interlobular incision, the shape of the polar lobe and the amount of proJection of the upper lateral lobe. It can be distinguished from.E, pinnatum.and E, affine by the more shallow and broader sinuses between 155 the lateral and basal lobes and the more pronounced basal angles that are thickened at their margins and obliquely placed. A single specimen from Roscommon County appears somewhat intermediate between E, humerosum and E, pinnatum. Measurements: L. 104-(148)-l60u; W. 60-(74)-90u; I. 14-(19.5)-29u; A. 27-42u. Distribution: SLP, Barry; NLP, Roscommon, Crawford, Emmet, also Cheboygan (N & A 1932, Welch 1938a); EUP, Chippewa. 19. Euastrum oblongum (Grev.) Ralfs. Krieger, 1937. Rabh. Krypt. Flor. l3(1):526. P1. 70, Figs. 3-6. This species can be distinguished readily by the oblique truncate shape of the lateral lobes. The var- iety cephalophorum.West, is included here. Measurements: L. lO7-(161)-(l64)-205u; W. 48-(68)-(72)- lO7u; I. 13-(21.5)-31u; A. 34-53u. Distribution: SLP, Washtenaw, Barry; NLP, Crawford, Ros- common, also Cheboygan (N & A 1932, also as var. cephalo- phorum); EUP, Schoolcraft, alger; WUP, Houghton; Isle Royale (Prescott 1937). 20. Euastrum insigne Mass. Krieger, 1937. Rabh. Krypt. Flor. l3(1):529. P1. 71, Figs. 1-30 The elongate triangular shape of the semicells, the submammillate basal lobes, the capitate polar lobe and 156 the two sub-mammillate downward proJecting swellings of the semicell wall partly characterize this species. Some specimens from Chippewa County were intermediate between the typical and E, insigne var. lobulatum Prescott and Scott. Measurements: L. 80-(100)-l44u; W. 43-(56)-76u; I. (10.5)- 11-20u; A. 22-42u. Distribution: NLP, Cheboygan (N & A 1932); EUP, Chippewa(2). 21. Euastrum intermedium Cleve. fa. P1. 6, Fig. 2. Krieger, 1937. Rabh. Krypt. Flor. l3(1):532. P1. 71, Figs. 6-8. Characteristically, this species has trilobed semi- cell, the basal lobes obtusely conical or broadly rounded, and the polar lobe somewhat anvil-shaped with acutely rounded angles. Two facial swellings of the semicell wall arranged transversely between the basal lobes and two small facial swellings upon the polar lobe are also typical. Krieger (1937) states that the cell wall is porous whereas West and West (1905) state that it is smooth. Specimens from Schoolcraft County have the apical poles less capitate with the angles more broadly rounded; and lacked the two facial swellings. The cell wall punc— tation was more pronounced upon the lobes and upon the facial swellings, the latter placed much higher up on the semicell than in the typical. It should be compared With E, intermedium var. verrucosum Krieger, and E, inter- 4'6 22. 23. 24. 157 medium var. scrobiculatum Schmidle (not found in Michigan). Measurements: L. 54-(76.6)-80u; W. 31-(40.4)-45u; I. 8-(10.6)-12u. Distribution: EUP, Schoolcraft. New record for Michigan. var. longicolle Borge Pl. 6, Fig. l. Krieger, 1937. Rabh. Krypt. Flor. l3(1):533. P1. 71, Figs. 9-11. The basal lobes of this variety are not as broad and are more pointed than the typical. The polar lobe is more elongate, and the apical lobes are rather sharply pointed. Measurements: L. 60-(70.5)-79u; W. 38.5-(43)-43u; I. 7-10u; A. 18.5-20u. Distribution: WUP, Gogebic. New record for Michigan. Euastrum pgctinatum Bréb. Krieger, 1937. Rabh. Krypt. Flor. l3(1):537. P1. 72, Figs. 4-7. Some of the more prominent characteristics of this species are the convex truncate apex that is slightly retuse in the middle, the subquadrate basal lobes, the three facial swellings across the widest part of the semicell, and the two facial swellings on the polar lobe. Measurements: L. 48-84u; W. 30-49u; I. 8-16u; A. 32-35u. Distribution: NLP, Emmet; Isle Royals (Prescott 1940 fa.). var. brachylobum Wittr. Krieger, 1937. Rabh. Krypt. Flor. l3(1):537. P1. 72, Figs. 8, 9. 158 This variety has the lateral and polar lobes less developed than the typical. There is only one single facial swelling on the apical lobes, in contrast to two in the typical. Measurements: L. 55-(64)-84; W. 37-(47)-56u; I. 9-(9)- 15u; A. 21-32u. Distribution: NLP, Cheboygan (Taft 1939); EUP, Delta; WUP, Iron. var. rostratum Taylor Krieger, 1937. Rabh. Krypt. Flor. l3(1):539. P1. 73, Figs. 4,5. This variety has the margins of the reduced lateral lobe converging towards the sinus and the basal lobe rostrate in a median lateral line. Measurements: L. 70u; W. 44.8-52u; I. 12u; A. 22u. Distribution: EUP, Alger, Delta; WUP, Menominee; Isle Royale (Prescott 1940, var. braghyTobum fa. rostratum). var. inevolutum West and West Krieger, 1937. Rabh. Krypt. Flor. l3(1):538. P1. 72, Figs. 12, 13. This variety appears to be a reduced form of the typical. The cells are smaller, the basal lobes are more quadrate, and the polar lobe is relatively broader and shorter with the apex more convex and retuse in cen- tral portion, and with the apical angles more rounded. In the vertical view, the facial swellings are reduced from the size of the typical. 159 Measurements: L. 42-68.4u; W. 33-45.6u; I. 6-15.5u; A. 24-30u. Distribution: _Isle Royals (Prescott 1937). 27. var. scrobiculatum Prescott Prescott, 1940. Pap. Mich. Acad. Sci. Arts and Letters. 25:98. P1. 1, Fig. 22. This variety has a very short polar lobe with a convex apex. The wall is coarsely scrobiculate, and there is a single facial swelling within the margin of each lateral and basal lobe. Measurements: L. 73-76.4u; W. 47-49.4u; I. 15.2u. Distribution: Isle Royale (Prescott 1940). 28. Euastrum attentuatum Wolle Krieger, 1937. Rabh. Krypt. Flor. l3(1):541. P1. 73, Figs. 15-17. The apical crown of granules separates this from other Michigan species of Euastrum. Measurements: L. 61-67u; W. 35-45u; I. 12-13u; 4- ll-l3u. Distribution: NLP, Cheboygan (N & A 1932); Isle Royale (Prescott 1937). 29. var. lithuanicum Wolosz. fa. Krieger, 1937. Rabh. Krypt. Flor. l3(1):542. P1. 73, Figs. 18, 19. This variety has a less exserted and broader apical lobe than the typical. In addition, it has in side view, a 2-3 parted facial swelling, whereas the typical has a greatly reduced facial swelling that is two parted. cla- lbO Measurements: L. 59.5-65u; W. 35.l-#Ou; I. 11.7-l4u. Distribution: Isle Royale (Prescott 1940). 3Q. Euastrum sublobatum Naegli. Pl. 5, Fig. 7. Krieger, 1937. Rabh. Krypt. Flor. 13(1):5#4. Pl. 74, Figs. 1-3. This variety is about 1 1/2 times longer than wide. This characteristic and the truncate apex (in side view) separate it from g, binale. The apical angles are usu- ally broadly rounded whereas in g, binale they are usu- ally sharply angled. Measurements: L. 18-30u; W. l3—2l.5u; I. 3-8u. Distribution: WUP, Gogebic. New record for Michigan. 31. var. obtusatum (Gutw.) Krieger Pl. 5, Fig. 6. Krieger, 1937. Rabh. Krypt. Flor. 13(1):545. P1. 74, Figs. 9-11. This variety is relatively longer than the typical. The apex is slightly emarginate and the central facial swelling is lacking. Measurements: L. 18-26u; w. 8-l7u; I. 3-5u; A. 8.4u. Distribution: WUP, Marquette. New record for Michigan. 32. Euastrum crassangulatum Boerg. Krieger, 1937. Rabh. Krypt. Flor. 13(1):546. Pl. 7n, Figs. 12-14. This Species can be distinguished by the large cen- tral facial swelling of the semicell wall, and by a smaller swelling on each of the apical and basal lobes. v...- 161 Measurements: L. 25-28u; W. 17-19u; I. 5-6u; A. 12u. Distribution: Isle Royale (Prescott 1937). 33. Euastrum validum West and West Krieger, 1937. Rabh. Krypt. Flor. 13(1):54 . P1. 74, Figs. 18-20. The presence of a pore in the central region of the semicell wall and the isthmial papillae easily separates this species from g, binale and g, bipapillatum. A small papilla within each basal angle is also characteristic of this species. Measurements: L. 25-(25.8)-(28)-30u; W. 18-(19.3)-22u; I. 3.6-(4.2)-6u; A. 13.5—14.5u. Distribution: SLP, Calhoun, Berrien; EUP, Schoolcraft; WUP, Gogebic (2); Isle Royale (Prescott 1937). 34. var. glabrum Krieger P1. 5, Fig. 8. Krieger, 1937. Rabh. Krypt. Flor. l3(1):547. P1. 74, Figs. 21, 22. This variety is separated from the typical by the lack of papillae in the angles of the basal lobes. Our specimens were slightly shorter and narrower than the typical measurements. Measurements: L. (23.6)-29u; W. (l7.2)-l9u; I. (3.8)-4.8u. Distribution: SLP, Calhoun; EUP, Schoolcraft. New re- cords for Michigan. 35- lggastrum binale (Turp.) Ehrenb. Pl. 6, Fig. 3. Krieger, 1937. Rabh. Krypt. Flor. l3(1):548. P1. 75, Figs. 1-3. 162 E3 binale is very closely related to g, sublobatum. It differs from this species in relative smaller length, being about 1 1/5 - 1 1/4 times longer than wide. The basal angles are much broader and the apical angles are usually sharply angles. The apex is slightly emarginate, whereas 2, sublobatum has the apex broadly and shallowly retuse. In addition, the lateral view of the semicell is elliptic in contrast to the irregular rectangular shape of E, sublobatum. Measurements: L. lO-(21.5)-23u; w. lO-(15)-23u; I. 3-(3-5)- 9u; A. lO-12u. Distribution: EUP, Chippewa; WUP, Gogebic. New record for Michigan. 36. var. hl§2§_ w. West Krieger, 1937. Rabh. Krypt. Flor. 13(1):551. P1. 75: Fig. 16. The basal angles of this variety are obliquely trun- cate toward the sinus. Measurements: L. 11-17.5u; W. 10-15.5u; I. 2.5-5u. Distribution: NLP, Cheboygan (Taft 1939). 37. var. Gutwinskii Schmidle Krieger, 1937. Rabh. Krypt. Flor. 13(1):551. P1. 75, Figs. 13-15. This variety is generally somewhat larger than the typical. There are also two undulations in the lateral margin between the apical and basal angles. 163 Measurements: L. l6-(25.8)-30u; W. 12-(19.2)-21u; I. 3-(4.3)-6.5u; A. about llu. Distribution: SLP, Ingham (N & A 1932); EUP, Chippewa, Schoolcraft; WUP, Gogebic (2), Baraga (2), Houghton. 38. Euastrum insulare (Wittr.) Roy Krieger, 1937. Rabh. Krypt. Flor. l3(1):555. P1. 76, Figs. 11-14. The cell of this species is about 1 1/2 times longer than broad; the basal portion of the semicell is rectang- ular and the lateral margin has a single undulation be- tween apical and basal angles. The apex is slightly emarginate and the apical angles are rounded or slightly cuspidate. The semicell wall has a smooth central swelling. Measurements: L. l7.5-(23)-31u; W. 11.5-(l7)-22u; I. (3)‘ 3-6u. Distribution: SLP, Livingston, Barry, also Macomb (John- son 1894, Pieters 1894, g, binale var. insulare); NLP, Cheboygan (N & A 1932); EUP, Chippewa, Alger; WUP, Men- ominee, Houghton, Marquette, Gogebic. 39. ggastrum bipapillatum Gronbl. Pl. 6, Fig. 8. Krieger, 1937. Rabh. Krypt. Flor. l3(1):562. P1. 80, Figs. 13, 14. Characteristically, this species has trapeziform semicells, base wide, apex slightly emarginate, a single marginal undulation between the basal and apical angles, a single papilla in the central region of the semicell, 164 and another at the isthmus. Michigan specimens are slightly smaller than typical measurements. Measurements: L. (25.5)-28-30u; w. (19)-21u; I. 4.2u. Distribution: NLP, Emmet. New record for North America. 40. Euastrum sibiricum Boldt. Pl. 6, Fig. 4. Krieger, 1937. Rabh. Krypt. Flor. l3(1):566. P1. 77, Figs. 1-3. The following characteristics separate this species from other Michigan species. It is slightly longer than broad, the apical and lateral lobes possess short spines, the central facial region of the semicell wall is orna- mented with a papilla and two short spines are inserted within margin at the apex, one on each side of the slight apical emargination. Michigan specimens are slightly larger than typical measurements. Measurements: L. 15.6-20-(21.5)u; W. ll-l6-(l9.3)u; I. 3-(4.3)-6u; A. lO-llu. Distribution: SLP, Barry. New record for Michigan. 41. Euastrum dubium Naeg. Krieger, 1937. Rabh. Krypt. Flor. l3(1):57l. Pl. 79, Figs. 1-5. This extremely variable species is about 1 1/2 times longer than wide. The semicells are elongate-trapeziform with the apex either emarginate or with a moderately deep linear sinus. The lateral margins have a single undula- tion between the apical and basal lobes. The semicells 165 have a granule within each apical angle, sometimes within each lateral and basal angle. The central facial area of the semicell may have three granules or be smooth. The variety Snowdoniense is included as part of the typical here. Measurements: L. 25-(28)-38u; W. l7-(21.5)-26u; I. 3- (4.3)-8u; A. 11.5-15u. Distribution: SLP, Calhoun, Barry (3); NLP, Crawford, also Cheboygan, Emmet (N a A 1932), Cheboygan (N a A 1932, var. Snowdoniense); EUP, Schoolcraft, Mackinac. 42. Euastrum crassicolle var. bicrenatum de Toni Krieger, 1937. Rabh. Krypt. Flor. l3(1):576. P1. 78, Figs. 15, 16. This variety cannot be confused with any other species reported from Michigan. Characteristically, this species has cells 1 3/4 - 2 times longer than wide, the semicells being somewhat truncate pyramidate in shape. The polar lobe is rounded and the apex is slightly retuse. The lateral margin has a single undulation between the basal and apical angles. Measurements: L. 26-34u; W. 13.8-18u: I. 4.5-8.8u; A. 8-l2u. Distribution: EUP, Marquette (Pres. & Mag. 1935, g, ghigg- eringii Prescott). 43. Egastrum incrassatum Nordst. Krieger, 1937. Rabh. Krypt. Flor. l3(1):582. Pl. 85, Figs. 16-18. 166 This species is sharply differentiated from other Michigan species by the entirely undulate lateral margins. Measurements: L. 29-40u; W. 19-26u; I. 6-ll.4u. Distribution: Isle Royale (Prescott 1940). 44. Euastrum denticulatum (Kirchn.) Gay Krieger, 1937. Rabh. Krypt. Flor. l3(1):80. P1. 80, Figs. 15-17. This species has cells about 1 1/5 times longer than broad. The semicell is trapeziform with the apex possess; ing a short median incision and short lateral spines. The lateral lobe is absent. The central region of the semi- cell wall has a circle of three elongated granules. Some- times there are two semicircular granules between the central granules and the isthmus. The basal and apical lobes also have a number of granules within the margin. Some of Michigan specimens have five central granules and lack the supra isthmial papilla. Measurements: L. l9-(30)—32u; W. l4—(24.5)-25u; I. 3-(4.3)-8u; A. 12-16u. ° Distribution: SLP, Livingston, Calhoun, Berrien, also Muskegon (Transeau 1917); NLP, Cheboygan (N & A 1932), Emmet (Transeau 1917). 45. var. angusticeps Gronbl. Pl. 6, Fig. 7. Krieger, 1937. Rabh. Krypt. Flor. 13(1):584. P1. 80, Figs. 18, 19. This variety has a narrower apex than the typical. The apex is scarcely dilated. The central facial swelling 167 in the semicell wall may be smooth or bear (usually) four elongate granules in a circular pattern. The Mich- igan specimens have three granules, and one specimen has two supra isthmial granules. Measurements: L. 19-(21.3)-25u; w. 15-(19)-20u; I. (4.3)-4.5-5.3u. Distribution: EUP, Schoolcraft; WUP, Gogebic. New record for Michigan. 46. Euastrum trigibberum West and West Krieger, 1937. Rabh. Krypt. Flor. l3(1):585. P1. 80, Figs. 24-26. This small species is about 1 1/5 times longer than wide. The semicell is trapeziform.with deep median in- cision. The lateral margin has the basal lobe separated from the apical lobe by a deep semicircular incision. In the writer's Michigan specimens, the basal lobe is sub- divided into two smaller lobules giving the semicell an almost trilobed appearance. The apical lobes each have a slight subapical marginal projection and a pair of granules. The central facial area has a circle of five small granules, and the basal areas each have four to six granules arranged in a somewhat elliptical pattern. Measurements: L. 23-99-(32)u; W- l9-23-(23.5)u; I. (6.3)-6.5-7u; A. 14-15.5u. Distribution: NLP, Cheboygan (N & A 1932); WUP, Gogebic (fa.). 168 47. Euastrum pulchellum Breb. Krieger, 1937. Rabh. Krypt. Flor. 13(1):587. P1. 81, Figs. 8-11. This species resembles g, abruptum but never has the basal width greater than the width of the semicells at the lateral lobes. Measurements: L. 30—4lu; W. 20-30u; I. 4-7.3u; A. 15-20u. Distribution: NLP, Cheboygan (Taft 1939). 48. Euastrum Turneri W. iest Krieger, 1937. Rabh. Krypt. Flor. l3(1):589. P1. 82, Figs. 20, 21. This species superficially resembles g, trigibberum from which it can be easily separated by its relatively greater lengthewidth ratio, and by the presence of two mucilage pores above the central granular region of the semicell wall. The basal and lateral lobes are always distinct in this species although they are not greatly exserted. Measurements: L. 33-(44.6)-50u; W. 25-(30.5)-33u; I. 6-(6.7)-llu; A. 18-23u. Distribution: SLP, Barry, also Kalamazoo, Washtenaw (N a A 1932). 49. (Egastrum elegans (Breb.) Kuetz. Krieger, 1937. Rabh. Krypt. Flor. l3(1):59l. P1. 81, Figs. 14—18. This species can be differentiated easily by the obliquely truncate apical lobes, and the truncate, slightly 169 retuse basal lobes. It is closest to g, bidentatum from which it is easily distinguished by the lack of a lateral lobe. Measurements: L. 23-(30)-44u; W. l4-(2l)-29u; I. 4-(4.3)-8u; A. about 15-16u. Distribution: SLP, Washtenaw, also Wayne (Campbell 1886) and Macomb (Pieters, 1894); NLP, Emmet; WUP, Menominee, Gogebic (2); Isle Royale (Prescott 1937). 50. Euastrum divaricatum Lund. Krieger, 1937. Rabh. Krypt. Flor. l3(1):598. P1. 84, Figs. 1-5. This species is sharply distinguished by the triang-‘ ular-trapeziform shape of the semicell, and the single large horizontally directed spine at each supra basal margin. Measurements: L. 35-(43)-46.8u; W. 27-(36.5)-37u; I. 5-(6.4)-10u; A. l4-20u. Distribution: WUP, Gogebic; Isle Royale (Prescott 1937). 51. Euastrum bidentatum Naeg. Krieger, 1937. Rabh. Krypt. Flor. l3(1):601. P1. 85, Figs. 1, 2. This species has a resemblance to g: elegans but is sharply differentiated from it by the presence of a (sometimes slight) lateral lobe. The ornamentation on the semicell wall is highly variable. Krieger (1937) states that the typical has (in the central region of 170 the semicell face) three long granules lying parallel to each other and to the long axis of cells. These are above a single long granule lying in transverse position. The writer believes that because of the great variability of the central granulation found in his Michigan speci- mens and because of the similar observations made by West and West (1905), it is more satisfactory to include under the typical forms which agree with other typical charac- teristics, but which have a different central granulation. g, elegans var. bidentatum (Naeg.) Jacobson, and g, ros- tratum Ralfs., also should be included here. Measurements: L. (45)-45-(60)-(62.5)-64u; W. (26)-27-(38)- 4lu; I. 6.9-(8.5)-l3u. Distribution: SLP, Calhoun, Ingham, Oakland, Barry (2), Washtenaw; NLP, Emmet, Crawford, also Cheboygan (N a A 1932); EUP, Delta, Alger, also Schoolcraft (N & A 1932, also as g, rostratum), also Schoolcraft (Transeau 1917); WUP, Marquette, Iron, Houghton, Menominee; Isle Royals (Prescott 1937). 52. Euastrum lapponicum Schmidle fa. P1. 6, Fig. 10. Krieger, 1937. Rabh. Krypt. Flor. 13(1):604. P1. 85, Figs. 8, 9. This species typically has a trapeziform semicell with the lateral lobe forming a distinct undulation on the lateral margin. The apex has a medium deep, slightly open median incision, and the apical angles bear small 171 horizontally directed spines. Typically the lateral and basal lobes bear small granular spines on the margin, and single, larger, semicircular granules within the margin. The central area of the semicell face has two elongate granules which may be subdivided once or twice. The few Michigan specimens from Slhoolcraft County, agree favor- ably with the forma illustrated by Prescott and Scott (1945) from.Mississippi. This forma has a deeper apical incision and the central facial region has only a single large granule. In addition, the lobular granulation is relatively more reduced, and the plant is slightly smaller than the typical. This forma should be compared with E3 dubium. Measurements: L. (33)-36-43u; W. (21.3)-24-30u; I. (4.2)—8u. Distribution: EUP, Schoolcraft. New record for Michigan. 53. Euastrum abruptum Nordst. Pl. 6, Fig. 9. Krieger, 1937. Rabh. Krypt. Flor. 13(1):605. P1. 83, Figs. 1-3. This species has trapeziform semicells with the semicell width at the lateral lobes usually larger than the width at the basal lobes. The only Specimens ex- amined were from Oakland County and agree more favorably with illustrations of Prescott and Scott (1945), than with those of Krieger (1937)- 172 Measurements: L. 37-(42)-60u; W. (25.5)-27-40.5u; 1- (4.5)-7-9u; A- 31-36u. Distribution: SLP, Oakland. New record for Michigan. 54. Euastrum Ciastonii Racib. Pl. 6, Fig. 11. Krieger, 1937. Rabh. Krypt. Flor. l3(1):607. P1. 84, Figs. 14, 15. Typically, this species has semicells that are al- most rectangular with the lateral lobular undulations (sometimes lacking) possessing 3—4 granules. The deep linear apical incision and the characteristic granular decoration of the semicell wall also distinguish this species easily. Michigan specimens from several counties exhibit a more pronounced undulation on the lateral mar- gin than shown in Krieger's (1938) illustration, and agree more favorably with illustrations of this species by Irenee-Marie (1938), and Prescott and Scott (1945). Measurements: L. 38-(45)-57u; W. 21-(25)-29u; I. 4.5-(5)-10u; A. 17—22u. Distribution: SLP, Barry (2); EUP, Schoolcraft; WUP, Gogebic (3). New records for Michigan. 55- Euastrum evolutum (Nordst.) West and West Krieger, 1937. Rabh. Krypt. Flor. 13(1):614. P1. 87, Figs. 15, 16. This species is very characteristic and cannot be confused with other species of Euastrum. The presence of an accessory lobe with spines on the lateral margin a short distance below the apical angle, separates it 173 from most species. The middle-sized cell (over 50u), is about 1 1/2 times longer than wide, with the semicell elongate-trapeziform. The apex has a deep linear to slightly open median incision, and the apical angles bear single spines. The lateral margins have the lobes separ- ated by open (sometimes deep and narrow) sinuses. The central facial area of the semicell wall has three elongate granules arranged in a somewhat circular pattern with two mucilage pores a short distance above. The three lateral lobes bear small granular teeth. ieasurements: L. 58.5-75u; w. 37—58u; I. 10-15u; A. 30-32u. Distribution: Isle Royale (Prescott 1937). 56. var. integrius West and West Krieger, 1937. Rabh. Krypt. Flor. 13(1):616. P1. 88, Figs. 4-6. This variety is separated from the typical by the lack of a distinct lateral lobe, and by the presence on the subapical margin of a large horizontally directed spine instead of an accessory lobe. Measurements: L. 46-(54.2)-6lu; W. 31-(38.3)-4lu; I. (6.4)-7-lOu; A. 24-3lu. Distribution: NLP, Cheboygan (N & A 1932); EUP, School- craft; WUP, Houghton. 57. var. Glaziovii (Boerges.) west and west Pl. 7, Fig. 3. Krieger, 1937. Rabh. Krypt. Flor. 13(1):615. P1. 88, Figs. 1-3. 174 This variety, like var. integrius has the accessory subapical lobe replaced by a spine. The lateral lobe is less Sharply separated than the typical. The apical sinus is almost closed at the outer margin, but opens widely internally to form an elliptic space between the apical lobes. The central facial area of semicell wall may be smooth or bear three granules as in the typical. Measurements: L. 55-(64)-68.5u; W. 34-(36)-43u; I. 6.5-(10.6)-1lu; A. 35-40u. Distribution: NLP, Emmet; EUP, Schoolcraft. New records for Michigan. 58. var. guianense (Raéb.) west and West P1. 7, Fig. 2. Krieger, 1937. Rabh. Krypt. Flor. 13(1):615. P1. 87, Fig. 21. This variety is somewhat smaller than the typical. The accessory subapical lobe is reduced either to a slight marginate protuberance, or a less exserted lobe. The lateral and basal lobes are less exserted and the granular teeth are reduced. It appears essentially to be a slightly smaller, reduced form of the typical. Measurements: L. 42-(45)-47u; W. 23-32—(32)u; I. 5-(6.4)-8u. Distribution: EUP, Schoolcraft. New record for Michigan. 59. Euastrum oculatum.var. tonsum West and West Pl. 6, Fig. 6. Krieger, 1937. Rabh. Krypt. Flor. 13(1):618. P1. 87, Figs..12-l4. This organism characteristically has cells which are almost twice as long as wide, the semicells being elongate 175 trapeziform in shape. The apex has a medium-deep inci- sion, opened or linear, and the apical angles each bear a large divergent spine. The lateral margin has the lat- eral lobe slightly exserted and bear short granular spines. The basal lobes have similar spines at the angles. The semicell wall has several granules within the lateral margin at each pole and also a large single (rarely sev- eral) central one. Typically, there are two mucilage pores above the central granule. Measurements: L. 38.5—(45)-48u; W. 24-(29.2)-30u; I. (5.5)-5.6-8u. Distribution: WUP, Gogebic (3). New record for Michigan. 60. Euastrum gemmatum Breb. Krieger, 1937. Rabh. Krypt. Flor. 13(1):639. P1. 92, Figs. 5-8. This species cannot be confused with any other Michigan species of Euastrum. The cell wall granulation easily separates it from g, pectinatum and varieties, and the quadrate shape of the lower half of the semicell and the smaller size distinguishes it from.§, verrucosum. Measurements: L. 43~(56.6)-72u3 W- 37—(39)-52u; I. 8-(lO.9)-15u; A. 15-21u. Distribution: SLP, Barry, also Muskegon (Transeau 1917); NLP, Roscommon also Cheboygan (Neal 1948); EUP, Alger. 61. Egastrum verrucosum. Ehrenb. Krieger, 1937. Rabh. Krypt. Flor. 13(1):643. P1. 94, Figs. 1-3. 176 Some of the more prominent characteristics of this species are the trapeziform shape of the semicell, the three lobes on the margin that are separated by deep and open sinuses and the cuneate apex which is broadly retuse. The facial area of semicell wall is furnished with a trans- verse row of three protuberances, each ornamented with granules arranged in concentric circles. The semicell wall is granulate, especially so in the angles where the granules are often sharp and conical. Measurements: L. 74-115u; W. 65-103u; I. l7-30u; A. 25-42u. Distribution: SLP, Berrien (Transeau 1917), also Wayne (Campbell 1886 and Macomb Pietees 1894); NLP, Roscommon, also Cheboygan (N & A 1932); EUP, Alger, also Chippewa (N a A 1932); Isle Royale (Prescott 1937). 62. var. alatum Wolle Pl. 7, Fig. l. Krieger, 1937. Rabh. Krypt. Flor. 13(1):645. P1. 94, Fig. 4. This variety differs from the typical in having the inner portion of the median sinus linear and closed, and the outer portion widely open. Measurements: L. 72-(78.8)-110u; W. 60-(6l.7)-108u; I. 14-(19)-22u; A. 22-38u. Distribution: SLP, Washtenaw; EUP, Schoolcraft; WUP, Houghton, Gogebic (2). New records for Michigan. 63- var. planctonicum. West and West Krieger, 1937. Rabh. Krypt. Flor. 13(1):649. P1. 95, Fig. 7. 177 This variety differs from the typical and from var. alatum by having a widely open sinus. The lateral lobes are also lacking. Measurements: L. 90u; W. 9lu: I. 19.5u. Distribution: SLP, Berrien (Transeau 1917). 64. var. vallesiacum Veret Krieger, 1937. Rabh. Krypt. Flor. 13(1):653. P1. 96, Fig. 8. This variety is distinguished from the typical by the more nearly semicircular shape of the semicells and the shorter lobes which are broadly rounded. The sinus between the semicells is linear and then.widely open outwardly. Measurements: L. 73-88u; W. 57-69u; I. 12-15u. Distribution: EUP, Chippewa (Ackley 1929, N & A 1932, var. sublongum.Ackley)- 15. COSMARIUM Corda 1834 Cells variable in size, usually with the length not more than twice the width, rarely with the width greater than the length, median constriction usually deep and linear. Semi- cells of variable shape, often circular, semicircular, ellip- tic trapeziform, reniform, or subquadrate in front view (usu- ally compressed but rarely with lateral protuberances in side View). Cell wall smooth, punctate, or ornamented.with granules 0r verrucae (never with spines), the ornamentation often ar- 178 ranged in definite patterns. In vertical view, cells generally elliptic, rarely with lateral protuberances. Chloroplast gen- erally single and axial and with form radiating plates in each semicell, rarely two axial or four-parietal chloroplasts in each semicell; pyrenoids usually single and central in each chlorOplast. Zygospores usually spherical or ellipsoidal, more rarely angular with walls that are smooth or ornamented with papillae or spines. Key to Species of Cosmarium Cell wall smooth, punctate or scrobiculate; margins usu- ally entire, sometimes crenate, but never with granules; papillae sometimes present on face or on isthmus . . . . O O O O O O. O 0 O O O O O O O O O O 0 O O I O Osection A Cell wall ornamented with granules, verrucae or papillae . . . . . . . . . . . . . . . . . . . . . . . .Section B Section A Semicells semicircular or subsemi- circular . . . . . . . . . . . . . 2 Semicells not semicircular or sub- . semicircular . . . . . . . . . . . 14 2. Semicells with blunt submammil-' late thickenings at the basal angles . . . . . . . . . . . 3 2. Semicells without blunt submam- millate thickenings at the basal angles . . . . . . . . 4 Width of isthmus more than 15u . . . (l) §;_obsoletum Width of isthmus less than 15u . . . (143) g, taxichondrum var. nudum.(l42) and var. unigranulatum 7. Ce (.0 9. 11. 11. 179 4. Margins of semicells undulate or crenate . . . . . . . . . 5 4. Margins of semicells not undu- late or crenate . . . . . . . 6 d . Intgmarginal crenations present . .(2)C _. cyclicum Intramarginal crenations not present (4) g, undulatum 6. One or more scrobiculations present in central area of semicells . . . . . . . . . . 7 6. No scrobiculations present in central area of semicells . . 8 Cells large, length more than 50u; scrobiculations numerous, more than 10 . . . . . . . . . . . . . (9) 9: perforatum Cells small, length less than 50u; scrobiculations less than 10 . . . (8) g, ocellatum fa. 8. Walls of semicells very thick (205-311) 0 o o o o o o o o o 9 8. Walls of semicells not conspi- cuously thickened . . . . . . 10 Width of isthmus usually less than 27u; lateral margin slightly undu- late-crenate; wall with conspicuous pores . . . . . . . . . . . . . . (16) g, tuddalense Width of isthmus more than 28u; lat- eral margin entire; wall with con- spicuous punctations . . . . . . . (10) g, pachydermum 10. Cell length more than lOOu . . (11) g, Ralfsii 10. Cell length less than lOOu . . ll Semicells semicircular . . . . . . . (13) g, circulare Semicells subsemicircular or pyra- 13 midate-SBIniC 1rcu1ar o o o o o o 12. Apices retuse . . . . . . . . . (124) g, laeve 12. Apices not retuse . . . . . . . l3 13. 13. 15. 15. 17. 17. 19. 19. 21. 21. Constriction very deep, more than one half the distance to center of semicell, sinus linear . . . Constriction less deep, less than one half the distance to center of semicell, sinus acute . . . . . l4. Semicells semi-elliptic, con- striction well-defined and deep . . . . . . . . . . . . l4. Semicells not semi-elliptic, constriction variable . . . . Lateral margins undulate . . . . . . Lateral margins not undulate . . . l6. 16. Cell length more than 75u . . Cell length less than 75u . . . Cell width more than 20u . Cell width less than 20u . . . . . . 18. Semicell with 6-8 parietal chloroplasts . . . . . . . l8. Semicell with a single axial chloroplast . . . . . . . . . Semicells circular or subcircular, rarely subelliptic . . . . . . . . Semicells Otherwise 20. Constriction conspicuous and fairly deep . . . . . . . . . 20. Constriction slight . . . . . . Cell length more than 45u . . . . . Cell length less than 45u . . . . . 22. Semicell elliptical in vertical View 0 O O O O O O O O O I O 22. Semicell circular or subcircular in vertical view . . . . . . 180 (14) C. Lundelli . var. Ellipticum (15) g, canadense 15 19 subundulatum l6 (16) g, tuddalense 17 18 (23) g, moniliforme fa. elongata (l7) 9; (19) g: cucumis (18) 93 subcucumis 20 27 (20) g, moniliforme 21 25 22 24 23 23. 23. 27. 27. 29. 29. 31. 31. 181 Cell wall with sparsely scattered punctations . . . . . . . . . . . (27) g, subtile Cell wall without sparsely scattered punctations . . . . . . . . . . . (32) g, globosum 24. Length of cell 15-2lu, with. of cell l2-l7u . . . . . . .(31) C. subarctoum 24. Length of cell 10.5-14.6u, width of cell 9-l2u . . . . . (38) g, inconspicuum Length of semicell 65u or more . . . 26 Length of semicell less than 65u ... (35) g, pseudoconnatum 26. Cell wall finely scrobiculate with minute punctations be- tween the scrobiculations, '/ constriction moderate . . . . (30) g, connatum 26. Cell wall finely punctate, con- striction slight . . . .(37) C. alpestre Semicells cylindrical, subcylindrical or fusiform-cylindrical; constric- tion very slight . . . . . . . . . 28 Semicells otherwise . . . . . . . . 33 28. Cell length more than 20u . . . 29 28. Cell length less than 20u . . . (27) 93 subtile Cell length more than 75u . . . . . 3O . . . 31 Cell length less than 75u . . 30. Semicell wall thickened at apices . . . . . . . . . . (26) g, diplospora var. ma or 30. Semicell wall not thickened at apices . . . (30) C. elonma atm (cf. (29) C. cucurbitinum or) Semicell wall thickened at apices. . (25) g: difiplospora Semicell wall not thickened at apices . . . . . . . . . . . . . . 32 33- 33- 35- 35. 37. 37- 39. 39. 41. 41. 182 32. Cell length more than 50u . . . (29) g, cucurbitinum var. minor 32. Cell length less than 50u . . . (28) g, cucurbita Semicells transversely elliptic, ob- long elliptic, reniform or subhex- agonal-elliptic . . . . . . . . . 34 Semicells otherwise . . . . . . . . 43 34. Semicells transversely and nar- rowly elliptical-oblong or subhexagonal elliptic . . . . 35 34. Semicells transversely ellipti- cal or elliptical-reniform . 37 Sinus closed . . . . . . . . . . . . 36 Sinus open . . . . . . . . . . . . . (40) g, depressum var. reniforme 36. Cells small, length less than 25u . . . . . . . . . . . . . (41) 9: subdepressum 36. Cells larger, length more than 30u . . . . . . . . . . . . . (39) g, depressum var. achondrum Sinus closed . . . . . . . . . . . . 38 Sinus open . . . . . . . . . . . . . 39 38. Cell length more than 30u . . . (M) 9. W 38. Cell length less than 30u . . . (42) g, phaseolus var. minor and (43) var. elevatum Cell length more than 30u . . . . . 40 Cell length less than 30u . . . . . 41 40. Semicell with three lateral un- dulations in vertical view . (45) g, sulcatum 40. Semicell without three lateral undulations invvertical view. (46) 9: contractum Width of semicells up to l2u . . . . 42 Width of semicells l3u or more . . . (49) g, bioculatum 43. 43. 45. 45. 47. 47. 49. 183 . subarctoum) 42. Apex of sinus obtuse . . . . . (cf. (31) g Q, inconspicuum 42. Apex of sinus acute . . . . . . (48) g, tinctum Semicells pyramidate or subpyramidate, apices usually truncate . . . . . 44 Semicells not pyramidate or subpyra- midate, apices variable . . . . . 74 44. Lateral margins sharply constric- ted a short distance below and causing a dilation of the apex(5l) Q, Holmiense 44. Lateral margins otherwise . . . 45 Lateral margins crenate or undulate. 46 Lateral margins not crenate or un- dulate; either straight, retuse or biundulate in upper part only, or convex . . . . . . . . . . . . . . 53 46. Semicell with a supraisthmial granule or papilla . . . ... 47 46. Semicells without a supra- isthmial granule or papilla . 48 Semicells more than 35u . . . .(53)C . tetragonum. var. Lundelli Semicells less than 35u . . . .(61)C . trilobulatum var. basichondrum 48. Middle area of semicell wall with : a distinct scrobiculation . . 51 48. Middle area of semicell wall with- out a distinct scrobiculation * 49 Each lateral margin with about eight undulations . . . . . . . . (55)C _. obtusatum Each lateral margin with three or four undulations (including apical and basal angle) . . . . . . . . . 5o 50. Lateral undulations 3 . . .(56)C _. venustum 50. Lateral undulations 4 . . . . . (58) g, impressulum 51. 51. 53- 53. 55. 55. 570 57. 59. 59. 184 Width of semicell below 20u . . . . 52 Width of semicell above 20u . . . . (57) g: venustum var. excavatum fa. duplo-major 52. Length of cell under 25u . . . (62) g, trilobulatum var. retusa 52. Length of cell over 25u . . . . (63) g, subreinschii var. ocellatum Upper lateral margins retuse, subre- tuse or biundulate . . . . . . . . 54 Upper lateral margins not retuse or subretuse . . . . . . . . . . . . 61 54. Basal angles rectangular . . . 56 54. Basal angles broadly rounded .- 55 Cell length more than 35u . . . . . (64) g, Hammeri Cell length less than 35u . . . . . (66) g, retusiforme 56. Apical lobes distinctly retuse. (67) g, Pokornyanum 56. Apical lobes flattened or very slightly concave . . . . . . 57 Lower lateral margins slightly di- vergent . . . . . . . . . . . . . 58 Lower lateral margins not divergent. 59 58. Upper lateral margin with one or two undulations . . . . . (69) g, granatum var. subgranatum 8. U er lateral mar in retuse . . (cf. (79) C. scopulorum) 5 pp g (60) g, trilobulatum Upper lateral margin straight . . . (68) g, granatum Upper lateral margin retuse or sub- retuse o o o o 0 o o o o o o o o o 60 60. Lateral margin with two sides f. (:9) C. scopulorum) r 16bulatum 60. Lateral margin with three sides . . . . . . . . . . . . (96) g, angulare var. octangulare 61. 61. 63. 63. 65. 65. 67. 67. 69. 69. 185 Semicells pyramidate-semicircular . (70) g, subtumidum Semicells not pyramidate-semicir- cular O O O O O O O o O O O O O O 62 62. Cell as long as wide or slightly (up to 1 1/4 times) longer than wide . . . . . 63 62. Cells distinctly (1 1/3-1 3/4 times) longer than wide . . . 66 Length of cell more than 50 u . . . 64 Length of cell less than 50u . . . . 65 64. Width of apices 15-l7u . . (73) Q3 galeritum 64. Width of apices 20-28u . . . . (75) g, pseudonitidulum var. validum ‘ Two pyrenoids present in each semi- cell . . . . . . . . . . . . . . . (74) Q3 pseudonitidulum A single pyrenoid present in each semicell . . . . . . . . . . . . . (76) g, nitidulum 66. Cells small, less than 35u . . 67 66. Cells larger, more than 35u . . 69 Apices flat . . . . . . . . . . . . (68) g, granatum 3 Apices retuse . . . . . . . . . . . 68 68. 8923155: W515 coarsely scrobi-. (78) g. variolatum fa. 68. Semicell wall finely punctate or punctate-scrobiculate . . (124) g, laeve Central area of semicell wall with a large pore . . . . . . . . . . . . (77) g, variolatum fa. var. cataractarum Central area of semicell wall with- 70 out a large pore . . . . . . . . . 70. Sinus shallow . . . . . . . . . 71 70. Sinus deep . . . . . . . . . . 72 71. 71. 73. 73- 75- 75. 77. 77. 186 Width of semicells greater than the length of the semicell . . .(72)C . capense fa. minor Width of semicells about equal to or less than the length of the semi- cell . . . . . . . . . . . . .(80) C. maculatum 72. Lower lateral margin perpendi- cular to base, upper lateral margin strongly convergent to apex . . . . . . . . . . .(68) C. granatum 72. Lateral margins convex and grad- ually converging to the apex. 73 Semicells with a single pyrenoid . . (83) C. pseudopyrami- Eatum Semicells with two pyrenoids . . . . (81) 93 pyramidatum 74. Semicells rectangular or sub- rectangular in outline . . . 75 74. Semicells elliptic hexagonal, subhexagonal or polygonal . . 85 Apices of semicells with about six undulations between each of which there is a short vertical linear thickening of the wall . . . . . . (113)C . humile var. striatum Apices of semicells with entire or crenulate-undulate margins but never with wall thickenings as above . . . . . . . . . . . . . . 76 76- Margins of semicells entire . . 77 76.. Margins of semicells crenate or undulate . . . . (of. (128) C. Regnesii var. tritum) (169) C. novae-semliae var. sibeficum Constriction very slight . . . .(86)C . arctoum var. tatrica Constriction fairly deep . . . . 78 78. Semicells distinctly longer 82 tmn Wide 0 o 0 0 ' ’ ' 78. Semicells as long as widefrwider than long . . . . . . . . . . 79 79- 79- 81. 81. 83. 83. 85. 85. 87. 187 Cell length 8-lO.5u . . . . . . . . (87) 9, minimum Cell length more than 10.5u . . . . 8O 80. Cell small, length less than 3011 o o o o o o o u o o o o o 81 80. Cell larger, length more than 30u . . . . . . . . . . . . (108) C. rectangulare Lateral margins slightly retuse . .(88) C. norimbergense fa. depressa Lateral margins not retuse . . . . . (89) g, exiguum 82. Cell length more than lOOu . . (90) g, Debaryi 82. Cell length less than lOOu . . 83 Lateral margins concave in some part 84 Lateral margins straight or convex . (93) 93 plicatum 84. Basal angles rounded and slight- ly protruding, apices broadly rounded . . . . . . . . . . . (91) g, quadratum 84. Basal angles rounded, but not protruding, apices angularly rounded . . . . . . .(94)C . plicatum var.'Hibernicum Semicells hexagonal-elliptic (in- , eluding base as one side) . . . . 86 Semicells not hexagonal-elliptic, but polygonal . . . . . . . . 98 86. Semicells with one or three sharp lateral median proJec- 8 tions in vertical view . . 7 86. Semicells without sharp pro- Jections in vertical view . . 9O Semicell with 2 or 3 sharp proJec- ”8 tions in vertical view . . . . . o Semicell with a single lateral pro- 89 Jection in vertical view . . . . . 88. Cell minute, 7-12u long . . . . (99) g, pygameum 88. Cell larger, more than 20u long (95) g, angulare . Low :A w J/ pq/ .. I 89. 91. 91. 93. 93- 95. 97. 97. 188 Lower lateral margins convex, lat- eral angle broadly rounded . . . . (cf. (98) g. bireme) (100) g, geometricum var. suecium Lower lateral margins retuse, lat- eral angle slightly produced . . . (97) g, pbdygonum 90. Cell more than 28u long . . . . 95 90. Cell less than 28u long . . . . 91 Lateral walls thickened in vertical view . . . . . . . . . . . . . . . (111) 93 pseudoprotu- berans Lateral walls not thickened in verti- cal view . . . . . . . . . . . . . 92 92. Sinus very shallow . . . . . . (of. (128) g, Regnesii var. tritum) (102) _c_. Sphagnicolum fa. 92. Sinus deep . . . . . . . . . . 93 Sinus gradually and regularly opened (101) g, subcapitulum Sinus linear . . . . . . . . . . . . 94 94. Cells as wide as long, or wider than long . . . . . . . . . . (103) Q, abbreviatum 94. Cells longer than wide . . . . (of. (123) g, repandum var. minor) (107) C. sexangulare fa. minima Lateral walls thickened in vertical view . . . . . . . . . . . . . . . 97 Lateral walls not thickened in verti- cal view . . . . . . . . . . . . . 96 96. Lower lateral margin sharply con- vergent towards the isthmus . (106) g, sexangulare 96. Lower lateral margin not at all or.very slightly convergent towards the isthmus . . . . . (108) g, rectangulare Poles broadly rounded in vertical view . . . . . . . . . . . . . . . (110) Q, refringens Poles acutely rounded in vertical View 0 o o o a o o o o o o o o o o (111) C 0 pSGUGOPPO- tuberans K.‘ J \L} g ’3 w U ‘a. \ .I' v v1 100 ff v}. C!) 99- 99- 101. 101. 105. 105. 107. 107. 98- Semicells with 6-8 equal mar- ginal undulations . . . . . . (58) g, impressulum 98. Semicells without 6-8 equal marginal undulations . . . . 99 Semicells with two subapical tumors. (112) g, Moerlianum var. brasiliense Semicells otherwise . . . . . . . 100 100. Semicells rhomboidal with con- cave lateral margins in ver- tical view . . . . . . . . . (114) g, clgpsydra 100. Semicells not rhomboidal with concave lateral margins in vertical view . . . . . . . . 101 Semicells longer than wide or as long as wide . . . . . . . . . . . 102 Semicells wider than long . . . . . 106 102. Cell length 28u or more . . . . 103 102. Cell length less than 28u . . . 104 Semicells rounded-polygonal . . . . (124) 9, 12212 Semicells subrectangular with ele- vated apex . . . . . . . . . . . . (115) g. difficile 104. Upper lateral margin straight . 105 104. Upper lateral margin retuse . . (118) g, meneghini Apical margin flat . . . . . . . . . (119) C. angulosum Apical margin retuse . . . . . . . . 106 106. Lateral margins convex . . . . (124) 93 laeve 106. Lateral margins retuse . . . . (125) C. quadratulum Apical margin flat . . . . . . . . . (121) C. Regnelli var. mIfiimum Apical margin retuse . . . . . . . . 108 108. Lateral margin convex . . . . . (124) g, laeve 108. Lateral margin angular . . . . 109 190 109. A sharp indentation present just above the lower lateral margin . . (127) g;_quadratulum var. applanatum not 109. A sharp indentation‘present above the lower lateral margin . . . . . (125) g. laeve var. octangularis 1. Cosmarium obsoletum (Hantzsch) Reinsch West and West, 1905. Monogr. Brit. Desm. 2:133. P1. 56, Figs. 1-3. The semicircular to subsemicircular semicells of this Species has thickened and submammillate basal angles. The vertical view is elliptic and the cell wall is punc- tulate or finely scrobiculate. The semicells are much more depressed, the width is usually greater, and the ver- tical view is more tumid than C, taxichondrum var. nudum. Measurements: L. 3#-46u; w. 42-5#u; I. 15.5-20u. Distribution: NLP, Cheboygan (T_ft 1939). 2. Cosmarium cyclicum Lund. West and West, 1905. Monogr. Brit. Desm. 2:145. P1. 58, Figs. 8, 9. The semicircular semicells of this species are reg- ularly undulate-crenate. The two or three intramarginal rows of small undulations easily distinguishes this species from g, undulatum. There is also a superficial resemblance to g, obtusatum which has truncate-pyramidate semicells. Measurements: L. #9-52u; W. 52-58u; I. 17-27.5u. Distribution: SLP, Washtenaw (Johnson 189u); NLP, Emmet (Transeau 1917). 191 3. var. Nordstedtianum (Reinsch) West and West P1. 15, Fig. l. West and West, 1905. Monogr. Brit. Desm. 2:146. P1. 58, Fig. 12. This variety has cells which are distinctly hexagonal and which have truncate apices that are less crenate than the lateral margins. Measurements: L. 48-50-(53)u; w. (53)-54-66u; I. 19-(19)- 2lu. Distribution: NLP, Crawford, New record for Michigan. 4. Cosmarium undulatum Corda West and west, 1905. Monogr. Brit. Desm. 2:148. P1. 59, Figs. 1, 2, 3, 5. The subsemicircular (at least the greater upper part) semicells with 10-12 marginal undulations (counting apical and basal angles) are characteristic of this species. C, impressulum has more pyramidate semicells which have only eight marginal undulations. This latter species is also much larger. Measurements: L. 54-64u; w. 39~52u; I. 12.5-17u. Distribution: SLP, Ionia, Jackson, Lapeer, Muskegon, Livingston, Monroe, Muskegon; EUP, Chippewa, Luce; WUP, Baraga. All records by'N & A (1932). 5. var. crenulatum (Naeg.) Wittr. West and.West, 1905. Monogr. Brit. Desm. 2:150. P1. 59, Figs. ll, 12. This variety is smaller than the typical. The semi- cells are semicircular—quadrate, and have only eight mar- 192 ginal undulations. It resembles g. impressulum very closely, but the lower lateral margins which are con- vergent towards the base and the shape of the semicells easily distinguish it from this species. Specimens from Calhoun and Gogebic Counties agree more favorably with typical measurements of var. minutum Wittr. but have the eight marginal undulations of var. crenulatum. Measurements: L. (21.8)-29-30u; w. (17)-22.5-23u; I. (6)~7—8.5u. Distribution: SLP, Calhoun; NLP, Cheboygan, Emmet (N & A 1932); WUP, Gogebic, also Baraga (N & A 1932). 6. var. minutum. Wittr. West and West, 1905. Monogr. Brit. Desm. 2:149. P1. 59, Figs. 6, 7. This variety is distinguished from the typical by the smaller size. The margin has 12-14 undulations. (See discussion on var. crenulatum for similar small forms). Measurements: L. 21-28u; w. 18-21u; I. 8.5-10u. Distribution: NLP, Cheboygan; EUP, Chippewa; WUP, Houghton. All records by N a A (1932)~l 7. var. Wollei West West and West, 1905. Monogr. Brit. Desm. 2:150. P1. 59, Figs. 8-10. This variety is intermediate in size between the typical and var. crenulatum, and the semicell margins have thirteen or fourteen crenations. Measurements: L. 32-43u; W. 27-36u; I. 10-13.5u. ’7.) rn 193 Distribution: SLP, Ionia; EUP, Delta; WUP, Houghton. All records by N & A 1932. 8. Cosmarium ocellatum Eichl. and Gutw. fa. P1. 15, Fig. 2. West and West, 1905. Monogr. Brit. Desm. 5:144. P1. 58, Fig. 6. Typically g. ocellatum has subsemicircular-pyramidate semicells with a large central scrobiculation. The var- iety incrassatum West and West has a more pyrfimidate semicell in which a ring of 2-5 lesser scrobiculations surround a large scrobiculation in a central thickened area. The variety rotundatum Fritsch and Rich has a widely Open linear sinus, a more depressed semicell than the typical, but a similar single central scrobiculation. A few specimens from Barry County do not agree perfectly with either the typical or the variety. The semicell shape (although more angular) and the sinus, are close to var. rotundatum, but the central scrobiculation is ir- regularly surrounded by two or three smaller scrobicula- tions similar to that in the var. incrassatum, although the central region was not thickened as in this latter variety. Eichler and Gutwinski's original illustrations show a variability of the semicell shape and the degree of the sinus Opening, and thus the Michigan specimens are assigned here as a form of the typical. Measurements: L. 20-(28)-30u; W. 17-(23yfi3u; I. 4-(4.3)-6u Distribution: SLP, Barry. New record for Michigan. 194 9. Cosmarium perforatum Lund. West and West, 1905. Monogr. Brit. Desm. 2:143. P1. 58, Figs. 4, 5. The subpyramidate-semicircu1ar semicells of this species have the central region of the cell wall ornamented with about twenty scrobiculations. The more angular basal angles and the open sinuses distinguish this species from g. Lundellii var. corruptum (Turn.) West and West. The numerous central scrobiculations separate it from g, EEEEf dggge Irenee-Marie. Measurements: L. 60-(6l)-75u; W. (55)-57-63u; I. 26-(32)- 36u. Distribution: SLP, Barry; WUP, Houghton; Isle Royale (Prescott 1938). 10. Cosmarium pachydermum Lund. West and West, 1905. Monogr. Brit. Desm. 2:139. P1. 57, Fig. 7. The subsemicircular shape of the semicells and the very thick walls are distinctive features of this species. The vertical view is broadly elliptic, and the cell wall is densely punctate. It resembles g, tuddalense Strom, which has numerous definite pores in the cell wall, and a narrower isthmus. Measurements: L. 78-117u; W. 60-87u; I. 29-40u. Distribution: SLP, Barry (2), Livingston; NLP, Cheboygan (N a A 1932, Welch 1938a); EUP, Alger, Schoolcraft, also Schoolcraft (Transeau 1917); Isle Royale (Prescott 1937, 1938). ll. 12. C05 .fi. e F1 FD. In. 195 11. Cosmarium Ralfsii Breb. West and West, 1905. Monogr. Brit. Des. 2:141. P1. 57, Fig. 10; P1. 58, Figs. 1, 2. This species has subpyramidate-semicircular semicells. The vertical view is rhomboid-elliptic, and the cell wall is finely punctate or scrobiculate. It resembles C, Lun- dellii, from which it can be distinguished by the usually larger size, the more narrow isthmus, and the parietal chloroplasts. Measurements: L. 112-120u; W. 95-104u; I. 21-25u. Distribution: SLP, Wayne (Campbell 1886). 12. var. nethiopicum West and West West and West, 1905. Monogr. Brit. Desm. 2:140. P1. 57, Figs. 8, 9. This variety is separated from the typical by the thinner cell wall, The cell wall also is scrobiculate with minute punctations between the scrobiculations. Measurements: L. 69-(81)-(96)-107u; W. 61-(66)-(77)—80u; I. 28-(32)-33-34u. Distribution: SLP, Ingham, Clinton; NLP, Cheboygan (N & A 1932); EUP, Delta, Alger; WUP, Menominee. 13. Cosmarium circulare Reinsch West and West, 1905. Monogr. Brit. Desm. 2:136. P1. 56, Figs. ll, 13, 14. The semicircular semicells of this species have rounded basal angles. The vertical view is narrowly e1- 196 liptic and the cell wall is punctulate. The semicircular front view and the narrowly elliptic vertical view sep— arate this species from g. Lundellii. Measurements: L. 47-(47)-95u; W. 46-(46)-90u; I. (13)-' l4-28u. Distribution: SLP, Barry, Washtenaw; NLP, Cheboygan (Welch 1938a); EUP, Mackinac; WUP, Gogebic, also Houghton (N a A 1932). 14. Cosmarium Lundellii var. ellipticum West West and West, 1905. Monogr. Brit. Desm. 2:138. P1. 57, Figs. 3, 4. This organism has pyramidate-semicircular semicells. The vertical view is elliptic and the cell wall is punc— tate. It has a superficial resemblance to g, capense De Toni, but the deeper constriction and large size easily‘ distinguish it. Measurements: L. 68-73u; W. 53-55u; I. 16-2lu. Distribution: SLP, Ottawa (N a A 1932). 15. Cosmarium canadense Irenée-Marie P1. 15, Fig. 6. Irenee-Marie, 1938. Flor. Desm. de la Reg. Mont. :164. P1. 32, Figs. 3, 4. This species resembles some expressions of g, 222? foratum Lund.except for the leak of scrobiculations in the central region of the semicell wall. The semicells are subsemicircular-pyramidate, and the sinus is short and open. The vertical view is more broadly elliptic 197 than the above species, and the punctate semicell wall is slightly thickened in the central region. ieasurements: L. 59-65-(69)-(71)u; W. 58—61-(62)-(67)u; 1- (31)-35-37u- Distribution: SLP, Washtenaw, Barry; EUP, Alger; WUP, Marquette. New records for Michigan. 16. Cosmarium tuddalense Strom Strom, 1919. Nyt. Mag. f. Natur. 57:29. P1. 4, Fig. 8. The semicells of this species are transversely (rarely sub-semicircular-pyramidate) semi-elliptic in front view, and elliptic in vertical view. The very thick semicell walls have numerous pores. There is a gen- eral resemblance to g, pachyderlum Lund., but the distinct pores in the semicell walls and the usually greater size, as well as the smaller isthmus distinguish it from this species. Measurements: L. 94-(95)-l50u; W. 65-(70)~101u; I. 15- (22)-28u. Distribution: EUP, Delta; WUP, Marquette; Isle Royale (Prescott 1938). 17- ‘ggsmarium subundulatum Wille West and West, 1905. Monogr. Brit. Desm. 2:151. P1. 59, Figs. 13, 15. The semi-elliptic semicells of this species have mar— gins that are twelve undulate. In addition, there are two intramarginal rows of undulations. The vertical view 198 is elliptic with broad lateral protuberances. The semi- cell wall is punctate and sometimes has several scrobicu- lations near the margins. The semi-elliptic shape of the semicells and the central protuberance distinguish this species from g, undulatum Corda. Measurements: L. 45-60u; W. 32-39u; I. 15-16u. Distribution: Isle Royale (Prescott 1938). 18. Cosmarium subcucumis Schmidle West and West, 1905. Monogr. Brit. Desm. 2:155. P1. 60, Figs. 1-3. This Species has semi-elliptic (withlong axis verti cal) semicells in front view which are broadly elliptic in transverse view. The sinus is linear, closed or Open at the base. The semicell wall is finely punctate. The two pyrenoids in each semicell separates this species from Q, cucumis (Corda) Ralfs. Measurements: L. 60 (60)-(64)-87u; w. 36-(39)-(42)-54u; I. 14-(19)-19—21u. Distribution: SLP, Calhoun, Ingham, Livingston, Washtenaw; NLP, Crawford, Roscommon, also Emmet (N a A 1932); WUP, Gogebic, also Marquette (Pres. and Mag. 1935). 19- Cosmarium cucumis (Corda) Ralfs. P1. 15, Fig. 3- West and West, 1950. Monogr. Brit. Desm. 2:152. P1. 59, Figs. 18—20. The semicells of this species are semi-elliptic (long axis vertical) in front view, and broadly elliptic or el- 199 liptic-Oblong in vertical view. The cell wall is smooth. The parietal band-shaped chloroplasts, each with several pyrenoids distinguish this species from g, subcucumis Schmidle. Measurements: L. (54)-59-102u; W. (30)-34-56u; I. 15-(17)— 38u. Distribution: SLP, Barry; EUP, Sahoolcraft (2); WUP, Houghton, Gogebic. New records for Michigan. 20. Cosmarium moniliforme (Turp.) Ralfs. West and West, 1908. Monogr. Brit. Desm. 3:20. P1. 67, Figs. 1-3. This species has cells constricted by a deep, widely Open sinus into two circular or subcircular smooth walled semicells. The vertical view is circular. Measurements: L. 21-37u; W. 11-23u; I. 3-9u. Distribution: NLP, Cheboygan (N a A 1932)- 21. fa. pgnctata Lagerh. P1. 15, Fig. West and West, 1908. Monogr. Brit. Desm. 3:22. P1. 67, Fig. 4. This form is separated from the typical by the punc- tate semicell wall which sometimes becomes yellow. Measurements: 24-(42)-43u; W. l4-(2l)-25u; I. 3.5-(6)-6.5u. Distribution: NLP, Emmet. New record for Michigan. 22. fa. panduriformis Heimerl. P1. 15, Fig. 5. West and West, 1908. Monogr. Brit. Desm. 3:22. P1. 67, Figs. 8, 9. 200 This form is distinguished from the typical by a pro- portionately broader isthmus and an obtusely rounded sinus. Measurements: L. l7-(25)-27u; w. lO-(15)-l5u; I. 6-(9)- 16u. Distribution: SLP, Barry. New record for Michigan. 23. fa. elongata West and West P1. 15, Fig. 8. q West and West, 1908. Monogr. Brit. Desm. 3:23. P1. 75, Fig. 10. The semicells Of this form are broadly elliptic. (Vertical axis the long axis). Measurements: L. (35)-38-42-(43)u; W. 17-(17)-(18)-20u; I~ 4-(5)-(7)-7u. Distribution: SLP, Barry; NLP, Emmet; EUP, Schoolcraft. New records for Michigan. 24. var. subpyriforme West and West P1. 15, Fig. 7. West and West, 1908. Monogr. Brit. Desm. 3:23. P1. 67, Fig. 5. This variety has angularly abovate semicells. The apices and lower lateral margins may be slightly flattened. Measurements: L. 40—(43)u; W. 20-(23)u; I. (7.5)-7.7u. Distribution: EUP, Delta. New record for Michigan. 25. ggsmarium diplospora (Lund.) Luetk. West and West, 1904. Monogr. Brit. Desm. 1:61. Pl. IV, Figs. 40, 41. This species has moderately large subcylindrical cells that have a very slight constriction. The cell wall which 201 is slightly thickened at the apex, is smooth. Each semi- cell has a central pyrenoid and a chloroplast with num- erous radiating processes. The zygospore is double. Measurements: L. 32.5-66-(70)u; w. 22.5-53-(36)u. Distribution: NLP, Roscommon; EUP, Delta; Isle Royale (Prescott 1937). 26.; var. £3122. West West and West, 1904. Monogr. Brit. Desm. 1:61. P1. 4. Figs. 42, 43. This variety is almost twice the size Of the typicd‘ and may lack a constriction at times. Measurements: L. lO2-l21u; W. 48-54u. Distribution: Isle Royale (Prescott 1937). 9?. Cosmarium subtile (West and West) Luetk. West and West, 1904. Monogr. Brit. Desm. 1:92. P1. 8, Figs. 27-29. The small subcylindrical cells of this species have a slight, almost imperceptible median constriction. The cell wall is sparsely and indistinctly punctate according to West and West (1904) but Borge (1936) illustrates and describes Swedish specimens in which the "porenapparate" firotrudes slightly on the lateral margins, perhaps indi- cating that the punctulations Of West and West are really pores. The "porenapparate" referred to above may have been mucilage threads. Measurements: L. 14-15.7u; W. lO-ll.4u. Distribution: NLP, Cheboygan (N a A 1932). 202 28. Cosmarium cucurbita Breb. West and West, 1908. Monogr. Brit. Desm. 3:106. P1. 73, Figs. 31—33; P1. 74, Fig. 3. The subcylindrical-subquadrate semicells of this species have a very slight median constriction. The lat- eral margins are subparallel and the apices are convex or c0nvex~truncate. The vertical view is circular, and the cell wall is punctate. This species appears tO be very similar to g, cucurbitinum (Biss.) Luetken, from which it can be separated by the smaller size and the less atten- uated lateral margins. The writer does not feel that fa. minutum Of g, cucurbitinum can be separated distinctly from this species and so it is included here.' Measurements: L. 25—(34)-(38)-40-51u; W. l2-(l5)-(l7)- (19)-2SU- Distribution: SLP, Ingham, Livingston, Oakland, Berrien; NLP, Cheboygan, also Cheboygan (N & A 1932); EUP, Chippewa, Delta, Schoolcraft; WUP, Gogebic (3), Houghton, Baraga, also Marquette (Pres. and Mag. 1935). 29. Cosmarium cucurbitinum fa. min23_ (West and West) Luetk. West and West, 1904. Monogr. Brit. Desm. 1:94. P1. 9, Figs. 13, 14. Typically 23 cucurbitinum fa. mingg has subcylindrical cells with a very slight median constriction. The cell wall is minutely punctate. This species has a great simi- larity to some expression Of’Qx cucurbita, but has more. attenuated lateral margins, more broadly rounded apices and a smaller size. 203 Measurements: L. 50-58u; W. 22-25u. Distribution: NLP, Cheboygan (N & A 1932, Taft 1939). 30. Cosmarium elongatum Racib. fa. Borge. Borge, 1923. Arkiv. f. Bot. K. Sv. Vets. Akad. 18(10): 8. P1. 1, Fig. 4. This large species has subcylindrical cells with a slight but very distinct constriction. The lateral mar- gins are slightly convex and taper gradually to rounded or convex-truncate apices. The wall is punctate. Speci- mens from Chippewa County resembled very closely the or— ganism illustrated and identified by Whelden (1943) as c_. subturgidum (Turn.) Schmidle fa. They were also simi- lar to specimens of g, Clevei (Lund) Luetk. shown by Irenee Marie (1949). In all cases, the apical region was coarsely punctate or scrobiculate. According to West and West (1904), C, Clevei has small granules in the apical region. Consequently, the Michigan specimens are assigned questionably t0 Borge's form of g. elongatum which does not have pronounced punctations in the apical region. The figure Of Cosmarium (Penium) cucurbitinum fa. maQus West and West, reported by Prescott and Magnotta (1935), from Marquette County, should probably also be placed here. Measurements: L. 94-106-(129)u; W- 36-(38)-39u; I. 31.5—(36)-36u. Distribution: EUP, Chippewa; WUP, Marquette (Pres. & Mag. 1935); Isle Royale (Prescott 1938). 204 31. Cosmarium subarctoum (Lagerh.) Racib. West and West, 1908. Monogr. Brit. Desm. 3:31. P1. 68, Figs. 6-8. - This small species has transversely subelliptic semi- cells. The sinus is open and subacute at the apex. The convex apex is slightly flattened. The vertical view is elliptic. It can be separated from g. subarctoum by the smaller size and the more elliptic semicells, and from g. subtile and Q. globosum by the elliptic shape in ver— tical view. Measurements: L. 15—(21.5ux w. l2-l7u; I. 8.5-11.5u. Distribution: NLP, Cheboygan (N a A 1932, Welch 1936b). 32. Cosmarium globosum Bulnh. West and West, 1908. Monogr. Brit. Desm. 3:29. Pl. 168, Figs. 1, 2. The semicells of this small species are subcircular. The sinus is widely Open and has a subacute apex. The vertical view is circular and the cell wall is punctate. Measurements: L. 30-36u; W. 22-25u; I. 17—l9u. Distribution: NLP, Cheboygan (N a A 1932, Welch 1938a). 33. fa. min9£_ Boldt. West and West, 1908. Monogr. Brit. Desm. 3:30. This form is similar to the typical in cell shape but is smaller. Measurements: L. 16.8-24u; W. l2~15u; I. 10.8-12u. Distribution: SLP, Oakland; NLP, Cheboygan (Taft 1939). V8? «8 P] 205 34. var. W01 ei West and West West and West, 1896. Trans. Linn. Soc. Bot. 5(5):252. P1. 15, Fig. 17. This variety has a slighter constriction, a more semi~elliptic—shaped semicell and is slightly larger than typical. Measurements: L. 38.5u; W. 24u; I. 21u. Distribution: NLP, Cheboygan (N & A 1932, Welch 1938a). 35- Cosmarium pseudoconnatum Nordst. West and West, West, G. S. 1908. Monogr. Brit. Desm. 3:27. P1. 67, Figs. 19-21. The semicells of this species are semi-elliptic (subcircular for about 2/3 Of the margin). The constric- tion is slight and the sinus is broad and very shallow. The vertical view is circular or subcircular and the cell wall is punctate. This species can be separated from Q, connatum Breb. by the smaller size, the non-scrobicu- late cell wall, and the smaller constriction. Some spec- imens from Gogebic County are much smaller than typically. Measurements: L. (40)-47-57-5-59u3 W: (29)-33-(43.5)-45u; I. (26)-30-(38)—41. Distribution: SLP, Barry (2), Calhoun, Livingston; NLP, Emmet, also Cheboygan (Taft 1939); WUP, Gogebic. 36. ggsmarium connatum Breb. West and West, 1908. Monogr. Brit. Desm. 3:25. P1. 67, Figs. 15-17. 206 The semicells of this species are transversely sub- elliptic (circular for about 2/3 of margin). The constric- tion is very slight, the sinus being widely open and with an obtuse apex. The vertical view is subcircular and the cell wall is scrobiculate with fine punctations between the scrobiculations. This species is larger, has a more pronounced constriction and less rounded semicells than 2, pseudoconnatum, Measurements: L. 65-(79)-lOOu; W. 46-(58)-74u; I. 40-(41)— 54u. Distribution: SLP, Barry (2) also Ionia (Wade 1949) and Macomb (Pieters 1894); NLP, Presque Isle, also Cheboygan (N & A 1932); EUP, Delta; WUP, Marquette; Isle Royale (Prescott 1937, 1938). 37. Cosmarium alpestre Roy and Biss. West and West, 1908. Monogr. Brit. Desm. 3:24. P1. 67, Fig. 14. The semicells of this species are subsemicircular. The constriction is very slight and the isthmus is broad. The vertical view is broadly elliptic and the cell wall is thickly and finely punctate, the punctae along the isthmus being larger. The very slight constriction dis- tinguishes this Species from.g, connatum Breb. Measurements: L. 78-105u; W. 58-90u. Distribution: Isle Royale (Prescott 1938). 38- ggsmarium inconspicuum. West and West West and West, 1905. Monogr. Brit. Desm. 2:164. P1. 61, Figs. 1, 2. ' 207 The transversely elliptic semicells of this species have broadly convex apices. The sinus is open and sub- rectangular. The vertical view is elliptic and the cell wall is smooth. It resembles g, subarctoum (Lagerh.) Racib. but the smaller size, the convex apices and the broader sinus clearly differentiates it from this species. Measurements: L. 13.5-1#.6u; W. 9.5—12u; I. n.8-6.5u. Distribution: EUP, Schoolcraft; WUP, Houghton. Both ro- cords by Nichols and Ackley (1932). 39. Cosmarium depressum var. achondrum (Boldt) West and West P1. 15, Fig. 9. West and West, 1905. Monogr. Brit. Desm. 2:177. P1. 62, Figs. 6—9. The semicells of this organism are subhexagonal—el- liptic. The apices are flat and the sinus is linear but opens outwardly. The vertical view is elliptic and the cell wall is finely punctulate. Measurements: L. 37-(38)-51u; w. 40-(40)-51u; I. (10.5)— 12-l7u. Distribution: NLP, Presque Isle; EUP, Alger, Mackinac; WUP, Marquette. New records for Michigan. 40. Cosmarium depressum var. reniforme West and West West and West, 1905. Monogr. Brit. Desm. 2:178. P1. 62, Fig. 10. This organism has narrowly elliptic-reniform semi- cells. The sinus is open and the cell wall is smooth. The vertical view is elliptic. It can be distinguished from Q: subdepressum by the open sinus and the smooth cell wall. Measurements: L. 2lug W. 26u; I. 6.5u. Distribution: Cheboygan (Taft 1939). 41. Cosmarium subdepressum West and West P1. 16, Fig. l. West and West, 1896. Trans. Linn. Soc. of Lon. Bot., 25(5):247. P1. 15, Fig. 15. This Species has narrowly elliptic—reniform semicells which are finely granulate-punctate. The constriction is deep, the sinus being linear and slightly closed in some part. The vertical view is elliptical. The Michigan Specimens were somewhat larger than typical. Measurements: L. 15—(22)u; W. 21-(26)u; I. (3.5)-3.7u. Distribution: SLP, Oakland. New record for Michigan. #2. Cosmarium phaseolus fa. mingg. Boldt. P1. 16, Fig. 2. West and West, 1905. Monogr. Brit. Desm. 2:159. P1. 60, Fig. 15. The semicells of this organism are hexagonal elliptic. The constriction is deep and the sinus narrow and is opened outwardly. The vertical view is elliptic with a small pro- tuberance on each lateral margin. The cell wall is min- utely punctate. The central protuberance on each semi- cell separates this from.g, subtumidum.Nordst. Measurements: L. (20.4)-2lu; W. 18-(2l.5)u; I. (4.5)- 5 05‘6uo Distribution: WUP, Gogebic. New record for Michigan. 209 43. Cosmarium phaseolus var. elevatum. Nordst. P1. 16, Fig. 3. West and West, 1905. Monogr. Brit. Desm. 2:159. P1. 60, Figs. 16, 17. This variety has hexagonal-elliptic semicells with} truncate~convex apices. Specimens from Houghton and Barry Counties are somewhat intermediate between this variety and var. rectangulare Insam and Krieger (1936). The latter has more subrectangular semicells. Measurements: L. (25)-25.5-28.8u; W. (21.5)-23.5-30u; ' I. (5)-7-(8)-10u.. Distribution: SLP, Barry; WUP, Houghton. New record for Michigan. 44. Cosmarium tumidum Lund. West and West, 1905. Monogr. Brit. Desm. 2:160. P1. 60, Fig. 18. The subsemicircular—elliptic semicells of this species have broadly convex apices. The constriction is deep and the sinus is narrow but open outwardly. The vertical view is elliptic with strong tumid lateral margins. The cell walls are punctate, the punctations often much larger and distinct in the central region of the semicells. Measurements: L. (28)-(30)-31-(32)-37u; W. (22)-93-(24)‘ (26)-32u; I. 6-(6)-(8)—9.5u. Distribution: SLP, Barry, Calhoun, Oakland; NLP, Emmet, also Emmet (N a A 1932); EUP, Chippewa; WUP, Gogebic. 210 45. Cosmarium sulcatum Nordst. Nordstedt. 1878. De. Alges aquae dulcis et de Characeis ex insulis Sandvicensibus a Sv. Berggren 1876 reportatis :13. Pl. 1, Fig. 18. This species has hexagonal elliptic semicells, with bluntly pointed lateral angles. The vertical view is elliptic with obtuse poles and with three undulations on the middle of each lateral margin. Measurements: L. 36-#2u; W. 28-34u; I. 8-lOu. Distribution: SLP, Macomb (Johnson 189i, Pieters 1894). 46. Cosmarium contractum Kirchn. West and West, 1905. Monogr. Brit. Desm. 2:170. P1. 61, Figs. 23-25, 34. The semicells of this species are subelliptic to al- most sub-semicircular in shape with the ventral margins more convex thanflfiorsal. The constriction is deep with the sinus widely open. The isthmus is narrow with parallel walls. The vertical view is elliptic and the cell wall is finely punctate. Measurements: L. 29-(40)-56u; W. 22-(22)-(25)-40u; I. 5-(6.5)-l2.5u. Distribution: SLP, Oakland, Washtenaw, also Lapeer (N & A l932)and Macomb Pieters 1894); EUP, Alger; WUP, Gogebic (2). 47. var. ellipsoideum (Elfv.) West and West West and West, 1905. Monogr. Brit. Desm. 2:172. P1. 61, Figs. 28, 35. 211 This variety is separated from the typical by the proportionately wider and the more perfect elliptic semi- cells. The cell wall is smooth. Measurements: L. 31—(34)-(38)-55u; W. 2H-(28)-(3Qb42; I. 7-(7)-15u. Distribution: SLP, Barry, Berrien, Livingston; NLP, Emmet (N & A 1932); Isle Royale (Prescott 1938). 48. Cosmarium tinctum Ralfs. West and West, 1905. Monogr. Brit. Desm. 2:168. P1. 61, Figs. 16-18. This small Species has elliptic semicells with smooth cell walls of a reddish brown color. The constriction of the cell is fairly deep, the sinus narrow but opening in the outer part. Measurements: L. 10-15u; W. 7.5-ll.6u; I. 4.5-8.4u. Distribution: NLP, Cheboygan (Taft 1939). 49. Cosmarium bioculatum Breb. West and West, 1905. Monogr. Brit. Desm. 2:165. P1. 61, Figs. 3-7. The semicells of this species are oblong-elliptic. The constriction is deep with the sinus narrowly open. The vertical view is oblong elliptic. This species has a general resemblance to g, tumidum Lund. and g, phaseolus Breb. but is smaller than the former and lacks the cen- tral protuberance of the semicells of the latter. Measurements: L. 15—(25)-30u; W. 15-(25)-30u; I. 4.3-(8)- llu. 212 Distribution: SLP, Oakland, also Wayne (Campbell 1886), and Lapeer (N a A 1932); WUP, Gogebic. 50. var. hian§_ West and West P1. 16, Fig. 4. West and West, 1905. Monogr. Brit. Desm. 2:166. P1. 61, Figs. 10, 11. This variety has a more open sinus and the apices of the semicell are straight or slightly retuse. Measurements: L. 17-(17)-19u; W. (l4)-15-l7u; I. 3.5-(4.5)u. Distribution: WUP, Gogebic. New record for Michigan. 51. Cosmarium Holmiense Lund. West and West, 1908. Monogr. Brit. Desm. 3:1. P1. 65, Figs. 1, 2. The pyramidate-truncate semicells of this species have the lateral margins (a short distance below the apex), sharply constricted giving a dilated appearance to the apices. The upper parts of the lateral margins are also characteristically undulate and the apical margins are slightly biundulate. Measurements: L. 43-66u; W. 26-40u; I. l4-2lu.‘ Distribution: Isle Royale (Prescott 1938). 52. var. integrum Lund. West and West, 1908. Monogr. Brit. Desm. 3:2. P1. 65, Figs. 3-5. This variety is separated from the typical by the convex apices and the lack of undulations in the upper lateral margins. Measurements: L. 45-(53)-(57)—62u; W. 28-(34)-40u; I. 15-(17)-22u. 213 Distribution: SLP, Calhoun, also Ionia (N a A 1932); NLP, Crawford, also Cheboygan (N a A 1932); Isle Royale (Prescott 1938). 53. Cosmarium tetragonum var. Lundellii Cooke West and West, 1908. Mongr. Brit. Desm. 3:18. P1. 66, Figs. 23, 24. The subquadrate semicells of this species havethe triundulate (including apical and basal angles) lateral margins slightly convergent towards the apex. The apices are convex and undulate. The sinus is linear and closed. The vertical view is elliptic and the cell wall is smooth. Measurements: L. 38-50u; W. 22-29u; I. 8-10u. Distribution: Isle Royale (Prescott 1938). 54. fa. Schmidlei Gutw. Schmidle, 1893. Ber. d. Deutsch. Bot. Gesell. ll:(lO):549. P1. 28, Fig. 6. This form is identical with var. Lundellii except for the presence of supraisthmial granules on each semicell. Measurements: L. 47-(47)u; W. 25.4-(28)u; I. (6.5)-7.8. Distribution: WUP, Menominee, Marquette, also Marquette (Pres. and Mag. 1935)- 55. Cosmarium obtusatum Schmidle West and West, 1908. Monogr. Brit. Desm. 3:7. P1. 65, Figs, 13, 14. The semicells are truncate-pyramidate with convex 0 lateral margins, each of which has 8-9 undulations. In 214 addition, there are several secondary rows of undulations Just within the margin. The vertical view is oblong-e1- liptic and the cell walls are punctate. Specimens from Houghton County have slightly convex apices, so that the semicells are almost semicircular. Measurements: L. (42)-44-(60)-60-64u; W. 37-(42)-(50)-52- (53)u; I. 13-(13)-(15)-(17)-18u- Distribution: SLP, Livingston, Washtenaw; also Tuscola (N & A 1932); EUP, Mackinac; WUP, Houghton. I 56. Cosmarium venustum (Breb.) Arch. West and West, 1908. Monogr. Brit. Desm. 3:8. P1. 66, Figs. 1-3. The lateral margins of the truncate-pyramidate semi- cells have a single median undulation. The basal and apical angles are rounded, and the apical margin is slightly retuse. The vertical view is elliptic and the cell wall is finely punctate. A single specimen from Chippewa County had the lateral undulations greatly reduced and the wall coarsely punctate. Measurements: L. 24-(30)-(32)-43u; W. 18-(22)-32.5u; I. (5)-5.5-13.4u. Distribution: NLP, Roscommon, also Emmet (N & A 1932); EUP, Chippewa; Isle Royale (Prescott 1938). 57. var. excavatum fa. duplo-magor Gutw. Gronblad, 1921, Acta. Soc. pro. Faun. et Flor. Fenn. 49:37. Pl. 7, Figs. 18-19. C') h.” JV 0 215 This forma is separated from the typical Cosmarium venustrum (Breb.) Archer by the presence of a central scrobiculation in each semicell. Scrobiculations in specimens from Emmet County were excentrically placed. Measurements: L. 36-(36)-41.5u; W. 25-(25)-27.5u; I. 4.5-(4.5)-5.8u. Distribution: NLP, Emmet; Isle Royale (Prescott 1937, 7 1938). 58. Cosmarium impressulum Elfv. West and West, 1908. Monogr. Brit. Desm. 3:86. P1. 72, Figs. 14-18. This species has semi-elliptic or subcircular (vaguely polygonal) semicells in which each lateral margin possesses four undulations (including apical and basal angles). This characteristic and the different cell shape distingu- ish this species from 9: undulatum Corda. The rectangular basal angles differentiates it from g, undulatum.var. crenulatum (Naeg.) Wittr. Measurements: L. 20-(26)-(36)-36-(43)u3 W: 14-5-(19-5)- (21)-(26)-26u; I. 3.5-(5)-(6)-(9)u- Distribution: SLP, Barry (2), Calhoun, Shiawassee, Clin- ton, Jackson, Oakland, also Macomb (Johnson 1894 Pieters 1894) and Lapeer (N a A 1932); NLP, Presque Isle also Cheboygan, Emmet (N & A 1932); EUP, Alger, Mackniac, Schoolcraft; WUP, Marquette, Gogebic (2). 59. fa. suborthogonum (Racib.) West and West Taylor, 1934. Pap. Mich. Acad. Sci. Arts and Letters. 19:255. P1. 58, Fig. 20. 216 This organism differs only from the typical in the presence of a slight protuberance in the center of each lateral margin in vertical view. Measurements: L. 25-28-(30)u; W. l9-(2l)-22u; I. 6u. Distribution: SLP, Washtenaw; Isle Royale (Prescott 1938). 60. Cosmarium trilobulatum Reinsch West and West, 1905. Monogr. Brit. Desm. 2:185. P1. 62, Figs. 28-30. This species has semicells that are tri-lobed. The lateral margins between the basal lobes and the apical ' lobe are concave. The apices are straight or slightly convex. The vertical view is elliptic and the cell wall is smooth. Measurements: L. 20-23u; W. l3-20u; I. 3.8-4.4u. Distribution: Isle Royale (Prescott 1938). 61. var. basichondrum Nordst. P1. 16, Fig. 5. Nordgfé 1888. Kongl. Sv. Vet. Akad. Handl. 22(8):57. Pl. 6, Fig. 11. This variety can be distinguished from the typical by the triundulate lateral margins (including apical and basal angles) and by the supraisthmial papilla at the base of each semicell. The Michigan specimens resemble (in shape) var. mgigg Taylor (1934) which is different from var. basichondrum only in the larger size. Measurements: L. 26-31-(32)u; W. l7-2l-(22)—(23)u; I. (4.5)-6-7u. 217 Distribution: SLP, Barry; EUP, Alger, New records for Michigan. 62. fa. retusa Reinsch P1. 16, Fig. 8. Insam and Krieger, 1936. Hedwigia, 76:110. P1. 3, Fig. 19. This variety has a small pore in the central region of each semicell. This form should be compared with g. subreinschii var. ocellatum.West and West from which it can be separated by the slightly divergent lower lateral margin and the lack of an undulation on the upper lateral margin. Measurements: L. l9-(21.8)u; W. l3.3-(15)u; I. (3)-4.2u Distribution: NLP, Crawford. New record for Michigan. 63. Cosmarium subreinschii var. ocellatum_ West and West West, W. and West, C. S. 1902. Trans. Linn. Soc. Bot., 2nd Ser., 6:165. P1. 20, Fig. 33. This species has truncate-pyramidate Semicells. The lateral margins are triundulate (including basal and api- cal angles). The central region of the semicell wall is ornamented with a large scrobiculation, the rest of the semicell wall being punctate. The vertical new is elliptic With central protuberance on each lateral margin. Measurements: L. 26-28.5u; W. l7-l9u; I. 4-5u. 64. Cosmarium Hammeri Reinsch West and West, 1905. Monogr. Brit. Desm. 2:181. P1. 62,, Figs. 20, 21. This species has truncate-pyramidate semicells in which the basal angles are broadly rounded and the upper 218 lateral margins and the apical margins are slightly con- cave. The vertical view is elliptic and the cell wall is smooth. Measurements: L. 40-50u; W. 27-35u; I. ll-l3u. Distribution: NLP, Cheboygan (N & A 1932, Welch 1938a). 65. var. protuberans West and West West and West, 1905. Monogr. Brit. Desm. 2:183. P1. 62, Figs. 24, 25. This variety is smaller than the typical and in vertical view has an inflation of the lateral margins. Measurements: L. 24-35u; W. 18.5-21.5u; I. 7-7.5u. Distribution: SLP, Calhoun (Pres. and Mag. 1935). 66. Cosmarium retusiforme (Wille) Gutw. West and West, 1905. Monogr. Brit. Desm. 2:180. P1. 62, Fig. 19. The semicells of this species are truncate-pyramidate. The basal angles are broadly rounded, the upper lateral margins slightly retuse and the apices straight and sharply truncate. The vertical view is elliptic, with lateral margins inflated in the median region. This species can be separated frbm.§, retusum (Qerty) Rabh. by the lack of granules on the semicell wall and from.g, Hammeri Reinsch by the smaller size and the sharper apical angles. Measurements: L. 22.5-24u; W. 19-19.5u; I. 6-7u. - Distribution: SLP, Macomb (West and West 1898). 67. ggsmarium pokornyanum.(Grun.) West and West P1. 16, Fig.6. West and West, 1905. Monogr. Brit. Desm. 2:190. P11 63, Figs 0 11-15 0 219 Characteristics of this species are the somewhat trilobed or truncate-pyramidate semicells. The basal angles are rectangular and slightly retuse. The upper lateral margins are strongly convergent and concave and the apical lobe is narrowly truncate and slightly retuse in the median region. The vertical view is rhomboid- elliptic and the cell wall is smooth. Measurements: L. 23-(25)-39u; w. l4-(l7)-22u; I. (5)- 6.5-llu. Distribution: EUP, Delta; WUP, Menominee. New records for Michigan. 68. Cosmarium granatum Breb. West and West, 1905. Monogr. Brit. Desm. 2:186. P1. 63, Figs. 1-3. The truncate-pyramidate semicells of this species have rectangular basal angles. The upper lateral margins are straight or slightly convex and converge sharply to the narrowly truncate apex. The vertical view is elliptic and the cell wall is finely punctate. Some of the speci- mens from Calhoun County have distinctly inflated semicells in which the lateral margins are distinctly convex and the apex is not as clearly truncate as typically. Measurements: L. 26-(38)-(43)-h7u; w. 19-(28)—(3o)-3o- (32)u; I. 3.8-4.4—(7.5). Distribution: SLP, Calhoun (2), Barry (2), Washtenaw, Jackson, also Lapeer, Livingston (N & A 1932) and Macomb 220 (pieters 1894); NLP, Cheboygan, Emmet (N & A 1932) also Cheboygan (Neal 1948); EUP, Alger, also Mackinac (N & A 1932); WUP, Marquette, Menominee. 69. var. subgranatum Nordst. ,— West and West, 1905. Monogr. Brit. Desm. 2:188. P1. 63, Figs. 5-8. This variety is separated from the typical by the different semicell shape. The lower lateral margins are slightly divergent (occasionally slightly retuse medianly) and the upper lateral margins are Sharply convergent (and 1—2 undulate) to the narrowly truncate apex. The vertical view is narrowly elliptic with the lateral margins slightly tumid. Measurements: L. 24-(29)-30u; W. 17~(2l)-22u; I. (4.5)- 6-9u. Distribution: Oakland, also Washtenaw (Johnson 1895); Isle Royale (Prescott 1938). 70. Cosmarium subtumidum Nordst. West and West, 1905. Monogr. Brit. Desm. 63, Figs. 18-20. This Species has pyramidate—semicircular semicells. The basal angles are broadly rounded, the lateral mar- gins convex and the apices broadly truncate and straight. The vertical view is elliptic and the cell wall is min- utely punctate. Measurements: L. 30-42-(44)u; W. 24-34-(39)u; I. 7.5- (10.5)-10.5u. Distribution: NLP, Roscommon, also Cheboygan, Emmet 221 (N a A 1932) and Cheboygan (Neal 1948); EUP, Schoolcraft, Alger; Isle Royale (Prescott 1938). 71. var. Klebsii (Gutw.) West and West West and West, 1905. Monogr. Brit. Desm. 2:193. P1. 63, Figs. 21-23. This variety has more broadly rounded basal angles than the typical and the lateral margins are more con- vergent with a resulting narrower apex. Measurements: L. 32-41u; W. 29-35u; I. 7-llu. Distribution: Calhoun (Pres. and Mag. 1935)._ 72. Cosmarium capense fa. minor West and West West, W. and West, G. S. 1898. Jour. Linn. Soc. Bot. 33:301. P1. 17, Fig. 3. This species has truncate, pyramidate semicells with convex lateral margins and broadly rounded basal angles. The apical margins are straight. The constriction is moderately deep with the sinuses closed inwardly. The vertical view is elliptical. Measurements: L. 64u; W. 46u; I. l6u. Distribution: SLP, Washtenaw (West and West 1893). 73. Cosmarium galeritum Nordst. P1. 16, Fig. 16. West and West, 1905. Monogr. Brit. Desm. 2:194. P1. 63, Figs. 24, 25. The pyramidate-trapeziform or truncate—pyramidate semicells of this species have rounded basal and apical angles. The lateral and apical margins are straight or slightly convex. The vertical view is elliptic and the 222 semicell wall is punctate. This species resembles Q, Lundelli var. ellipticum but is smaller and has more py- ramidate semicells. Measurements: L. (50)-5l-(60)u; W. 42-(44)-50u; I. (13:5)- 15-18u. Distribution: .NLP, Presque Isle. New record for Michigan. 74. Cosmarium pseudonitidulum Nordst. West and West, 1905. Monogr. Brit. Desm. 2:195. P1. 63, Fig. 26. The subtrapezoid or truncate-pyramidate semicells have rounded basal and apical angles. The slightly con- vex lateral margins are suberect near the basal angles and sharply convergent above to the broadly truncate and slightly convex apex. The vertical view is elliptic and- the cell wall is punctate. The smaller size separates this species from g, galeritum Nordst. and the single py- renoid in each semicell distinguishes it from g, nitidulum De Not. Measurements: L. 42-46.8u; W. 33-35u; I. lO-15.6u. Distribution: SLP Macomb (Pieters 1894); Isle Royale (Prescott 1938) . 75. var. validum West and West P1. 17, Fig. 1. West and West, 1905. Monogr. Brit. Desm. 2:196. P1. 63,‘ Figs. 27-30. This variety is larger than the typical and has less rounded basal angles. 223 Measurements: 56-(64)-(76)—78u; W. 42—(44)-(48)-50u; I. 15-(15)-(17)-l8u. Distribution: EUP, Chippewa; WUP, Gogebic. New records for Michigan. 76. Cosmarium nitidulum De Not. West and West, 1905. Monogr. Brit. Desm. 2:197. P1. 64, Figs. 1-3. The truncate-subsemicircular semicells of this species have convex lateral margins which converge grad- ually from broadly rounded basal angles to the small truncate convex apex which may be straight or slightly retuse. The vertical view is elliptic and the cell wall is very minutely punctate. This species can be distin- guished from g, pseudonitidulum Nordst. by the presence of two pyrenoids in each semicell. Measurements: L. 30-41u; W. 23-33u; I. 8-10u. ‘ Distribution: SLP, Wayne (Campbell 1886). 77. Cosmarium variolatum gar. cataractarum Racib. fa. P1. 16, Fig. 7. Messikomer, 1938. Hedwigia. 78:173. Pl. 3, Figs. 35, 36. The semi-elliptic semicells have convex lateral mar- gins which converge upwardly from broadly rounded basal angles to a narrow convex truncate apex. The vertical view is elliptic with each lateral margin possessing a central biundulate protuberance. The semicell wall is coarsely scrobiculate, slightly thickened at the apices 224 and ornamented with a prominent central mucilage pore. Specimens from Delta County possess a more inflated upper semicell than usually present in var. catacactarum, and thus resemble var. rotundum Messikommer which possesses an apical rather than a central pore. The presence of the central pore, the writer believes, is of sufficient importance to assign these organisms as a forma of var. cataractarum. Other specimens from Barry County have more angular and pyramidate semicells, and have larger measurements. The area around the central pore has a highly refractive surface similar to that found in E; pseudopyramidatum var. lentiferum Taylor. Measurements: L. (43)-53u; w. (29)-(30)u; I. 7-7.5u. Distribution: SLP, Barry; EUP, Delta. New records for Michigan. 78. Cosmarium variolatum .Lund. fa. P1. 16, Fig. 13. West and West, 1905. Monogr. Brit. Desm. 2:2-3. P1. 64, Figs. 14-16. The semicells of this species are semi-elliptic. The slightly convex lateral margins converge very gradu- ally from the slightly rounded basal angles toflveery narrow, truncate and subretuse apex. The cell wall is coarsely and conspicuously scrobiculate. The semicells are elliptic in vertical view. Specimens from Emmet County are somewhat shorter and more robust than typical figures. Measurements: L. (30)-32~35u; W. l8-(l9)-2lu; I. (4.5)- 5-6.5u. 225 Distribution: NLP, Emmet. New record for Michigan. 79. Cosmarium Scopulorum Borge. Borge, 1923. Arkiv. f. Bot. 18:12. P1. 1, Fig. 9. This species has truncate-pyramidate to hexagonal semicells. The lower lateral margins are straight and usually slightly divergent, whereas the upper lateral margins are straight or retuse and sharply convergent to the narrowly truncate apex. The vertical view is ellip- tic with the lateral margins slightly tumid in mid-region. The cell wall is smooth. Measurements: L. l6-23.4u; W. l4-l9.5u; I. 3.9-6u. Distribution: Isle Royale (Prescott 1938). 80. Cosmarium maculatum Turner. Turner, W. B., 1893 Kongl. Sv. Vets. Akad. Handl. 25 (5):49. Pl. 7, Fig. 31; P1. 8, Fig. 68. This species has vertical semielliptic to truncate pyramidate semicells. The incision is shallow with a corresponding wide isthmus. The cell wall is strongly and thickly punctate. The semicell is elliptic in vertical view. This species has a superficial resemblance to Egg- marium pyramidatum Breb. but has more shallow sinuses and a much larger size. Measurements: L. l45-l60u; W. 75H; I: 47H- Distribution: NLP, Cheboygan (N a A 1932). ' 81- Cosmarium.pyramidatum. Breb. West and West, 1905. MonOgr. Brit. Desm. 2:199. P1. 64, Figs. 5-7. 226 This large species has truncate pyramidate semicells. The convex lateral margins taper gradually towards the truncate apices. The vertical view is elliptic and the cell wall is finely and densely scrobiculate. This species can be separated from g, pseudopyramidatum Lund. by the usually larger size and the two pyrenoids in each semicell. Measurements: L. 58-(76)-(82)-(94)-100u; w. 41-(51)-(52)- 63u; I. l3.5-(l7)-(2l)-2lu; A. 15-24u. Distribution: SLP, Calhoun, Barry (2), Livingston, Wash- tenaw; NLP, Crawford, Emmet, Cheboygan, also Cheboygan (N & A 1932); EUP, Chippewa, Schoolcraft (2), Delta; WUP, Gogebic (3); Isle Royale (Prescott 1937, 1938 fa.). 82. var. angustatum West and West West and West, 1905. Monogr. Brit. Desm. 2:200. P1. 64, Fig. 8. This variety has less convex sides than the typical and is proportionately longer and narrower. Measurements: L. 90-94-(96)u; W. 48-(53)—54.5u; I. 13.5- 18-(2l.5)u. I Distribution: SLP, Calhoun (Pres. and Mag. 1935); WUP, Gogebic, also Marquette (Pres. and Mag. 1935). 83- Cosmarium.pseudopyramidatum Lund. West and West, 1905. Monogr. Brit. Desm. 2:201. P1. 64, Figs. 9-12. The semicells of this species are truncate-pyramidate or truncate-semi-elliptic in outline. The basal angles 227 are rounded and the convex lateral margins taper gradually to narrowly truncate apices which have rounded angles. The vertical view is elliptic and the cell wall is punctSate. This Species is usually smaller than C, pyramidatum Breb. and has only one pyrenoid per semicell. Measurements: L. (40)-43;(43)-(47)-65u3 W- 25-(27)‘(28)‘ SCH-4011; I - (6-5)-(7)-(9)-14u- Distribution: SLP, Livingston; NLP, Cheboygan, also Che- boygan and Emmet (N & A 1932); EUP, Alger, Schoolcraft, Chippewa; WUP, Marquette, Gogebic; Isle Royale (Prescott 1938). 84. var. stenonotum Nordst. P1. 16, Fig. 12. West and West, 1905. Monogr. Brit. Desm. 2:202. P1. 64, Fig. 13. This variety is much larger than the typical and has slightly retuse lateral margins just below the apex. Measurements: L. 78-80-(90)u; W. 46-48-53u; I. 16-17-(17)u. Distribution: EUP, Alger. New record for Michigan. 85. var. carniolicum Luetk. P1. 17, Fig. 2. Insam and Krieger, 1936. Hedwigia. 76:106. Pl. 2, Fig. 11. This variety has Slightly concave lateral margins. Michigan specimens are slightly smaller than those listed by Insam and Krieger (1936). Measurements: L. (44)-54.2-54.6u; W. (28)-31.4-32u; I. (9)-12.7-13u. Distribution: County records lost. New record for Michigan. 228 86. Cosmarium arctoum var. tatrica Racib. P1. 16, Fig. 9. I West and West, 1908. Monogr. Brit. Desm. 3:42. P1. 69, Fig. 4. This very minute species has cells that are subquad- rate in outline with retuse lateral margins which are very slightly constricted. The semicells are subcuneate with slightly diverging lateral margins. The vertical view is elliptic and the cell wall is smooth. Measurements: L. 9-(10.5)-14u; W. 8-(8.5)-lO.5u; I. 5.2- (6.5)-7u- Distribution: EUP, Schoolcraft. New records for Michigan. 87. Cosmarium minimum West and West P1. 16, Fig. 10. West and West, 1908. Monogr. Brit. Desm. 3:66. P1. 71, Fig. l, 2. This minute species has transversely rectangular semi- cells with slightly rounded angles. The vertical view is elliptic and the cell wall is smooth. Measurements: L. 8.4-(9)-10.5u; W. (7)-7.2-9u; I. 3-(4)-5u. Distribution: SLP, Calhoun. New record for Michigan. 88. Cosmarium norimbergense fa. depressum ‘West and West West and West, 1908. Monogr. Brit. Desm. 3:53. P1. 69, Figs. 28, 29. This organism has transversely rectangular semicells with retuse lateral margins. The apical and basal angles are broadly rounded. The vertical view is elliptic and the cell wall is smooth. 229 Measurements: L. ll-(12.5)-15.6u; W. ll-(ll.5)-15.6u; I- 3.5-(5)-5u. Distribution: SLP, Barry; WUP, Marquette (Pres. and Mag. 1935). 89. Cosmarium exiguum Archer West and West, 1908. Monogr. Brit. Desm. 3:63. P1. 70, Figs. l7, 19. This species has subquadrate semicells with rounded angles. The margins are straight or very slightly convex. The vertical view is elliptic and the cell wall is smooth. Measurements: L. 14.5-29u; W. 9.5-15u; I. 3-6u. Distribution: SLP, Washtenaw (West and West 1898). 90. Cosmarium Dg_Baryi Arch. West and West, 1908. Monogr. Brit. Desm. 3:61. P1. 70, Figs. 14-16; P1. 93, Fig. 2. \ This large species has the cell moderately constricted, the sinus being open and acute. The semicells are sub- quadrate with lateral margins that are straight, slightly retuse or convex. The basal angles are angularly rounded and the apical angles broadly rounded. The apices are convex-truncate or convex. The vertical view is almost circular with slightly compressed margins. The cell wall is minutely punctate. Measurements: L. lOO-ll2-l22u; W. 46-(53)-54u; I. 27.5- (38)-30u. Distribution:' NLP, Crawford; WUP, Houghton; Isle Royale (Prescott 1938). 91. 92. Cosmarium quadratum Ralfs. West and West, 1908. Monogr. Brit. Desm. 3:57. P1. 70, Figs. 6-8. This species has subquadrate (vertically subrectang- ular) semicells which are broadly rounded at the apices. The constriction is moderate with the sinus narrow at the apex, but open outwardly. The basal angles are broadly rounded and slightly protruding and the lateral margins are slightly retuse in some part. This species can be distinguished from,g, cucumis (Corda) Ralfs by the axial chloroplasts, the Open sinus and the protruding basal angles. Measurements: L. 48-(65)-65u; W. 25-(34)-40u; I. 12- (21.5)-25u. Distribution: SLP, Barry(2), Livingston; NLP, Crawford, Emmet, also Cheboygan (N & A 1932); EUP, Alger, Mackinac; WUP, Gogebic. fa. maflor Irenee-Marie IreneeeMarie, 1938. Flor. Desm. de la Reg. Mont. 175. P1. 29, Figs. 3, 4. This form differs from the typical only in its larger size. Measurements: L. 71-(85)u; W. 40-(44)-46u; I. 23.5-(25)- 34u. Distribution: SLP, Washtenaw; Isle Royale (Prescott 1938, g, quadratum). 231 93. Cosmarium plicatum Reinsch West and West, 1908. Monogr. Brit. Desm. 3:60. P1. 70, Figs. 9, 10. ' This species has truncate-pyramidate to vertically subrectangular semicells. The constriction is fairly deep with the sinus linear and closed inwardly but open outwardly. The lateral margins are straight or slightly convex. The vertical view is elliptic and the cell wall is minutely and densely punctate. Specimens from Ingham County have the apical angles more rounded and the apices more convex than those shown by West and West (1908). This species should be compared with g, quadratum Ralfs from which it can be separated by the closed sinus and convex side, and with C, cucumis (Corda) Ralfs. and 93 E227 cucumis Schmidle which have proportionately deeper con- strictions, less rectangular semicells and a usually longer length. Measurements: L. 48-(49)-62u; W. 26-(27)-35u; I. (14)- 16.5-20u. Distribution: SLP, Ingham, also Ca1houn(Pres. and Mag.1935). 94. var. hibernicum W. West West and West, 1908. Monogr. Brit. Desm. 3:61. P1. 70, Figs. 12, 13. ' This variety is usually larger than the typical and has a slightly different semicell shape. The apices are strongly convex in the median part and the lateral margins are slightly concave below the apical angles. 232 Measurements: L. 62.4-96u; W. 35-52u; I. l7-21u. Distribution: Isle Royale (Prescott 1938). 95. Cosmarium angulare Johnson Johnson, 1894. Bull. Torr. Bot. Club. 21.(7)‘290° Pl. 211, Fig. 14. This species has hexagonal-elliptical semicells. The lower lateral margins are slightly divergent and the upper lateral margins are strongly convergent. The api- cal margin is straight. The angles (except the apical angles) are thickened and often acutely pointed. The vertical view is elliptic with two small sharp projections on each lateral margin and sometimes one at each end. The cell wall is minutely punctate. Measurements: L. (28)-30-32u; W. 20-(26)-30u; I. 6-(6.5)- lOu. Distribution: SLP, Calhoun, Barry, Oakland, also Macomb (Johnson 1894); NLP, Roscommon, Crawford; EUP, Schoolcraft; Isle Royale (Prescott 1938). 96. var. octangulare var. nov. P1. 16, Fig. 11. This variety is separated from the typical by the eight- sided semicell, the more exserted apices, and the slightly retuse upper lateral margin. Intermediate forms between the typical form and this variety have been shown in il- lustrations of Prescott (1938) and Irenee-Marie(l938) in which some of the semicells have three sides in each lat- eral margin. The vertical view is elliptic with each 233 lateral margin possessing two sharp projections as in the typical. The angles may or may not be conspicuously thickened and sharply pointed as in the typical. Measurements: L. (21.5)-(26)u; W. (l9)-(24)u; I. (7)-(8.7)u. Distribution: SLP, Calhoun. 97. Cosmarium polygonum (Naeg.) Arch. West and West, 1908. Monogr. Brit. Desm. 3:76. P1. 71, Figs. 32-34. This small species has hexagonal semicells in which the lateral angles are slightly rounded and produced. Both upper and lower lateral margins are slightly retuse and the apical margin is either slightly retuse or straight. The vertical view is elliptic with a single conical pro- tuberance on each lateral margin. The cell wall is smooth or very finely punctate. The conical lateral protuberances in vertical view and the more produced lateral angles separate this species from g. abbreviatum Racib. Measurements: L. 15-2lu; W. 14-18u; I. 3-7u. Distribution: EUP, Schoolcraft, also Luce (N & A 1932); WUP, Marquette. 98. Cosmarium bireme Nordst. P1. 16, Fig. 14. West and West, 1908. Monogr. Brit. Desm. 3:77. P1. 71, Figs. 36, 37. This small species has subellipsoid-hexagonal semi- cells in which the lateral and basal angles are obtuse. The vertical view is elliptic with a more or less long 234 papilla in the center of each lateral margin. The cell wall is smooth. This species is very similar to 9, 22127 ggggm from which it can be distinguished by the smaller size, the less produced lateral angles and the straight lateral margins. Measurements: L. l2-(l2.9)-l3.5u; W. 10-(10.7)-l4.5u; I. 2.5-4-(4.3)u. Distribution: SLP, Calhoun. New record for Michigan. 99. Cosmarium pygmaeum Arch. West and West, 1908. Monogr. Brit. Desm. 3:73. P1. 71, Figs. 22-31. This small species has variably shaped semicells. Usually they are transversely oblong-rectangular, but often transversely oblong-hexagonal. The basal angles are obtuse and the apical angles are obtuse or obliquely truncate. There is a median swelling of each lateral margin. In addition, there is a minute papilla on each lateral margin near the poles. The cell wall is smooth. I The three projections on each lateral margin in vertical view clearly distinguishes this small species. Measurements: L. 7-l2u; W. 7-12.5u; I. 2-5.5u. fiDistribution: SLP, Macomb (West and West 1898). 100. Cosmarium geometricum var. suecium Borge. P1. 16, Fig. 15. Borge, 1921. SJon. Takerns Fauna och Flora. 4:21. Pl. 2, Fig. 21. This small species has hexagonal semicells. The basal angles are broadly rounded (lower lateral margin is convex) 235 and the upper lateral margin is slightly retuse as in the apical margins. The vertical view is elliptic with the lateral margins somewhat tumid, and the middle portion bearing a single conical protuberance. The broadly rounded basal angles and the small size distinguish this species from Q;_polygonum (Naeg.) Arch. and g, bireme Nordst. Measurements: L. 9-(10.5)-l2u; W. 9-(10.5)-llu; I. 3-(3)-4.5u. Distribution: SLP, Calhoun. New record for Michigan. 101. Cosmarium subcapitulum, West. P1. 17, Fig. 5. West and West, 1908. Monogr. Brit. Desm. 3:73. P1. 71, Fig. 17. This species has transversely elliptical-hexagonal semicells. The upper and lower lateral margins converge to form a bluntly rounded angle. The apex is straight or slightly retuse. The vertical view is elliptic or fusiform-elliptic with subacute poles. The cell wall is smooth. Measurements: L. (16.5)—17u; W. (17)-19u; I. 4—(4.3)u. Distribution: SLP, Livingston. New record for Michigan. 102. Cosmarium sphagnicolum West and West fa. P1. 17, Fig. 6. West and West, 1908. Monogr. Brit. Desm. 3:71. P1. 71, Figs. 11-14. This small species has subtrapeziform to transversely hexagonal semicells. The constriction is moderately deep with the sinus short and broadly open. The apical margin 236 is straight or slightly retuse. Each upper angle is fur- nished with a small intramarginal granule. The vertical view is elliptic with a small papilla on each side of the bluntly rounded poles. Specimens from Schoolcraft County agree well with the semicell shape, but the con- striction was less pronounced and the facial papillae Vhre lacking. Measurements: L. (lO)-lO.5-llu; W. (lO)—11-13.5u; I. 5-5.5-(6.5)u. Distribution: EUP, Schoolcraft. New record for Michigan. 103. Cosmarium abbreviatum Racib. P1. 17, Fig. 3. West and West, 1908. Monogr. Brit. Desm. 3:84. P1. 72, Figs. 9-11. This species has elongate-hexagonal semicells in which the angles are slightly rounded and the apices are straight and broadly truncate. The vertical view is ’ narrowly elliptic and the cell wall is smooth. Measurements: L. l4-22-(23.5)u; W. l3-22-(28)u. Distribution: SLP, Inhgam. New record for Michigan. 104. var. mingg' West and West P1. 17, Fig. 4. West and West, 1908. Monogr. Brit. Desm. 3:85. P1. 72, Fig. 12. This variety is typically about half the size of the typical. The writer chooses to include here, extremely small forms (up to 13u long) although the Wests (1908) indicate the length of this variety to be 8u. 237 Measurements: L. 8-(13)u; W. 9-(l3)u; I. (4.5)u. Distribution: SLP, Barry. New record for Michigan. 105. var. planctonicum West and West P1. 17, Fig. 10. West and West, 1908. Monogr. Brit. Desm. 3:85. P1. 72, Fig. 13. This variety has the upper angles more broadly rounded than the typical. Measurements: L. l9-(l9)-29u; w. (19)-22-30u; I. 5.5-(6)-8u. Distribution: WUP, Gogebic. New record for Michigan. 106. C. sexangulare Lund. West and West, 1908. Monogr. Brit. Desm. 3:81. P1. 22, Fig. 3. This moderately large Species has transversely-el- liptic-hexagonal semicells in which the angles are rounded and the upper lateral margins are sometimes slightly con- cave. The constriction is deep, the sinus closed inwardly but open outwardly. The vertical view is elliptic and the cell wall is minutely punctate. Measurements: L. (40)-42u; W. 33-36-(38)u;I. 7-(8)-l2u. Distribution: SLP, Barry; NLP, Cheboygan (N & A 1932), ‘ (Neal 1948); EUP, Mackinac; WUP, Menominee, Houghton; Isle Royale (Prescott 1938). 107- veg. minima Nordst. West and West, 1908. Monogr. Brit. Desm. 3:82. P1. 72, Figs. 4, 5. Typically this forma is about 1/3 the size of the typical. The upper lateral margins and the apical Margins 238 are retuse. Specimens from Calhoun County agree well with the characteristics of this forma except for the straight lateral margins. Measurements: L. l3.5-l5-(15.2)u; W. ll-l2-(l2)u; I. 3-(#)u. Distribution: SLP, Calhoun; Isle Royale (Prescott 1938). 108. Cosmarium rectangulare Grun. West and West, 1908. Monogr. Brit. Desm. 3:54. P1. 70, Figs. 1, 2. Typically this species has subrectangular semicells with basal angles that are subrectangular and rounded. The apical margin is straight and the upper lateral mar- gin is obliquely truncate. The vertical view is subel- liptic and the cell wall is finely punctate. Specimens from Calhoun County have the basal angles more broadly flattened and rounded than illustrations shown by West and West (1908).‘ Measurements: ‘L. 37-(38)-(#3)-47u; W- 30-(32)-(34)-36u; 'I. 9—(9.5)-(10.5)-12. Distribution: ‘SLP, Barry, Calhoun; NLP, Roscommon, also Cheboygan (N & A 1932); EUP, Mackinac; Isle Royale (Pres- cott 1938). 109. var. hexagonum (Elfv.) West and West West and‘West, 1908. Monogr. Brit. Desm. 3:56.. Pl. 70, Fig. #. This variety is usually smaller than the typical and generally is about as long as wide. The upper lateral 239 margins are longer than in the typical and give the semi- cells a more equally hexagonal appearance. The measure- ments are considerably different than those given by West and West (1908) and agree better with measurements of Prescott (1938). Measurements: L. 28-30—(38)-(41)~43u; W. 24-27-(29)(32)- 32u; I. 7-8-9.7-(10.5)u. Distribution: SLP, Washtenaw; Isle Royale (Prescott 1938). 110. Cosmarium refringens Taylor. P1. 17, Fig. 7. Taylor, W. B., 1934. Pap. Mich. Acad. Sci. Arts and Letters. 19:265. P1. 50, Fig. 10. This species has semicells that are hexagonal-oval in outline. The semicell walls are conspicuously thickened, especially in the regions of the lateral angles which are more or less broadly rounded. The vertical view is al- liptic with the lateral walls greatly thickened and some- what tumid. The cell wall is sparsely and finely punctate. This species is very difficult to separate from.g, 2322' doprotuberans Kirchm. The latter has less broadly rounded lateral angles in front view, and more acutely rounded poles in vertical view. Measurements: L. 38-(41)u; W. (34)-35u; I. 8-(9)u. Distribution: Presque Isle. New record for Michigan. 111. Cosmarium pseudoprotuberans Kirchn. West and West, 1908. Monogr. Brit. Desm. 3:82. P1. 72, Figs. 6-8. I a... 240 The semicells of this species are transversely sub- elliptic or hexagonal-elliptic. The lateral angles are obtuse (usually with somewhat thickened walls) and the lower lateral margins are as long or longer than the upper lateral margins. The vertical view is elliptical with slightly tumid and thickened walls in the middle of the lateral margins. The cell wall is punctate. The less rounded lateral angles in front view, and the more broadly rounded poles in vertical View distinguish this species from g, refringens Taylor. 9, Sexangulare Lund. is usu- ally;slightly larger, more angular and without thickened walls in the regions of the lateral angles. Measurements: L. 2O-(34)-(4O)-#1u3 W. 18-(25)-(32)-36u; I. 8-(lO)-(lO.5)-10.5u. Distribution: SLP, Barry, Washtenaw, Livingston, Oakland, also Macomb (Johnson 1895); NLP, Crawford; EUP, Schoolcraft; WUP, Marquette, Houghton; Isle Royale (Prescott 1938). 112. Cosmarium Moerlianum var. brasiliense Borge fa. Pl. l7,Fig.8. Borge, 1918. Arkv. f. Bot. 15(13):36. Pl. 3, Fig. 13. This organism has unequally polygonal semicells. The‘ basal angles of the semicells are two-sided and the upper lateral margins are slightly retuse and convergent toward the straight and narrowly truncate apices. The semicell wall is unornamented except for two subapical granules. A single specimen from.Calhoun County agrees well with this variety although the subapical ornamentation was not clearly granular, but merely slight protuberances from the wall. 111‘ . Measurements: L.(25)—28-29u; W.(l9)-22u; I. 7-{7}u. I; ” 2 1 Distribution: SLP, Calhoun. New record for Michigan. 113. Cosmarium humile var. striatum (Boldt.) Schmidle West and West, 1908. Monogr. Brit. Desm. 3:223. P1. 85, Figs. 21, 22. This small organism has trapeziform-rectangular semi- cells in which the lower lateral margins are slightly bi- undulate and perpendicular to the base and the upper lat- eral margins are retuse and convergent to the apices. The apical margin is broadly truncate with 2-4 undulations. Between the undulations, the semicell wall is slightly thickened and forms short vertical strips. The vertical view is elliptic. Measurements: L. 12.5-15-16u; w. l2-(l3)-l7u; I. 4-(4.3)- 5u. Distribution:. SLP, Oakland; NLP, Cheboygan (Taft 1939). 114. Cosmarium clepsydra Nordst. P1. 17, Fig. 16. West and West, 1908. Monogr. Brit. Desm. 3:98. P1. 73, Figs. 6, 7. .This small species has angularly subsemicircular or broadly subtriangular semicells. The lower lateral mar- gins are two-sided with a blunt angle, and the upper lat- eral margins are retuse, straight or convex and convergent to the truncately rounded apices. The vertical view is elliptical with a broad central protuberance from each lateral margin (Rhomboid with concave lateral margins and obtuse angles). The cell wall is smooth. Measurements: L. 18—21-(21.5)u; W. 18-(2l.5)-22u; I. 4.5-(6)-6.5u. 242 Distribution: EUP, Schoolcraft. New record for Michigan. 115. Cosmarium difficile Luetkm. P1. 17, Fig. 9. West and West, 1908. Monogr. Brit. Desm. 3:96. P1. 73, Figs. 1-3. This species has subrectangular or polygonal semi- cells with rounded angles and retuse lateral and apical margins. The semicell wall is thickened slightly in the regions of retuseness. The semicell wall is finely punc- tate and usually decorated with three transverse rows of minute scrobiculations. Several authors (Taylor 1934, Irenee-Marie 1938) have pointed out that these scrobi- culations are often only weakly or not at all visible. This was true of many of the Michigan specimens examined by the writer. Measurements: L. (23)-25-(25)-38u; W. (15)-16.5-(17)-24u; I. 4-(4)-6u. Distribution: SLP, Barry; EUP, Delta. New record for Michigan. 116. var. sublaeve Luetkm. West and West, 1908. Monogr. Brit. Desm. 3:97. P1. 73, Figs. 4, 5. This variety has less produced apices than the typi- cal and the upper lateral margins are not retuse. The lateral margins may also be straight. Measurements: L. 31-(35)-39u; W. (17)-20-24u; I. 5—6-(6.5)u. Distribution: SLP, Calhoun; WUP, Marquette (Pres. and Mag. 1938). 243 117. var. dilatatum_ Borge Borge, 1925. Arkiv. f. Bot. 19:4. Pl. 1, Fig. 38. This variety has semicells that are unequally poly- gonal in outline and wider at the upper portion than at the base. Measurements: L. 23-(36)-3Su; W. l7.5-(22)-22u; I. 5-(5)-7u. Distribution: NLP, Roscommon, Emmet; Isle Royale (Pres- cott 1938). 118. Cosmarium meneghinii Breb. West and West, 1908. fionogr. Brit. Desm. 3:90. P1. 72, Figs. 29-32. This small species has semicells that are subrectang- ular in the lower part and pyramidate in the upper part. The lower lateral (sometimes slightly retuse) margins are perpendicular or slightly divergent to the base. The up- per lateral retuse margins are convergent to the broadly retuse apices which have rounded angles. The vertical view is elliptic and the cell wall smooth. Measurements: L. l2.5-(22)-24u; W. 9.5—(15)-17u; I. 3-6-(6.5)u. Distribution: SLP, Calhoun, Clinton, also Macomb (Pieters 1894) and Ingham (N & A 1932); EUP, Houghton; Isle Royale (Prescott 1938). 119- Cosmarium angulosum Breb. West and West, 1908. Monogr. Brit. Desm. 3:93. P1. 72, Figs. 35, 36. 244 This small species has subquadrate or subrectangular semicells. The lower lateral margins are straight and perpendicular to the base, and the upper lateral margins are straight and convergent to the straight apical mar- gin. The vertical view is elliptic and the cell wall smooth. Measurements: L. l4.5-(l9.5)-28u; W. (lO.5)-(l3)-l3.5- 18u; I. 3.2-(4.3)-6u. Distribution: SLP, Barry, Calhoun, Washtenaw, also Ionia Wade (1949); WUP, Gogebic.. 120. var. concinnum (Rabh.) West and Wes West and Fest, 1908. Monogr. Brit. Desm. 3:94. P1. 72, Figs. 37, 38. This variety is somewhat smaller than the typical and has the upper angles of the semicells obliquely trun- cate or retuse. Measurements: L. 10.5-(13)-13u; W. 8-(12)-l2u; I. 2.6- (4)-4.5u. Distribution: SLP, Barry, also Ionia (Wade 1949). 121. Cosmarium Regnellii var. minimum Eichl. and Gutw. P1. 17, Fig. 11. Taft, 1945. Ohio. Jour. of Sci. 45:199. P1. 3, Fig. 28. This small apices has trapezoid-hexagonal (almost rectangular in outline) semicells. The lower lateral margins are slightly divergent and much longer than the upper lateral margins which are deeply retuse. The api- cal margin is straight and wide. The vertical view is elliptic and the cell wall is smooth. m .p: U1 Measurements: L. ll-(l2)-l4u; W. ll-(ll)-l2u; I. 3-(4)-4u. Distribution: SLP, Calhoun; WUP, Gogebic. New records for Michigan. 122. fa. basigranulatum Magnotta Prescott and Magnotta, l935. Pap. Mich. Acad. Sci. Arts and Letters, 20:161. P1. 27, Fig. 7. This organism has hexagonal semicells in which the retuse and divergent lower lateral margins and the retuse and convergent upper lateral form broadly rounded lateral angles. The apices are straight and possess rounded ' angles. Several tubercular thickenings are present at each basal angle. Measurements: L. l8-22u; W. l4-l6u; I. 4u. Distribution: SLP, Calhoun (Pres. and Mag. 1935). 123- Cosmarium repandum fa. minor West and West West and West, 1908. Monogr. Brit. Desm. 3:54. P1. 69, Figs. 31, 32. This organism has transversely trapezoid-oblong semicells which are widest above the middle. The slightly retuse lower Iteral margins are very slightly divergent and the upper lateral margins are convex and convergent to the flat apices. This organism resembles g, rectang- gl§33_Grun. but the slight retuseness of the lower lat- eral margins and the greatest width of the semicell above the middle, and the smaller size clearly distinguish it. Measurements: L. 15-22u; W. 14-20u; I. 5.5-8u. Distribution: NLP, Cheboygan (Taft 1939). 1: LI. 246 124. Cosmarium laeve Rabh. West and West, 1908. Monogr. Brit. Desm. 3:99, P1. 73, Figs. 8-19. The semi-elliptic or semi-oblong elliptic (sometimes almost pyramidate with convex lateral margins) semicells of this species have a narrowly truncate and retuse apices. The vertical view is elliptic and the cell wall is punctate or punctate-scrobiculate. Measurements: L. 15-(17)-34u; W. 11.5—(13)-23u; I. 2.8-(3.3)-6.7u. Distribution: SLP, Barry; NLP, Emmet, also Emmet (N & A 1931). 125. var. octangularis (Wille) West and West P1. 17, Fig. 15. This small organism has angular semicells which are about eight-sided. The lateral margins have three straight or slightly curved sides. The apices are retuse. The vertical view is elliptic. Specimens from Calhoun County agree well with the description of this organism, although they are shorter and stouter and have broader and less retuse apices than those illustrated by West and West (1908). They appear identical with Irenee-Marie's (1938) illustra- tion of g, repandum var. minor West and West, and super— ficially similar to Q3 Meneghini var. nanum Wille (as il- lustrated by Taylor 1934) and Q, laeve Rabh. as illustrated by Insam and Krieger (1936). The measurements of the Spec- imens above except for Irenee-Marie's, were slightly 247 greater than the Michigan specimens. The writer believes that the slightly retuse apices and angular expression sometimes found in g, laeve, necessitates the assigning of these specimens to the var. octangularis. Measurements: L. (17)-21u; W. (12.5)-l7-19u; I. (4.5)-6.5-7.5u. Distribution: SLP, Calhoun. New record for Michigan. 126. Cosmarium quadratulum (Gay) De Toni P1. 17, Fig. 14. 4est and West, 1908. Monogr. Brit. Desm. 3:121. P1. 72, Fig. 333 P1. 93, Fig. 4. This small species typically has transversely sub- rectangular semicells with the lateral margins and apices.,e'tusc and the basal and upper angles obliquely-truncate. The vertical view is elliptic, and the cell wall is smooth. Collections from several counties are very similar to those illustrated by West and West (1908). However, other specimens appear somewhat intermediate with 93 Regnelli Wille. These specimens are roughly octangular in outline, with the lower lateral margins slightly divergent and ex- tending about half the length of the semicells. Just above the lower lateral margins, there is a sharp con- striction so that a small shoulder is formed, above which the lateral margin is perpendicular or slightly conver- gent. They appear closest to individuals of g, quadrat- glgm_illustrated by Insam and Krieger (1938). Measurements: L. l2-(l7)-20u; W. lO-(13)-(15)-l7u; I. 2-(3.5)-6u. 248 Distribution: SLP, Barry, Calhoun; EUP, Chippewa; WUP, Gagebic. New record for Michigan. 127. var. applanatum Insam and Krieger P1. 17, Fig. 12. Insam and Krieger, 1936. Hedwigia. 76:107. Pl. 3, Fig.17. This small organism has trapezoid semicells. The basal angles are broadly rounded and slightly produced, and the lateral margins are slightly concave. The apical margins are straight. Michigan specimens from Barry County are similar to this variety, although the apices are slightly retuse. Measurements: L. (l2)-l2.6-l7u; W. (10.5)-11.8-l4.5u; I. 3.7-(4)-4.2u. Distribution: SLP, Barry. New record for Michigan. 128. Cosmarium Regnesii var. tritum West P1. 17, Fig. 13. West and West, 1908. Monogr. Brit. Desm. 3:38. P1. 68, Figs. 35, 36. This very small organism has semicells which are irregularly hexagonal. The convex and divergent lower lateral margins form a broadly rounded lateral angle with the deeply retuse and convergent upper lateral margin. The apices are straight and broadly truncate. The sinus between the semicells is Open and obtuse at the apex. Specimens from Barry County are assigned here, although the lateral angles are more broadly rounded than figures shown by West and West (1908). They should be compared with g, polygonum Naeg. from which they differ in the 249 shorter and open sinus and the lack of central protuber- ances on the semicell, and with C, Regnellii Wille which has a deep linear sinus. Measurements: L. 6.6-8.5-(10.5)u; W. 6.6-8.5-(10.5)u; I. 3.7-5—(5.5)u. Distribution: SLP, Barry. New record for Michigan. Key to Species of Cosmarium Section B. Semicells with Granulate or Verrucose Walls Outline of semicells circular, semi- circular, subcircular or subsemi- circular . . . . . . . . . . . . 2 Outline of semicells otherwise . . . 8 2. Outline of semicells circular or subcircular . . . . . . . (129) C; praegrande 2. Outline of semicells semicir- cular or subsemicircular . . 3 Margin of semicells crenate . . . . (130) gucaelatum Margin of semicells not crenate, but entire . . . . . . . . . . . . . 4 4. Semicells with a large su raisth- mial granule (l or more) . . 5 4. Semicells without large conspi- cuous supraisthmial granules . 6 Semicells with an intramarginal series of verrucae . . . . . . . . (141) g, taxichondrum Semicells without an intramarginal series of verrucae . . . . . . . . (131; Q, monomazum var. polymazum and 132 var. tristiéhum 6. Sinus deep and linear . . . . . (133) g, intermedium 6. Sinus shallow and open . . . . 7 7. 11. ll. 13. 13. 15. 15. 250 Width of isthmus 15-17u . . . . . . (134) g, excavatum var. dupIo-major Width of isthmus 11-l4u . . . . . . (135) g. isthmium 8. Semicells circular in transverse . View . O C O O C O C O C C O 9 8. Semicells not circular in trans- verse view . . . . . . . . . 11 Cell length over 65u . . . . . . . . (136) Q, tesselatum Cell length less than 65u . . . . . 10 10. Cell wall ornamented with trans- verse rows of nodules . . . . (139) g;_annulatum 10. Cell wall ornamented with trans- verse rows of rounded warts (granules) . . . (of. (137) g. cylin- dricum) (138)C . elegantissimum var. simplicius Semicells transversely elliptic, sub- elliptic, oblong-elliptic or reni- form (rarely rhomboid-elliptic}. . l2 Semicells otherwise . . . . . . . . 29 12. Semicells distinctly reniform . 13 12. Semicells not distinctly reni- form . . . . . . . . . . 17 Apices of semicells elevated . . . . (157) C, ornatum Apices of semicells not elevated . . l4 14. Cell length below 15u, cell wall minutely punctate-granu- late . . . . . . . . . . . . (41) 93 subdepressum 14. Cell length above l5u, cell wall with well developed granules. 15 Cell length below 40u . . . . . . . 16 Cell length above 40u . . . . . . . (146) Q, reniforme 16. Central area of semicell above isthmus with five vertical series of granule . . . . . . (148) g, subreniforme 17. 17. 19. 19. 21. 21. 23. 23. 25. 25. 251 16. Central area of semicell not as above . . . . . . . . . . (149) C, Netzerianum Semicells elliptic, broadly ellip- tic or subelliptic, (rarely rhom- boid elliptic) . . . . . . . . . . 18 Semicells otherwise . . . . . . . . 29 18. Semicells rhomboid~e11iptic (sometimes with a slight apical retuseness) . . . . . 19 18. Semicells not rhomboid elliptic 2O . Cell length below 25u . . . . . . . (151) Q, Wittrockii var. quasidepressum Cell length above 25u . . . . . . . (150) C, Raciborskii 20. Semicells ornamented with gran- ular teeth . . . . . . . . . . 21 20. Semicells ornamented with gran- ules . . . . . . . . . . 22 Granules restricted to or just within lateral margin . . . . . . . . . . (158) 9: dentatum Granules present upon lateral and within apical margin . . . . . . . (152) C. Eloiseanum var. depressum 22. Semicells narrowly oblong-ellip- tic o O O O O O O O O O O o O 23 22. Semicells not narrowly oblong- . elliptic O O O O O 0 O O 0 0 2L," Apices slightly elevated . . . . . . (159) g, commissurale var. crassum , Apices not slightly elevated . . . . (160) g, trachypleurum var. minus 24. Granules arranged in pairs . . (154) 93 ordinatum 24. Granules not arranged in pairs. 25 Length of cells more than 50u . . 26 27 Length of cells less than 50u . . . 252 26. Length of cells more than 80u . (164) g, Brebissonii 26. Length of cells less than 80u . (163) C. logiense 27. Upper central region of the semicell wall with two strongly developed warts . . . . . . . . . . . . . . (155) C, bimamillatum 27. Upper central region of the semicell wall without warts . . . . . . . . ~ 28 28. Central region of semicell wall with granules arranged in some pattern . . . . . . . . (cf. 28. Central region of semicell wall without granules arranged in a pattern, granules arranged regularly in vertical series upon entire semicell wall . . (161) g, portianum 29. Semicells more or less rectangular or subrectangular (occasionally with convex apices). . . . . . . . 30 29. Semicells more or less pyramidate, truncate-pyramidate, subpyrami- date, trapeziform, or trapeziform- like with slightly rounded lateral margins . . . . . . . . . . . . . 44 30. Semicells vertically rectangular or subrectangular (with con- vex apices) . . . . . . . . . 31 30. Semicells transversely rectangu- lar or subrectangular . . . . . 32 31. Lateral margins nearly parallel, ex- cept near apices; constriction often sublinear . . . . . . . . . (165) g, amggggm 31- Lateral margins subparallel; con- / striction a slight notch . . . . . (107) 9: pseudoamoenum 32. Margin of semicells crenate-un— ’ dulate . . . . . . . . . . . (206) g, crenatum 32. Margin of semicells not crenate- undulate . . . . . . . . . . 33 33. 35- 37- 39. 39. Semicells uniformly granulate . . Semicells not uniformly granulate . 34. Length of semicells above 60u . 34. Length of semicells below 60u Cells small, less than 40u long, with a sharp papilla-like protub- erance in the central area of the semicell wall . . . . . . . . . . Cells large, more than 40u, long, without sharp papilla-like protub- erance as above . . . . . . . . . Semicells with two transverse linear series of granules which are separated by scro- biculations . . . . . . . 36. Semicells with numerous gran- ules, but not arranged in two linear series and not separ- ated by scrobiculations . 36. Lateral margins of semicells in ver- tical view strongly tumid; gran- ules small . . . . . . . . . . . . var. minus) Lateral margins of semicells in ver- tical view not tumid, granules larger . . . . . . . . . . 38. Semicell wall punctate between granules . . . . . . . . . 38. Semicell wall not punctate be- tween granules . . . . . . . Apices slightly retuse in median portion . . . . . . . . . . . . Apices straight or slightly convex . 40. Lateral margins parallel . . 40. Lateral margins slightly diver- gent O O O I O O O O O O O 253 37 34 (168) Q: ungerianum var. subtriplicatum 35 (169) g, novae-semilae var. sibericum_'i 36 (171) 9: triplicatum (170) g, nudiceps (cf. (182) C. biretum 177) Q, subbroomei 38 39 41’ (176) C. quadrum var. sfiblatum 40 (172) 9: margaritatum (178) g, conspersum 7 var. latum n 41. 41. 43. 43. 45. 45. 47. 47. 49. 254 Lateral margins parallel . . 42 Lateral margins slightly divergent . (178) 9: conspersum_ var. latum 42. Cell length more than 50u . . 7 43 42. Cell length less than 50u . . . (180) g, pseudobroomgi . . . (179) g, conspersum Apical margins convex var. rotundatum Apical margins slightly retuse . . . (175) g, quadrum 44. Cells as long as wide, or slightly longer than wide 45 44. Cells 1 1/4 times longer than wide, or longer . . . . . . . 75 Upper central region of semicell with granules in a transverse row, semi- cell hexagonal with strongly punc- tate wall . . . . . . . . . . . (181) C, mediogemmatum Semicells without the above combina- tion of characteristics . . . . . 45 46. Width of semicell greatest at upper lateral angle . . . . . (182) C. biretum fa. minus 46. Width of semicell not greatest at upper lateral angle . . . 47 Cell length usually less than 42u . 57 Cell length usually more than 42u . 48 48. Apex of semicell truncate and elevatEd o o o o o o o o o o ' 1‘9 48. Apex of semicell not elevated . 53 Semicell with two inflations on each lateral margin (invvertical view). (183) C. Turpinii Semicell with a single inflation or none on each lateral margin (in vertical view) . . . . . . . . . . * 50 50. Central region of semicell wall smooth . . . . . . . . . . . 52 53- 53- 55. 55. 57. 570 50. Central region of semicell wall not smooth . . . . . . Lateral margins with a subrectangu— lar incision between apical and basal lobes; cell length 34-45u . (184) Lateral margins undulate between api- cal and basal angles; cell length / 55-8011 0 o o o o o o o o c o o o o (180) 52. Cell length usually less than 48u; basal angles broadly rounded . . . . . . . . . . . (187) 52. Cell length usually more than 48u; basal angles subrectang- ular . . . . . . (188) var o Semicell wall with a reticulat net- work formed by six triangular de- pressions around each granule . . (189) Semicell wall not as above . . 54. Semicell without lateral infla- tions in vertical view . . . (190) 54. Semicells with lateral infla- tions in vertical view . . . Lateral intramarginal granules ar- ranged in pairs . . . . . . . . . Lateral intramarginal granules not arranged in pairs . . . . . . (191) 56. Semicells subrtrapeziform, lower lateral margins subpar- allel, upper lateral margins slightly convergent . . . . . (210) 56. Semicells trapeziform-semicircular; lateral margins convex and convergent . . . . . . . . . (192) Semicells without lateral inflations in vertical view . . . . . . . . . (194) Semicells with lateral inflation in vertical view . . . . . . . . . [0 IO 255 g, protractum g. quasillus 9: vexatum g3 sportella subnudum . cosmetum 54 . margaritiferum \fl U) 9: radiosum . costatum IO Q, formosulum 93 furcatospermum LI“? CO 61. 256 58. Semicells almost semicircular, with lateral margins slightly angular . . . . (195) C. pseudotaxi- chondrum var. Foggii 58. Semicells otherwise . . . . . 9 U) Lateral inflation (in vertical view) papilla-like . . . . . . . . . . . (196) g, Blytii Lateral inflation (in vertical view) not papilla-like . . . . . . . . 60 60. Central region of semicell wall not as hbbuul . . . . . . . . 61 60. Central region of semicell wall with two transverse rows of large granules (3 upper, 2 lower), the granules inter~ spersed with punctations . . (197) C; quinarium Lateral margins crenate and/or emar— ginate, with distinct sinuses be- tween granules or pairs of gran- ules . . . . . . . . . . . . . . . 66 Lateral margins entire or slightly undulate-crenulate, with very shal- low sinuses between granules or pairs of granules . . . . . . . . 62 62. Central area of semicell with about five vertical series of granules . . . . . . . . . . 63 62. Central area of semicell with- out five vertical series of granules . . . . . . . . . . 64 Cell length less than 30u . . . . . (198) g, Kiellmanii Cell length more than 30u . . .(148)c _, subreniforme 64. Supraisthmial region of semicell wall with either a single gran- ule, or if more than one gran~ ule, then with one granule much larger than others . . . (199) 93 Boeckii 64. Semicell otherwise . . . . . . 65 257 65. Granules of the same size, or if of two sizes, larger granules restric- ted to central area of semicell wall . . . . . . . . . . . . . . . ch. (202) g. cruciatum) 200) C, punctulatum 65. Granules of two different sizes, the larger granules extending vertical- ly from the apex to near isthmus . (203) C, anisochondrum 66. Each lateral margin with four minute basal crenations and one large upper crenation . . (204) g, calcareum 66. Each lateral margin otherwise . 67 67. Central area of semicell ornamented with three elongate granules, one of which, at least, is divided in- to a short and a long part . . . . (205) C. sexnotatum var. tFistriatum 67. Central area of semicell ornamented otherwise . . . . . . . . . . . . -68 68. Crenations, especially upper lateral ones, sharply angular, often emarginate . . . . . . 72 68. Crenations with broadly rounded angles . . . . . . . . . . . 59 69. Outline of semicell nearly rectangu- lar O O O O C C C O . . . . . . (206) g, crenatum_ 69. Outline of semicell trapeziform—semi- circular or trapeziform-pyramidate 7O 70. Central area of semicell with vertical series of granules 71 70. Central area of semicell with- out vertical series of gran- ules . . . . . . . . . . . . (207) g, madestumL 71. Lateral crenations (counting apical and basal angles) 5: . . . . . . . (208) g, subcrenatum 71. Lateral crenations four (counting apical and basal angles) . . . . (209) C, subprotumidum 73- 73. 75- 77. 77- 79- 79- {0 U1 0‘3 72. Central area of semicell wall 3; with 5—7 vertical granulate - ridges . . . . . . . . . . . (210) 93 costatum 72. Central area of semicell wall with 3-5 subvertical series of granules . . . . . . . . . 73 Cell length over 25u . . . . . . . (211) g, subcostatum Cell length below 25u . . . . . . . 74 74. Cell width l8-21u . . . . . (212) g, subcostatum var. EEEEE 74. Cell width 21.5-23.5u . . . . . (213) g, norvegicum Lateral margins entire, usually orna- mented with granules . . . . . . . 82 Lateral margins crenate, crenations sometimes finely granulate . . . . 76 76. Crenations bigranulate . . . . 77 76. Crenations not bigranulate . . 79 Twelve or more crenations in each semicell . . . . . . . . . . . . . 78 Less than twelve crenations in each semicell . . . . . . . . . . . . . (214) C, nasutum 78. A single basal transverse row of granules distinctly isolated from upper transverse rows of granules (in central ornamented region of semicell wall . . . (215) C, binum 78. A single basal transverse row of granules not isolated from upper transverse rows of gran- ules . . . . . . . . . . . . (216) g, subspeciosum Lower central region of semicell wall with at least five vertical series Of granules o o o o o o o o o o o 80 Lower central region of semicell wall without five vertical series of granules o o o o o o o o o . . . . 81 81. 83. 83. 85. 259 80. Cell length more than 65u . . (218) g, supraspeciosum 80. Cell length less than 65u . . . (219) C, speciosum Granules on semicell wall simple . . (220) g, speciosum var. simoIEx Granules on semicell wall not simple, but flattened warts . . . . . . (224) g, ochthodes 82. Semicell decorated with triangu- lar thickenings of the wall; thickenings arranged in series around a single large scrobi— culation so that the wall ap- pears to have reticulate lin- ear grooves with a coarse scrobiculation at each inter- section . . . . . . . . . . . (223) g, decoratum 82. Semicell wall otherwise . . . . ' 83 Lateral margins deeply concave in central part . . . . . . . . . . (227) 93 retusum Lateral margins straight or convex . 84. Granules restricted to marginal region, sometimes with sever- al transverse rows near base of semicells . . . . . . . . 85 84. Granules distributed over entire semicell, except in some cases where the central region of the semicell wall will be smooth or have greatly re- duced granules . . . . . . . 86 Base of semicells with 1-4 short transverse rows of granules . . . (cf. (230) c. ovale var. Prescottii) (228) 9: denticulatum fa.~Bo?EEIi Base of semicells without short transverse rows of granules . . . (229) g, ovale 86. Central region of semicell wall SIIIOOth o o o o o o o o o o o 87 86. Central region of semicell wall granulate (sometimes faintly) 0”) co 87. 87. 89. 91. 91. 129. 130. 260 Cell length more than 85u . . . .(23 l)C . Gayanum var. eboracense Cell length less than 85u . . . . . (233) g, Botrytis var. mediolaeve 88. Semicell with slight or well de- fined lateral inflations (in vertical view) . . . . . 89 88. Semicell without lateral infla- tions (in vertical view) . . 91 Length of cell less than 50u . . . . (197) 9: quinarium Length of cell more than 50u . . . . 9O 90. Width of isthmus lO-l5u . . . (234)C . Botrytis var. subtumidum 90. Width of isthmus over l6u . . . (235) g, Botrytis var. tumidum Cell length usually more than 90u . (237) g, tetraophthalmum Cell length usually less than 90u . (232) g: Botrytis Cosmarium praegrande Lund. West and West, 1908. Monogr. Brit. Desm. 3:150. P1. 77, Fig. 19. This large species has semicells that are almost circular. The sinus opens widely from an acute apex. The cell wall is ornamented with conical warts over the entire surface, except for a small apical region. The wall is punctate between the conical warts. Measurements: L. 91-(10l)-104u; W. 56-61-(64)u; I. 20-23.4-(26u). Distribution: EUP, Delta; Isle Royale (Prescott 1938). Qgsmarium caelatum' Ralfs.. West and West, 1908. Monogr. Brit. Desm. 3:134. P1. 75: Figs. 5-7. 261 The subsemicircular semicells of this species have strongly crenate margins. The lateral margins are bi- crenate (rarely tricrenate) the lower crenations larger than the upper, and the apical margins are quadri-crenate. The apical and upper lateral crenations are ornamented with two or three marginal granules which are components of four transverse linear series of granules (some of which may be larger and in the distinct linear series) ex- tending across the lower part of the semicell face. The vertical view is elliptic with tumid lateral margins. The .margin is evenly granulate and the intramarginal re— gions have short vertical series of granules. Measurements: L. 40-51u; W. 36-42u; I. 12-15u. Distribution: WUP, Marquette (Pres. and Mag. 1935). 131. Cosmarium monomazum var. polymazum Nordst. P1. 17, Fig. 17. West and West, 1908. Monogr. Brit. Desm. 3:140. P1. 76, Fig. 12. The subsemicircular semicells of this species have the intramarginal region ornamented with 16—20 flat emar— ginate warts. Three prominent gransles form a transverse series in the central region of the semicell wall and a single larger granule occurs Just above the isthmus. The vertical view is elliptic with three granules in the mid- dle of each lateral margin, and with two longitudinal (long axis) intramarginal linear series of flat emarginate warts. 262 Measurements: L. 32-(32 -39u; w. 32-(34)-39u; I. 9-(10.5)-l4u. Distribution: SLP, Barry; NLP, Cheboygan; EUP, School- craft. New record for Michigan. 132. Cosmarium monomazum var. tristichum. West and West West and West, 1898. Journ. Linn. Soc. Bot. 33:305. Text Fig. 4. This variety is similar to var. polymazum except for the central region of the semicell where nine gran- ules are arranged in three transverse series. Measurements: L. 32u; W. 36u; I. llu. Distribution: SLP, Washtenaw (West and West 1898). 133. Cosmarium intermedium Delp. West and West, 1908. Monogr. Brit. Desm. 3:138. P1. 76, Fig. 10. This species has pyramidate-semicircular semicells with broadly rounded apices and basal angles. The ver- tical view is elliptic. The cell wall is ornamented uniformly and in concentric series by granules. The limits of this species are poorly defined and various authors have extremely different measurements. Measurements: L' 45~50u (79u according to West and West 1908); W. 33—35u (6lu according to West and West 1908); I. 12-14u (l9u West and West 1908). Distribution: SLP, Wayne (Campbell 1886); NLP, Emmet (N a A 1932). 263 134. Cosmarium excavatum var. duplo-major Lund. P1. 17, Fig. 18. West and West, 1908. Monogr. Brit. Desm. 3:148. P1. 94, Fig. 3. The semicells of this species are subsemicircular to subcircular. The semicells are separated by a shallow, broad sinus, the isthmus being broad and somewhat elongated. The lateral margins are convex, although sometimes slightly flattened. The vertical view is circular. The semicell walls (in front view) are ornamented with 5-7 transverse rows of granules so that the semicell margin has about 13-15 granules. ' Measurements: L. 39-(44)-47u; W. 21.5-(22)-25u; . I. 15413-17111. ' Distribution: SLP, Calhoun. New record for Michigan. 135. Cosmarium isthmium West ‘ West and West, 1908. Monogr. Brit. Desm. 3:145- P1. 77: Figs. 7-10; P1. 94, Fig 2. This species has semicircular semicells with sub- rectangular basal angles. The sinus between the semi- cells is broadly open and of a semicircular or semi- elliptic outline. The cell wall is ornamented with 7-10 vertical series of granules in each one of which there are 6-7 granules. Each lateral margin has 15-20 granules. The vertical view is almost circular with 25-28 granules around the margins. This species can be distinguished . from g. excavatum var. duplo-major Lund. by the wider (A, 26k cells, and the deeper sinus, and from g, portianum.Arch. by the semicell shape. ‘ Measurements: L. 40-(42)-(u5)-48u; w. 25-(25)-(26)-28u; I. (lO.5)-ll-(13)-l3.5u. istribution: SLP, Calhoun, Oakland; NLP, Presque Isle, also Cheboygan (Taft 1939); EUP, Schoolcraft; WUP, Houghton. 136. Cosmarium tesselatum (Delp.) Nordst. Irenee-Marie, IQRB. Le. Nat. Canad. 75(5—7):171. Pl. 3, Fig. #. This large species has subcylindrical cells that are very slightly constricted. The lateral margins are sub- parallel and the apices convex. The semicell wall is ornamented with 13-17 horizontal (also oblique) series of granules. The vertical view is circular. Measurements: L. 132-149.7u; w. 67.6u; 74u; I. 54-61u. Distribution: SLP, Washtenaw (Johnson 1894). 137. Cosmarium cylindricum Ralfs. West and West, 1912. Monogr. Brit. Desm. #:43. P1. 94, Fig. 7. (P1. 94 in Vol. 3., 1908). This species has small subcylindrical cells which are very slightly constricted. The semicells are sub- quadrate or subrectangular in outline with slightly di- vergent lateral margins and convex~truncate apices. The vertical view is circular. The semicell walls are orna- mented densely with small granules. Measurements: L. 38-57u; W. l9-24u; I. 15-17u. Distribution: NLP, Emmet (N a A 1932). 265 138. Cosmarium elegantissimum var. simplicius West and West, P1. 18, Fig. l West and Heat, 1898. Journ. Linn. Soc. Bot. 33:308. P1. 17, Fig. 7. This organism has cells which are cylindrical with convex apices. The constriction is very slight so that the sinus is distinguished only by the lack of granules. The cell wall is ornamented by seven vertical series of large rounded warts (granules). There are about seven warts in each vertical series. The vertical view is circular. Measurements: L. 54-(63)-64u; W. 22-(25)-28u; I. 21-(23)-24u. Distribution: SLP, Calhoun; NLP, Roscommon; WUP, Gogebic. New record for Michigan. 1395 Cosmarium annulatum (Naeg.) De Bary West and West, 1912. Monogr. Brit. Desm. 4:39. Pl. 102, This species has subcylindrical cells which are very slightly constricted. The semicells are rectangular (with convex-truncate apices) with 4-5 undulations on each lateral margin corresponding to the 4-5 transverse rows of small nodules upon the cell wall. The vertical view is circular, with fourteen marginal undulations. Measurements: L. 36-54u; W. 16-23u; I. 14.5-21u. Distribution: NLP, Cheboygan (N a A 1932). 266 140. var. elegans Nordst. P1. 18, Fig. 2. West and West, 1912. Monogr. Brit. Desm. 4:40. Pl. 102, Figs. 16-18. This variety is distinguished primarily from the typical by the bigranulate crenations. Specimens from Delta County have the subapical row (of each semicell) of crenations possessing short vertical ridges, the next lowest row made up of single granules and the bottom three rows possessing the typical two granules on each crenation. This expression appears identical with speci- mens of Taylor (1934) from New Foundland. Measurements: L. 40-(49)-57.5u; W. lT-(19)-29u; I. (17)u. Distribution: EUP, Delta. New record for Michigan. 141. Cosmarium taxichondrum Lund. West and West, 1912. Monogr. Brit. Desm. 4:45. Pl. 103, Figs. 11-13. The semicircular semicells of this species have the basal angles conspicuously thickened and sometimes slightly convergent. The apices are slightly flattened or sub- truncate. The cell wall is punctate. Additional orna- mentations of the semicell wall are the single large supraisthmial granule and the two (occasionally one) trans- verse arcuate series of granules in the upper median re- gion. Usually there are 3-5 granules in the upper_row and three in the lower row in the specimens examined by the writer. West and West (1912) however, state that R) O\ N there are three in the upper series and five or six in the lower series. The vertical view is elliptic with a‘ variable mumber of granules on each lateral margin. Measurements: L. 36-(44)-50u; W. 32-(46)-46u; I. 9-(10)-14u. Distribution: SLP, Muskegon (Transeau 1917); NLP, Emmet, also Cheboygan (N a A 1932); Isle Royale (Prescott 1938). 142. var. unigranulatum Prescott Prescott and Magnotta, 193R. Pap. Mich. Acad. Arts, Sci. and Letters. 20:162. P1. 25, Figs. 5, 6. The presence of only the single supraisthmial granule separates this variety from the typical and other var- ieties. Specimens taken by the writer from the same lake from which Prescott described this variety have only the single supraisthmial granule, but agree more favorably with the semicell shape of the typical than those illus- trated by Prescott. The measurements are also smaller than the var. unigranulatum. Measurements: L. (42)-53-54.3u; W- (42)—45-46.8u; I. (10.5)-17-17.5u. Distribution: SLP, Calhoun, also Calhoun (Pres. and Mag. 1935). 4 143. var. n3g2g_ Turner P1. 18, Fig. 8. IréheeéMarie, 1949. Le. Nat. Canad. 76:(8-10); Pl. 5, Fig. 6. This variety is separated from the typical by lack of any granular ornamentation upon the semicell wall. . 268 This variety is very close to g, obsoletum (Hantzch) Reinsch from which it can be separated by the less depressed and more angular semicells, the usually smaller width, and the lack of a lateral swelling in vertical view. Measurements: L. (32)—(36)-40u; W. (jO)-(38)-43u; I. (lO.5)—13u. Distribution: Delta; WUP, Marquette. New records for Michigan. 144. var. obsoletumiforme var. nov. P1. 18, Fig. 7. This variety differs from the typical and from the varieties of the typical in the possession of greatly thickened basal angles which are submammillate and con- vergent (including possible mucilage pores). The semi- cell wall granulation is similar only to var. unigranu- 13232 Prescott in the possession of single supraisthmial granules. It should be compared with g, smolandicum Lund. which lacks the supraisthmial granule and possesses pap- illae at the basal angles, and with g, smolandicum var. angustatum (Hantzsch) Reinsch which has a different semi- cell shape and which lacks the supraisthmial granule. Measurements: L. 34u; W. 34u; I. 7u. Distribution: NLP, Presque Isle; JUP, Gogebic. 145. var. IréheefiMgrig nob. P1. 18, Fig. 6. Irenee-Marie, 1938. Flor. Desm. de la Reg. Mont. 186. P1. 27, Figs. 6-8. This variety differs from the typical and other var- ieties by the possession of a series of small granules 269 upon or Just within the apical margin. Irenee-Marie (1938) illustrates several individuals (Figs. 7, 8) that possess a median transverse row of three granules on the semicell wall but the Michigan specimens from Crawford County lack these granules as does Fig. 6 of Iréhee-Marie!s. This organism was described by Irenee-Marie as a new var- iety of g, taxichondrum, but without a name. The writer believes that the discovery of this organism in Michigan corroborates Irenee—Marie's original finding and therefore necessitates the addition of a variety name. Measurements: L. 30—(32)-36u; W. 29-(32)-33u; I. 7-(T.5)-8u. Distribution: NLP, Crawford. New record for Michigan. 146. Cosmarium reniforme (Ralfs) Arch. West and West, 1908. Monogr. Brit. Desm. 3:157. P1. 79, Figs. 1, 2; P1. 82, Fig. 15. This species has reniform semicells. The sinus is deep, narrow and closed, although dilated at the apices. The vertical view is elliptic. The cell wall is orna- mented by round granules arranged in oblique (sometimes irregularly vertical) series. There are about 25-33 granules along the lateral margin of each semicell in front view and approximately 38 in vertical view. Speci- mens from Barry County are much smaller than typical measurements. The writer has been unable to find any reference in the literature to a small expression of this species. 270 Measurements: L. (36)-4h-67u; w. (32)-36-60u; I. 9-(lO.5)-20u. Distribution: SLP, Barry, also Macomb. (Campbell 1898), Ionia (Wade 1949) and Livingston (N & A 1932); NLP, Presque Isle, also Cheboygan (N & A 1932, Welch 1938a); WUP, Marquette. 147. var. elevatum West and West West and West, 1908. Monogr. Brit. Desm. 3:159. P1. 79, Fig. 6. This variety is separated from the typical by the less reniform semicells, the subrectangular basal angles and the subparallel lower lateral margins. A few speci— mens from Mackinac County were intermediate between the typical and this variety. The semicells were slightly reniform but more elevated and with less rounded angles. It agrees favorably with Fig. 7, P1. 79 (West and West 1912) which is identified as a form approaching var. 312‘ m. Measurements: L. (48)-52-5uu; N. 36—(38)-46u; I. (10.5)— 14u. Distribution: SLP, Washtenaw (West and West 1898); NLP, Emmet (N & A 1932); EUP, Mackinac fa. 1&8. Cosmarium subreniforme Nordst. West and West, 1908. Monogr. Brit. Desm. 3:243. P1. 88, Fig. 6. The subreniform semicells of this species have trun- cate apices. The crenulate lateral (7-8) and apical (fi-B) 271 margins are ornamented with fine granules. Within the margin, there are additional small granules which are ir- regularly arranged. A central protuberance above the is- thmus possesses five vertical series of granules. The elliptic semicell (in vertical view) has a broad central granulate protuberance on each lateral margin, the re- maining portion of the semicell walls, except for the central part, has curved transverse rows of small granules. Measurements: L. 36-37u; w. 31-33u; I. lO-llu. Distribution: SLP, Ionia (Wade (1949); NLP, Cheboygan (N a A 1932). ’ 149. Cosmarium Netzerianum Schmidle fa. P1. 18, Fig. 3. Schmidle, 1895. Oest. Bot. Zeit. 45:20. P1. 15, Fig. 19. This species has elliptic semicells with convex lat- eral margins and convex apices. The sinus is fairly deep, Open and inwardly sharply rounded. The semicell wall is ornamented with rounded granules in transversely oblique series. The wall is smooth between the granules. The vertical view is elliptic. A single specimen from Oak- land County is assigned here questionably. The specimen is distinctly more rectangular—reniform than Schmidle's (1895) illustration, and the sinus is almost closed. The semicell wall wall is ornamented with deep subcircular- elliptic depressions so that the semicell margin appears to be granulate although it is the cell wall projections between adjacent depressions which appear to be granules. Insam and Krieger (1936) show a form of g, Netzerianum similar to Schmidle's but it is impossible to determine whether the wall is pitted or granulate. .Punctations also are present in the cell wall. Measurements: L. (32)-48u; w. (28)-42u; I. (18)u; Distribution: SLP, Oakland. 150. Cosmarium Raciborskii Lag. Homfeld, 1929. Pflanzen. 12:53. Pl. 7, Fig. 7#. This species has rhomboid-elliptic semicells with obtusely rounded lateral angles and convex apices. The semicell is ornamented with fine, irregularly disposed granules. The vertical view is elliptic, the middle lateral margins straight and the poles obtusely rounded. Measurements: L. 54.6-(55)u; w. (55)—55u; I. (23)-25u. Distribution: EUP, Delta; Isle Royale (Prescott 1938). 151. Cosmarium Wittrockii var. quasidepressum Skuja P1. 17, Fig. 19. Skuja, 1930. Act. Hort. Bot. Univ. Lat. 4:67. Pl. 3, Fig. 30. This organism has cuneate (unequally hexagonal) semicells which are constricted by a deep and gradually opening sinus. The apical margins are slightly retuse and both the upper and lower lateral margins are convex, the latter margin longer, so that the greatest width is in the upper half of the semicell. The semicell wall is ornamented with vertical series of small round granules. The vertical view is elliptic. Specimens from Menominee 273 and Marquette Counties agree well with the description of this organism although the granules are not as large as specimens illustrated by Skuja (1930). Measurements: L. (18)—19-(19)-23u; W. l6-(l9)-2lu; I- (6)-7-(8)-9-bu. Distribution: WUP, Menominee, Marquette. New records for Michigan. 152. Cosmarium Eloiseanum var. depressum West and West West and West, 1896. Trans. Linn. Soc. Bot. Ser. 2., 5 (5):248, P1. 15, Fig. 23. ' The semicells of this organism are broadly elliptic, with convex lateral margins and flattened apices. The ornamentation of the semicell consists of large conical granules arranged(about 25) along the lateral margins, (about 6) within the apical margin and (about 6) within each lower lateral margin and (2-6) occasionally above the isthmus. The semicell wall is punctate except for the central region which is conspicuously scrobiculate. Measurements: L. 77-95-(96)u; W. 54-(56)-753 I. 15-(21)—26u. Distribution: NLP, Emmet; Isle Royale (Prescott 1937, 1938, 93 Eloiseanum). 153. ggsmarium ordinatum (Boerg) West and West P1. 17, Fig. 20. Krieger, 1932. Archiv. f. Hydrobiol. Suppl. 11:181, P1. 13, Fig. 2. This small species has elliptic semicells with broadly a._ rounded lateral margins and straight or slightly convex 274 apical margins. The semicell wall is ornamented with 4-5 transverse rows of granules (warts), the central nine granules being emarginate and appearing as paired granules. The vertical view is elliptic with sharply truncate gran- ules on the lateral margins and the rest of the semicell is ornamented with transverse rows of granules. Measurements: L. l9—(2l.5)-22u; w. 19-(19)-21u; I. (5)-6-8u. Distribution: SLP, Calhoun; EUP, Chippewa. New records for Michigan. 155- Cosmarium bimamillatum Krieger Krieger, 1932. Archiv. f. Hydrobiol. Suppl. 11:171, P1. 13, Fig. 3. This species has elliptic semicells with broadly rounded lateral angles and flattened apices. The orna- mentation consists of two large granules (warts) upon the upper middle semicell wall, two short rows of large punctae, one below the two granules, the other in the supraisthmial region, three concentric rows of small gran- ules arranged within each lateral margin, and a single row of similar granules subapically placed. The vertical view is elliptic with two large granules in the middle of each lateral margin. The rest of the semicell has trans- verse rows of granules except the central part which is smooth. Measurements: L. 32-#Ou; w. 30-33u; I. ll-20u. Distribution: Isle Royale (Prescott 1938). 275 156. Cosmarium pseudoornatum Eichl. and Gutw. P1. 18, Fig. 5. Eichler and Gutwinski, 1894. Rospr. Wydz. Matem. orz. Akad. Umiej. Cracovie 28:170, Pl. 5, Fig. 25. This species has elliptic semicells with convex lat- eral margins and straight or slightly convex apices. Granular ornamentation consists of about 17-23 granules along each semicell margin, about four curved vertical series within each lateral margin and one or two trans- verse series withhthe apical margin. The central region of the semicell has a protuberance upon which are arranged 4-6 central granules surrounded by 10-14 others in a con- centric series. This species is close to g, ornatum Ralfs. but lacks the elevated apices. The Michigan spec- imens from Menominee County are considerably larger than original typical measurements and are assigned here ques- tionably as they may represent specimens of g, ornatum with reduced apices, although they agree very favorably with illustrations of Messikommer (1927). Measurements: L. 26-(4l)-u; w. 29-(4l)u; I. 9-(lO.5)u. Distribution: WUP, Menominee. New record for Michigan. 157- Cosmarium ornatum Ralfs. West and West, 1908. Monogr. Brit. Desm. 3:151, P1. 78, Figs. 1-10. This species has reniform semicells with truncate apices that are slightly elevated. The lateral margins which are broadly rounded, except below the apices_where 276 they are slightly retuse, are ornamented with 6-9 gran-‘ ules on the margin and a variable number with the mar- gin. The apices have about seven prominent granules. The central part of the semicell wall possesses a pro- tuberance upon which are arranged granules of variable size and number in short vertical on concentric series. The vertical view is elliptic with broadly rounded poles and conspicuous lateral granular protuberances. The cen- tral area of the semicell is smooth in this view. Measurements: L. 32-(32)-(38)-41u; w. 32-(33)-(38)-4lu; I. (9)-9 5-(13)-13u. Distribution: SLP, Barry (2), Livingston, Oakland also Macomb (Pieters 1894); NLP, Presque Isle; EUP, Chippewa, Delta; WUP, Gogebic (2); Isle Royale (Prescott 1938). 158. Cosmarium dentatum Wolle Wolle, F. 1892. Desm. of the U.S., 83. P1. 16, Fig. 15. This large species has broadly elliptic semicells in which each broadly rounded lateral margin is orna- mented with 6-10 dentate granules. The apex is slightly flattened and the sinus is gradually opened from an acute apex. The cell wall is punctate. Specimens from Presque Isle County are considerably smaller than Wolle's (1892), measurements. Measurements: L. (ll3)-l45-l60u; W. (74)-90-lOOu. 277 Distribution: SLP, Wayne (Campbell 1886), Washtenaw West and West 1898); NLP, Presque Isle, also Cheboygan (Welch 1938a). 159. Cosmarium commissurale var. crassum Nordst. P1. 19, Fig.3. West and West, 1908. Monogr. Brit. Desm., 3:155, P1. 78, Figs. 15-16. This organism has narrowly oblong-elliptic semicells with truncate and very slightly produced apices. The sinus is linear and narrowly open. The broadly rounded lateral angles possess 6-8 granules on the margin and 8-10 within the margin. The apices have about seven gran- ules. The central region of the semicell possesses a broad protuberance which has a variable number of granules arranged in an irregular concentric pattern. The vertical view is elliptic with broadly rounded poles and with broad lateral granulate protuberances. The lateral mar- gins are strongly constricted below the poles which are also granulate. Measurements: L. 28-(28)-37u; W. 31-(32)-43u; I. 9-(lO)- l3u. Distribution: SLP, Barry (2), Calhoun, Livingston; EUP, Schoolcraft; WUP, Gogebic (2). New records for Michigan. 160. Cosmarium trachypleurum var. EEEEE. Racib. West and West, 1908. Monogr. Brit. Desm. 3:173, P1. 81, Figs. 4-5. This species has narrowly oblong-elliptic semicells with the margins (apical and lateral) bearing small acute 278 granules. The granules within the lateral margins are arranged in several oblique and irregular rows and within the apical margin in a single transverse and slightly curved row. The central region of the semicell wall has a center granule surrounded by a circleJ5 or 6 more. The vertical view is elliptic with granulate, rounded poles and with slight lateral, tri-granulate protuberances. This species is easily separated from g, commissurale var. crassum Nordst. by the lack of elevated apices. Measurements: L. 31—34.5u; W. 26.5-33u; I. 8-5-l2u. Distribution: NLP, Cheboygan (N and A 1932). 161. Cosmarium Portianum Arch. West and West, 1908. Monogr. Brit. Desm. 3:165, P1. 80, Figs. 4-7. This species has elliptic semicells which are sep- arated by a deep sinus opening gradually from a broadly rounded (occasionally subrectangular) apex, the isthmus thus being slightly elongated. The semicell wall is ornamented with lO-l2 vertical series of granules which number about twenty along the margin. The vertical view is elliptic. Measurements: L. 30~(38)-40u; W. 22-(28)-3pu; I. 8-(1o.5)-13u. Distribution: SLP, Barry (2), Calhoun, Livingston, Oak- land, Washtenaw, also Wayne (Campbell 1886), Macomb (Pie- ters 1894), Muskegon (Transeau 1917), and Calhoun (Pres. and Mag. 1935 fa.); NLP, Cheboygan, Presque Isle, Crawford, .1, it; 279 Emmet, Roscommon; also Cheboygan (N and A 1932); EUP, Delta (2), Alger, Schoolcraft; WUP, Houghton, Isle Royale (Prescott 1938). var. nephroideum Wittr. P1. 18, Fig. 4. N West and West, 1908. ionogr. Brit. Desm. 3:167, Fl. 60, Figs. 10, 11. This variety is smaller than the typical; the granules are somewhat smaller and the semicells have a subreniform or semicircular-elliptic outline. Measurements: L. 25-(27)-3lu; W. (21)-22-27u; I. 7—(8)-10u. Distribution: SLP, Livingston; EUP, Schoolcraft. New records for Michigan. Cosmarium lofigiense Biss. West and West, 1908. Monogr. Brit. Desm., 3:163. P1. 80, Figs. 1, 2. This species has elliptic-subreniform semicells with the basal-angles somewhat rounded and slightly Subrectang- ular. The apical margin may be somewhat flattened or slightly retuse in the central part. The vertical view is elliptic. The semicell wall is ornamented with about seventeen vertical series of granules with 28-33 of the granules along the margin. The proportionately greater length, the smaller granules and the different cell shape separate this species from g, reniforme (Ralfs) Archer. Measurements: L. 61-65u; W. 48-50u; I. 16-18u. Distribution: SLP, Lapeer. (N and A 1932). 280 164. Cosmarium Brebissonii Menegh. West and West, 1908. Monogr. Brit. Desm., 3:161. P1. 79, Figs. 10, 11. The semi-elliptic semicells of this species have broadly rounded basal angles and a flattened and subtrun- cate apex. The sinus is narrowly linear but closed only in the central position. The vertical view is elliptic- with broadly tumid lateral margins. The semicell wall is irregularly covered with large conical granules which are reduced in size or completely lacking in the central re- gion of the semicell (in vertical view). Measurements: L. 88-lOOu; W. 67-79u; I. 22-26u. Distribution: EUP, Schoolcraft (N & A 1932). 165. Cosmarium amoenum Bréb. P1. 19, Fig. 2. West and West, 1912. Monogr. Brit. Desm. 4:29, P1. 102, Figs. 1-4; Pl. 103, Fig. 9. The semicells of this species are rounded-quadrate with slightly convex lateral and apical margins. The constriction is moderate with the sinus slightly open or nearly linear. The semicell wall is ornamented with 6-9 vertical (somewhat irregular) series of granules. There are 8-10 granules in each series and about 20-25 along each semicell margin. The vertical view is broadly el- liptic (almost circular). Zygospores were found in Schoolcraft County and as the writer has been unable to find references to this reproductive structure of this species, the description is included here. Zygospore spherical, outer wall smooth, inner wall regularly and uniformly ornamented by deep circular depressions; di- ameter 46u. _ Measurements: L. 42-(53)-56u; W. 24-(28)—30u; I. 11-(15)-l7u. Distribution: SLP, Barry (2), Berrien, Ingham, Living- ston; NLP, Crawford, Emmet; also Cheboygan (N and A 1932, Welch 1938b); EUP, Chippewa, Schoolcraft (4): WUP, Goge- bic (3), Houghton. 166. var. mediolaeve Nordst. P1. 18, Fig. 11. West and West, 1912. Monogr. Brit. Desm. 4:31, Pl. 102, Figs. 5, 6. This variety is separated from the typical by the lack of granules in the central part of the semicell wall and the two transverse rows of granules across the base of the semicells. Measurements: L. 39-(43)-(48)-76u; W. 21-(23)-(26)-(28)- 40u: I. 9-(11)-(15)-20u. Distribution: SLP, Calhoun, Barry (2); NLP, Emmet. New records for Michigan. 167. Cosmariumpseudoamoenum Wille West and West, 1912. Monogr. Brit. Desm. 4:31, Pl. 102, Figs. 7-9. The small, almost cylindrical cells of this Species are slightly constricted with the sinus only a small and 282 open indentation. The semicells are more or less oblong with straight or slightly convex lateral margins, and a broadly rounded apex. The cell wall is ornamented with granules that are either arranged in vertical series or in angirregular pattern. The vertical view is subcircu- lar—elliptic. The writer has not seen this species which appears very similar to g, amoenum_Breb. West and West (1912) report that g, pseudoamoenum Wille is proportion- ately narrower and the sinus is not as deep. The typical presence of only a single pyrenoid in each semicell is questioned. 8 Measurements: L. 44-59u; W. 18-29u; I. 15-24u. Distribution: NLP, Cheboygan (N and A 1932). 168. Cosmarium Ungerianum var. subtriplicatum ‘West and West West and West, 1908. Mon. Brit. Desm., 3:196. P1. 91, Fig. 7. This organism has oblong-rectangular semicells with rounded upper angles. The constriction is deep and the sinus is linear. The semicell wall is partly ornamented with granules of somewhat variable size. The upper lat- eral angles have four short oblique rows(four granules in outer row, two in inner row) of granules Just within the margin and two somewhat smaller granules upon the margin. There is also a single granule Just within api- cal margin. The basal angles have two small intramar- ginal and three small marginal granules, whereas the cen- 283 tral region of the semicell has a few scattered ones. The larger size and the different arrangement of granules separates this species from g, triplicatum.Wolle. Measurements: L. 67u; W. 54; I. 22u. Distribution: NLP, Cheboygan (N and A 1932). 169. Cosmarium novae-semiliae var. sibericum Boldt. West and West, 1908. Monogr. Brit. Desm., 3:36, P1. 68, Figs. 17, 18. This small organism has the cells deeply constricted by a broad and open sinus. Each semicell is rectangular in general outline with the central region of the apices retuse. The rest of the apical margin and the lateral margins are denticulate (about five per half of semicell). The semicell wall has 2-3 denticulations within each lat- eral margin and the central region has a sharp papilla- like protuberance. The vertical view is elliptic with a papilla-like protuberance on each lateral margin and two transverse rows of denticulations (one within margin and one upon margin). Measurements: L. 17-18u; W. 15-15.5u; I. 6.5-7u. Distribution: Isle Royale (Prescott 1938). 170- Cosmarium nudiceps Johnson Johnson, 1894. Bull. Torr. Bot. Club. 21(7):289. P1. 211, Fig. 12. ' This species has rectangular semicells with strongly convex apices. Each lower lateral margin has two small 284 granules, one above the other, occasionally with one or two more in the series. The upper central region of the semicell wall is ornamented with nine oblique (divergent) rows of large granules, 2-4 granules in_each row. The vertical view is elliptic with the lateral margins gran- ulate. Measurements: L. 48-50u; W. 36-40u; I. 12-14u. Distribution: SLP, Macomb (JOhnson 1894); NLP, Cheboygan (N and A, 1932). 171. Cosmarium triplicatum Wolle Wolle, 1892. Desm. of the U.S.:79. P1. 22, Figs. 3-6. This species has subrectangular semicells with rounded angles. The basal angles each have three flattened gran- ules on the margin and 2-3 within the margin. Each of the apical angles, which are more rounded than the basal angles, possesses three flattened granules upon the mar- gin and three within the margin. Usually there are two or three additional granules of the same size within the apical margin. The upper central region of the semicell wall possesses two transverse rows of similar granules, each granule separated from the adjacent one by conspicu- ous scrobiculations. Measurements: L. 44-(58)-58u; W. 34.5-(#0)-4hu; I. lO-(lO.5)-l#u. Distribution: SLP, Washtenaw, Oakland, Barry, Jackson, also Washtenaw (Johnson 1894, West and West 1898). WUP, Houghton. 285 172. Cosmarium margaritatum (Lund.) Biss. West and West, 1912. Monogr. Brit. Desm. 4:18, P1. 99, Figs. 8, 10. This species has subrectangular semicells with slightly convex apical and lateral margins and with rounded basal and apical angles. The sinus between the semicells is deep, narrowly linear, closed but open at the base. The semicell wall is ornamented by oblique series of granules, about twelve granules in a series and about 28-32 of the granules arranged around the semicell margin. Distinct punctations occur between the granules. The vertical view is oblong-elliptic with convex lateral margins. Measurements: L. 60-105u; W. 56-82u; I. 19-31u. Distribution: SLP, Barry; NLP, Cheboygan; also Cheboygan (N and A 1932); EUP, Alger, Mackinac: Isle Royale (Pres- cott 1937, 1938). 173- var. mi22£_(Boldt) West and West. P1. 20, Fig. 1. West and West, 1912. Monogr. Brit. Desm. 4:19. P1. 99, Fig. 9. This form is separated from the typical by the smaller size. Measurements: L. 44-(52)-60u; W- 38-(48)-51u; I. 12.5-16-(19)u. Distribution: SLP, Barry, Calhoun, Oakland, Washtenaw; NLP, Emmet3'EUP, Delta; WUP, Menominee, Marquette. New records for Michigan. 286 174. var. ridibundum Taylor. P1. 19, Fig. 8. Taylor Pap. Mich. Acad. Sci., Arts, and Letters, 19:257. P1. 52, Fig. 8. This variety can be separated from the typical by the hollowness of the granules and the especially strong development of the isthmial row of granules. Specimens from Emmet County are slightly smaller than typical‘ I measurements. Measurements: L. (75)-85-88u; W. (60)-64u; I. 18-(19)u. Distribution: NLP, Emmet. New record for Michigan. 175. Cosmarium quadrum Lund. West and West, 1912. Monogr. Brit. Desm. 4:20. Pl. 100, Figs. 3-6. This species has subrectangular semicells with.straight or slightly convex lateral margins and with rounded angles. The apical margin is straight or slightly retuse. The semicell wall is ornamented with numerous vertical series of solid granules, the margin of the semicell showing about 34-37 of the granules. The vertical view is oblong- elliptic with straight parallel sides. The lack of punc- tations between the granules easily separates this species from g, margaritatum (Lund.) Biss. The slightly retusa or straight apices separates it from g, conspersum var. latum (Breb.) West and West and the larger size from Q. pseudobrogmeji Wolle . Measurements: L. 60-83u; W. 54-74u; I. 18-29u. Distribution: NLP, Emmet (Taft 1939). 287 176. var. sublatum (Nordst.) West and West. P1. 21, Fig. l. West and West, 1912. Monogr. Brit. Desm. 4:21. Pl. 100, Fig. 2. This variety is separated from the typical by the hollow granules and the intergranular punctations. It resembles g, margaritatum (Lund.) Biss. but can be easily distinguished by the different shape of the semi- cell and the hollow granules. Measurements: L. (85)u; W. (77)u; I. 2lu. Distribution: NLP, Presque Isle. New record for Michigan. 177. Cosmarium subbroomei Schmidle fa. West and West P1. 19, Fig. l. West and West, 1912. Monogr. Brit. Desm. 4:23, P1. 100, Fig. 11. Typically, this species has oblong-rectangular (slightly trapeziform) semicells with slightly rounded angles and slightly convex apical and lateral margins. The semi- cell wall is finely granulate. The central region of the wall has the granules more conspicuous, but more irregu~ larly arranged. The vertical view is elliptic with a very slightly granulated protuberance in the middle of each lateral margin. A few specimens from.Barry County agree well with the description of West‘s form but the lateral margins are slightly divergent (but not as sharp as in g, biretum Breb.) and the upper lateral margins are more angularly rounded. Measurements: L. (32)-42u; W. (30)-38u; I. (9)-l2u. Distribution: SLP, Barry. New record for Michigan. 288 178. Cosmarium conspersum var. latum (Breb.) West and West West and West, 1912. Monogr. Brit. Desm., 4:15. P1. 99, Figs. 5, 6. This large organism has subrectangular semicells with distinctly divergent lateral margins and usually convex apical margins. The semicell wall is uniformly granulate, the granules arranged in about 13-15 vertical (often somewhat irregular) rows. The vertical View is elliptic. Measurements: L. 88-107u; W. 76-88u; I. 27.5-34u. Distribution: SLP, Macomb (West and West 1898); NLP, Emmet. 179. Cosmarium conspersum var. rotundatum Wittr. West and West, 1912. Monogr. Brit. Desm. 4:16. P1. 99, Fig. 3. This variety has semicells with subparallel lateral margins and less convex apical margins than var. EEEEEI (Breb.) West and West. The semicell shape is thus more perfectly rectangular than var. latum, The semicell wall has the typical (as in var. latum) arrangement of granules in vertical and transverse rows. The vertical view is elliptic. Measurements: L. 86-110u; W. 66-80u; I. 25-33u. Distribution: NLP, Cheboygan (N and A 1932). 180. (Cosmarium pseudobroomei Wolle West and West, 1912. Monogr. Brit. Desm., 4:22. P1. 100, Figs. 7, 8; Pl. 103, Fig. 7. 289 This Species has transversely oblong-rectangular semicells with straight or slightly convex lateral and apical margins. The angles are slightly rounded. The semicell wall is ornamented with about 9-12 vertical rows of small solid granules, the semicell margin show- ing 23-32 of these granules. The vertical view is oblong with subparallel lateral margins and broadly rounded poles. Measurements: L. 33-38u; W. 29-36u; I. 8.5—l2u. Distribution: SLP, Wayne (N and A 1932); NLP, Cheboygan, (N and A 1932, Welch 1938a); Isle Royale, (Prescott 1938). 181. Cosmarium mediogemmatum West and West West and West, 1897. Jour. Bot., 35(412):ll8. P1. 367, Fig. 11. This species has hexagonal semicells. Typically, the central region of the semicell wall is decorated with three transverse rows of large granules (two in upper, three in middle, two in lower) surrounded by scrobicula- tions. There is also a single granule at each basal angle. The semicell wall is also coarsely punctate. The vertical view is elliptic with several granules in the middle of'each lateral margin. A single specimen from Oakland County resembled this Species except for the presence of only a single transverse row of three granules. Measurements: L. 36-(36)-38u; W. (28)-29-3lu; I. (8.5)-9.5u. Distribution: SLP, Oakland. New record for Michigan. 290 182. Cosmarium biretum var. migu§_ Hansgirg. P1. 19, Fig. 4. West and West. Monogr. Brit. Desm. 4:26. (Pl. 101, Figs. 1-8 typical). This organism has subrectangular trapeziform semi- cells with straight or slightly convex lateral margins which diverge upwardly. Thus, the widest part of the semicell is Just below the convex apical margin. The semicell wall is ornamented with small granules arranged either in vertical series or irregularly. The vertical view is elliptic. Measurements: L. 38-(38)-52u; W. (32)-35-52u; I. l3-(14)-l9u. Distribution: SLP, Barry; NLP, Roscommon. New records for Michigan. 183. Cosmarium Turpinii Breb. West and West, 1909. Monogr. Brit. Desm. 3:189. P1. 82, Figs. 16 and 17; P1. 83, Fig. 1. 8 This species has truncate—pyramidate semicells. The basal angles are broadly rounded and the lateral margins are very slightly concave and distinctly convergent to the truncate apex. The semicell wall is ornamented with granules that are irregularly arranged and usually some- what reduced in size towards the center. The central region has two slight protuberances upon which larger granules are irregularly disposed. The vertical view is narrowly elliptic with two granulate protuberances on each lateral margin. 291 Measurements: L. 60-(75)-77u; W. 50-64-67u; I. l4-(17)—18u. Distribution: SLP, Jackson; also Gratiot (West and West 1898) and Ionia (Wade 1949); NLP, Newaygo (N and A 1932); EUP, Mackinac, also Delta (N and A 1932); WUP, Menominee. 184. Cosmarium protractum (Naeg.) De Bary West and West, 1908. Monogr. Brit. Desm. 3:181. P1. 82, Fig. 8; P1. 94, Figs. 4, 5. This species has trilobed semicells with a subrec- tangular sinus between the apical and basal lobes. The lateral lobes are broadly rounded and the apical lobes are truncate with rounded angles and with slightly retuse margins. The lobes are ornamented with irregular rows of granules and the central region of the semicell poss- esses a protuberance upon which are granules arranged in several concentric series. Measurements: L. 34-45u; W. 33347u; I. 8.5-12u. Distribution: SLP, Oakland, also Wayne(Campbell 1886), and Washtenaw (N and A 1932); NLP, Cheboygan (N and A 1932); WUP, Houghton (N and A 1932); Isle Royale (Taylor 1935, Prescott 1938). 185. fa. basigranulatum fa. nov. P1. 18, Fig. 9. This new form is identical with the typical except for the presence of a large supraisthmial granule upon I each semicell. Measurements: L. (42)u; W. (42)u; I. (10.5)u. Distribution: NLP, Presque Isle. 292 186. Cosmarium Quasillus Lund. West and West, 1908. Monogr. Brit. Desm. 3:188. P1. 92, 5'1 U.) ig. *3 he trapeziform to pyramidate-truncate semicells of this species have lateral margins converging from rounded basal angles to the slightly produced apices. The basal angles are finely crenate and the lateral margins are un- dulate with the undulations increasing in size upwardly. The apical margin is slightly biundulate but not granu- lated. The central region of the semicell has a protub- erance upon which several concentric series of granules are arranged. Two of the granules near the base are often distinctly larger than others. The rest of the semicell is ornamented with granules arranged in radiating and concentric series, except a small smooth area around the central protuberance. The vertical view is elliptic with a central granulate protuberance upon each lateral margin. Measurements: L. 55-80u; W. 50-74u; I. 15-21u. Distribution: SLP, Wayne (Johnson 1894, N and A, 1932), Washtenaw (Johnson 1894); NLP, Emmet (N and A 1932). 187. Cosmarium vexatum West. West and West, 1908. Monogr. Brit. Desm. 3:187. P1. 92, Fig. 4. This truncate~pyramidate semicells of this Species have convex and convergent lateral margins arising from bluntly rounded basal angles to the truncate and slightly 293 produced apex. The lateral margins are undulate with 6-7 undulations increasing in size upwardly. The apices are straight or slightly subundulate. The semicells walls are ornamented with small granules arranged in a somewhat irregularly radial and subconcentric pattern. The granules gradually decrease in size inwardly toward the center which is smooth. The vertical view is oblong- elliptic with granulate poles and smooth central lateral protuberances. Measurements: L. 41-43u; W. 36-38u; I. 13.5-14u. Distribution: NLP, Emmet (N and A 1932). 188. Cosmarium §portella var. subnudum West and West. West and West, 1908. Monogr. Brit. Desm. 3:186, P1. 82, Fig. 14. The semicells of this variety are truncateopyramidate. The lateral margins which are granulate, converge grad- ually from slightly rounded basal angles to the truncate apex which also has a granulate margin. The semicell wall is punctate in the center but ornamented within the margins with several irregularly concentric and radial series of small granules. Measurements: L. 50-53u; W. 39-4lu; A. 22u; I. 14.5-24u. Distribution: Isle Royale (Prescott 1938). 189- Cosmarium cosmetum West and West. West and West. Trans. Linn. Soc. Bot. 2nd Ser. 5 (5):2SO. P1. 15, Fig. 4. 294 The oblong-trapeziform semicells of this species have a very characteristic ornamentation. The convex lateral margins possess 7-8 granules and the apical mar- gin is smooth. The semicell wall has one or two granules within each basal angle. The upper part of the semicell has numerous equally spaced granules around each of which there are about six triangular depressions in the wall. This arrangement thus creates a very conspicuous reticu- late pattern. Measurements: L. (49)-51-(52)-57u; W. 42-44-(44)-48.5u; I. (lO.5)-l2.5-(l3)-15u. Distribution: SLP, Barry; NLP, Emmet, also Emmet (N and A 1932). 190. Cosmarium_margaritiferum Menegh. West and West, 1908. Monogr. Brit. Desm. 3:199. P1. 83, Figs. 4-11. The broadly-pyramidate-truncate (Somewhat trapezi- form) semicells have slightly convex lateral margins (each with 7-9 granules) which converge from rounded basal angles towards the straight or slightly convex apical margin. The semicell walls are granulate with the granules in the center and within the basal angles and lateral margins somewhat larger than others, the former being surrounded by fine scrobiculations. Fine and dense punctations occur between all the granules. The vertical view is elliptic with granules in the middle of each lateral margin larger and with the central area smooth. R) \O \J‘. Measurements: L. 47-59u; w. 41-56u; I. l3-16u. Distribution: SLP, Wayne (Campbell 1836) and Macomb (Pieters l894); Isle Royale (Prescott 1937). 191. Cosmarium radiosum Wolle Wolle, 1892. Desm. of the U.S.z97. P1. 22, Figs. 21,22. The species has trapeziform semicells with convex lateral margins and flattened apices. The semicell mar- gin is ornamented with numerous granules which continued in about thirty-five radiating series inwardly to the middle of the semicell. There is a protuberance above the isthmus upon which there are about eight vertical or slightly divergent short series of granules. The vertical view is elliptic with a central protuberance upon each lateral margin. Measurements: L. 56-58u; w. 50u. Distribution: EUP, Delta. (N and A 1932). 192. Cosmarium formosulum Hoff. West and West, 1908. Monogr. Brit. Desm. 3:241. P1. 88, Figs. 1-3. The trapeziform semicells of this species have con- vex lateral margins that are 6-7 crenate, the three up- per crenations bigranulate and the lower crenations entire. The apices are truncate, usually four crenulate, with the angles obtuse or faintly bigranulate-emarginate. Granules within the semicell margin are arranged in con— centric or radiating series, usually binate except for 296 the innermost series. The central region has a broad protuberance upon which there are 5-7 vertical series of granules. The vertical view is narrowly elliptic, with rounded and crenulate poles and with a broad cren- ulate protuberance on each lateral margin. Measurements: L. RO-SOu; w. 34-40u; A. 12-17u; I. 10-15.5u. Distribution: SLP, Washtenaw, Jackson; NLP, Cheboygan and Emmet. All records by Nichols and Ackley(l932) ex- cept for Washtenaw. 193. var. Nathorstii (Boldt) west and west West and West, 1908. Monogr. Brit. Desm., 3:242. P1. 88, Figs. #,5. This variety is separated from the typical by the greater width of the semicells and the larger granules upon the central protuberance. Measurements: L. hfi-SB-(60)u; W. 42-(51)-V2u; I. ll-(13)-15u. Distribution: SLP, Calhoun, also Macomb (West and Fest 1898). 194. Cosmarium furcatospermum Nest and West West and West, 1908. Monogr. Brit. Desm. 3:206, P1. 81, Figs. 10, 11; P1. 84, Figs. 8—10. The truncate-semicircular or trapeziform-semicircular semicells of the species have crenate—granulate lateral margins (4~5 crenations per margin). The truncate and sometimes slightly exserted apices have 4-6 slight undu- 297 lations. Just within the margin of the semicell there are one or two rows of granules, the rest of the semi- cell being smooth or minutely punctate. The vertical View is elliptic with undulate-granulate poles. ieasurements: L. 18-(21.5)-26u; W. l6.5-(l9)-22u; I. 5.7-(6.5)—7.5u. Distribution: SLP, Calhoun; NLP, Crawford; EUP, Mack- inac; Isle Royale (Prescott 1938). 195. Cosmarium pseudo—taxichondrum var. Foggii Taylor fa. P1. 18 . Fig. 10 Taylor, 1934. Pap. of Mich. Acad. Arts, Sci., and Letters, 19:262. P1. 54, Figs. 9 and 11. This fairly small species has truncate—triangular (almost subsemicircular with angular lateral margins) semicells which are at least 2 1/2 times wider than long. Typically, the basal angles are thickened, convergent and ornamented with divergent, rounded teeth. In addition, there is a single granular tooth just within the basal margin. The semicell wall is otherwise ornamented with three widely Spaced granules, the central one larger than the laterals. Occasionally there is an additional granule within each basal angle. The vertical View is narrowly elliptic with three widely separated granules on each lateral margin, and with acute poles. Specimens from Chippewa County agree favorably with the character- istics of this variety although the granular ornamenta- tion is somewhat reduced and the size of the semicells somewhat smaller. Measurements: L. (21.5)-24-26u; w. (28)-32-34u; I o 5.5-(6)u. Distribution: EUP, Chippewa. New record for Michigan. 196. Cosmarium Blytii Wille. West and West, 1908. Monogr. Brit. Desm. 3:225. P1. 86, Figs. 1-4. This small species has trapeziform semicells with lateral margins that have four crenations (including . basal and apical angle). The upper crenations may be emarginate. One or two series of small granules are located Just within the lateral margins and the central region of the semicell possesses a single subpapillate granule. The vertical view is elliptic with a single conspicuous granule in the middle of each lateral margin. Measurements: L. lO-(15)-l9u; w. 7-(13)-l6u; I. 2.8-(3)-5.5u. Distribution: SLP, Barry, Calhoun, Livingston, also Kalamazoo (N and A 1932); EUP, Alger, Schoolcraft. 197- Cosmarium quinarium Lund. West and West, 1908. Monogr. Brit. Desm. 3:216. P1. 85, Figs. 9-10. The broadly pyramidate-truncate semicells have con- vex lateral margins converging from the obtusely rounded bases to the rounded angles of the truncate apices. Each lateralihargin is ornamented with 7-8 granules (the margin thus appearing undulate) and the apical margin 299 has about four undulations. The intramarginal granula- tion consists usually of a single series of large rounded or acute granules. The central region of the semicell possesses two transverse rows of the large granules (3 in upper, 2 in lower), interspersed with at least three punctations. Measurements: L. 38-(42)-42u; w. 32-(32)-(34)-36-38u3 I. (9)-9.5-llu. Distribution: SLP, Calhoun (Pres. and Mag. 1935, not Fig. 4, P1. 26 which is g, Boeckii); NLP, Emmet; EUP, Alger, Schoolcraft; WUP, Gogebic. 198. Cosmarium Kjellmanii Wille West and Fest, 1903. Monogr. Brit. Desm. 3:219. P1. 85, Fig. 13. The truncate-pyramidate or trapeziform-subsemicircu- lar semicells of this species have convex lateral margins converging upwardly from obtusely rounded bases to the narrow truncate apex. The semicell wall is granulate, the granules upon each lateral and margin numbering about 5-6, the granules within the margin arranged in radial series and those in the center of the semicell in five vertical rows. The vertical view is elliptic with gran- ulate poles. A single protuberance with five granules occurs on each lateral margin. Measurements: L. 28u; w. 28u; I. 9u. Distribution: NLP, Cheboygan (N and A 1932). ERRATA -- Insert on Page 300. 200. Cosmarium punctulatum Breb. West and West, 1908. Monogr. Brit. Desm. 3:206. P1. 84, Figs. 13, 14; Pl. 102, Fig. 22. The semicells of this species are oblong-trapezi- form, with basal angles rounded, and with the convex lateral margin converging slightly to the broadly trun- cate (with straight or slightly convex margin) apex. The semicell wall is granulate, the granules arranged in somewhat irregular vertical and oblique series. The vertical view is elliptic. Measurements: L. 28-40u; w. 27-38u; I. 7.5-l2u. Distribution: SLP, Barry, also St. Clair (N & A 1932); NLP, Crawford, also Emmet (N & A 1932): WUP, Gogebic. 199. 201. Cosmarium Boeckii Wille West and West, 1908. Monogr. Brit. Desm. 3:234. P1. 86, Figs. 26-32. The trapeziform-semicircular semicells of this species have convex lateral margins which are 4-5 crenate. Each crenation is usually entire but dentate, occasionally the lower and upper are emarginate. The apical margin is undulate-crenate. Within the margins there are about twelve relatively large granules arranged in two series. The central region of the semicell is occupied by a ‘ broad but slight protuberance, which is ornamented by five or six diversely arranged granules, the lower gran- ule above the isthmus usually larger than the others. The vertical view is elliptic with granulate poles and slightly tumid tri-granulate lateral margins. Measurements: L. 28-40u; w. 27-38u; I. 7.5-12u. Distribution: SLP, Barry, also St. Clair (N and A 1932); NLP, Crawford, also Emmet (N and A 1932); WUP, Gogebic. var. subpunctulatum (Nordst.) Boerg. fest and west, 1908. Menogr. Brit. Desm. 3:209. P1. 8a, Figs. 15-20; P1. 85, Figs. 1-3. This variety is separated from the typical by the presence of central protuberance in each semicell, upon which the granules may be more or less regularly arranged.‘ Measurements: L. 24—(28)-(32)-36u; w. 23-(26)-(30)-36u; I. (6.5)-7-(7)-16u. 301 Distribution: SLP, Barry (2), Livingston, Washtenaw, Jackson; NLP, Crawford, Roscommon, Presque Isle, also Cheboygan (N and A 1932); EUP, Alger, Schoolcraft; wUP, Marquette, Menominee, Houghton, Gogebic. 202. Cosmarium cruciatum Breb. Wolle, 1892. Desme of the U.S.3 89. P1. 21, Figs. 23,2#. 4 This small species has deeply constricted cells with the sinus narrow and enlarged outwardly. The semi- cells are trapezoid-reniform (truncate-pyramidate) with the lateral margins convergent to the truncate apices. The margins are slightly crenate and the semdcell wall is finely granulate or punctate. The vertical view is elliptic, with a small submamillate protuberance in the middle of each lateral margin. West and West (1912) be- lieve that this species is synonomous with some form of g, punctulatum Breb. The writer has seen no Specimens that agree with this description. Measurements: L. 22-24; W. 22-24u. Distribution: SLP, Wayne (Campbell 1886). 203. Cosmarium anisochondrum Nordst. West and West, 1908. Monogr. Brit. Desm. 3:212, P1. 85, Fig. 5. The subsemicircular (trapeziform-semicircular) semi- cells have convex lateral margins converging upwardly to the truncate apices. The lateral margins are ornamented with seven or eight granules, whereas the apical margins 302 are smooth. Within the lateral margins there are several rows of granules, within the apical margin a single row, The central region of the semicell wall possesses several slightly curved or irregular transverse rows of granules. The vertical view is elliptic with 3-4 large granules on each lateral margin and with the rest of semicell granu- late except for the middle part. Specimens from Oakland County had slightly elevated apices. Measurements: L. 28-30-(34)-u; W. 25-27-(28)u;15.3-(6.5)- 9.5u. Distribution: SLP, Oakland, also Macomb (Johnson 1894). 204. Cosmarium calcareum Wittr. West and West, 1908. Monogr. Brit. Desm. 3:235. P1. 87, Figs. 1, 2. The trapeziform-semicircular semicells have convex lateral margins that have four minute crenulations in the lower part and a single emarginate crenation above. The apices are truncate, and minutely 6-7 crenulate. Granular ornamentation consists of several radiating series of minute granules extending from margin to the central region of the semicell where 8-ll peripheral granules surround 1-4 central ones. The vertical view is elliptic with a granulate (3-4) tumor in the middle of each lateral margin. - Measurements: L. 78-30u; W. 17—27u; I. 5-7.2u. Distribution: NLP, Cheboygan (N and A 1932, Welch 1933a‘ Emmet, (N and A 1932). 303 205. Cosmarium sexnotatum var. tristriatum (Luetkm) Schmidle. P1. 19, Fig. 6. West and West, 1908. ionogr. Brit. Desm. 3:223. P1. 87, Figs. 8, 9. This small organism has truncate-pyramidate semi- cells. The lateral margins of the semicells are convex, 4-5 undulate and slightly convergent to the apical margin which is undulate or almost straight. Granular ornamen- tation on the semicell wall consists of two series within the lateral margin. In addition, there are three elongated central granules each of which are divided into short and a long part. The vertical view is elliptic with three granules in the middle of each lateral margin. Measurements: L. lG-(19)e26u; w. 14-(15)-22u; I. 4-4.5-8u. Distribution: SLP, Calhoun. New record for Michigan. 206. Cosmarium crenatum Ralfs. West and West, 1912. Monogr. Brit. Desm. 4:35. P1. 98, Figs. 9-12. The pyramidate-quadrate semicells or this Species have margins that are crenate (3-4 on lateral, 4 on apical). Within each marginal crenation there are several smaller secondary crenations that are smooth or ornamented with one or two minute granules. Three to six vertical costae (ridges) occupy the center. The elliptic vertical view shows a broad 3-6 undulate inflation on each lateral mar- gin and subtruncate,finely granulate poles. Measurements: L. 27-(28)-43u (rarely up to 59u); W. (21.5)- (22)-3lu (rarely to 44u); I. (6.5)-9-l3u. Distribution: SLP, Barry; NLP, Cheboygan, Emmet (N and A 1932); Isle Royale (Prescott 1937, 1938). 207. Cosmarium modestum Wcst and West West and West, 1898. flour. Linn. Soc. Bot., 33:304. P1. 17, Fig. 12. ‘ The semicells of this species are pyramidate-trap- eziform with rectangular basal angles, convex lateral margins (each with four crenations) and truncate apices (very slightly emarginate). The semicell wall is orna- mented with small granules arranged in concentric and radiating series. The vertical view is elliptic with a central protuberance upon each lateral margin. Measurements: L. 21.4-33u; W. 19.5-26u; I. 5-8-7u. Distribution: SLP, Washtenaw (West and West 1898); Isle Royale (Prescott 1938). 208. Cosmarium subcrenatum Hantzsch. West and West, 1908. Monogr. Brit. Desm. 3:228. P1. 86, Figs. 10-14. The truncate-pyramidate (subsemicircular with a truncate apex) semicells have crenate (4-6) lateral mar- gins which converge to the truncate apices which are 4-5 crenate. Each crenation is ornamented with minute gran- ules. Within the marginal crenations there are one or two series of minute granules concentrically and radially arranged. The central area of the semicell wall is oc- cupied by a broad, slightly elevated protuberance upon Ht 305 which there are 4-Y vertical series of small granules (3-6 granules in each series). The vertical View is elliptic with a broad granulate protuberance on each lateral margin and with rounded or truncate poles. ieasurements: L. 23-(32)-(34)-37u; w. 18-(26)-(30)-32u; I. 7-(10)-16u. Distribution: SLP, Calhoun, Washtenaw; also Macomb (Pie- ters 1894); WUP, Dickinson (N and A 1932); Isle Royale (Prescott 1933)., 209. Cosmarium subprotumidum Nordst. West and west, 1908. Monogr. Brit. Desm. 3:231. P1. 87, Figs. 19-21. This Species has trapeziform-subsemicircular semi- cells. The basal lateral margins are perpendicular to base and are biundulate’and the upper lateral margins are convergent (with a crenation between two hollows) to the apex which is truncate and 2-# undulate. The gran- ular ornamentation consists of one or two series of paired (single inwardly) granules within each marginal crenation and a central tumor with 3-4 vertical series (outer series sometimes slightly curved) of granules with 4-5 granules in each series. The vertical view is elliptic with a broad-threeécrenulate tumor on each lateral margin. Measurements: L. 24-30u; W. 22-27u; I. 6-lOu. Distribution: NLP, Cheboygan (N and A 1932, Neal 1948). 210. -ggsmarium.gpstatum Nordst. West and West, 1908. Monogr. Brit. Desm. 3:239. P1. 87, Figs. 13-16. 306 The semicells of this species are subtrapeziform with convergent lateral margins. The lower lateral mar- gins have one or two small and entire crenations, the up- per lateral margins 2-3 emarginate crenations. The apex is truncate and possesses four emarginate crenations. Within the lateral margins small paired granules (single, inwardly) are arranged in radiating and concentric series. The central region of the semicell is ornamented with 5-7 vertical granular ridges. The elliptic vertical view shows a broad crenulate inflation upon each lateral margin. Measurements: L. 27-57u; w. 25-39.6u; I. 10.5-21u. Distribution: Isle Royale (Prescott 1938). 211. Cosmarium subcostatum Nordst West and West, 1908. Monogr. Brit. Desm. 3:236. P1. 87, Figs. 3-5. The semicells of this species are subtrapeziform- reniform. The convex lateral margins possess 6-7 cre- nations, of which the lower 2 or 3 are entire and the upper are emarginate. The apices are slightly produced and slightly undulate. Within each marginal crenation or undulation there are 2-# series of paired granules (single in innermost series) radially and concentrically arranged. The central area of the semicell (surrounded by a small clear area) possesses a broad tumor upon which there are 4-5 subvertical series of granules (each series with about four granules). 307 Measurements: L. 24.6-(30)-38u; w. 23-(25)-#3u; I. 6.4-(6.4)-12u. ' Distribution: NLP, Presque Isle, also Emmet (Transeau 1917, N and A 1932). 212. fa. EEEQE. West and West. West and west, 1908. Monogr. Brit. Desm. 4:238. P1. 87, This form is separated from the typical by the smaller size and the presence of only 2-3 emarginate crenations. A specimen from Barry County agrees well with the des- cription of this form except for the central tumor which has about nine peripheral granules around a single cen- tral granule andaslightly smaller width. Measurements: L. l9-(l9)-(22)-24u; w. (15)-(17)-18.5-21u; I. 4.2-(5)-5.5u. Distribution: SLP, Barry, also Macomb (Johnson 1894, g, calcareum); NLP, Cheboygan (N and A 1932); WUP, Menominee. 213. Cosmarium norvegicum Stront P1. 19, Fig. 7. Taylor, 1934. Pap. Mich. Acad. Sci.,Arts and Letters, 19:258. P1. 53, Fig. 3. This small species has truncate-pyramidate (pyrami- date sub-semicircular) semicells. Each of the convex lateral margins has 3 or 4 crenations whereas the apical margins possess two crenations and two middle undulations. The intramarginal ornamentation consists of several con- centric series of small granules opposite each marginal 308 crenation or undulation, the outer series with paired granules, the inner series with single granules. The central region of the semicell wall has 3-5 vertical series of granules, usually 3-4 granules in each series. The vertical view is elliptic, with a granulate protu- berance on each lateral margin and with several trans- verse rows of granules. Measurements: L. (24)-24u; W. (22)-22u; I. (4.4)-6.5u. Distribution: SLP, Calhoun, Barry. New records for Michigan. 214. Cosmarium nasutum Nordst. West and West, 1908. Monogr. Brit. Desm., 3:25 . P1. 90, Figs. 9-10. The trapeziform-semi-circular semicells of this species have convergent lateral margins that are slightly convex and sharply crenate (three per lateral margin). The apical margin has two crenations, each of which are 3-4 granulate (almost subpapillate), whereas the crena- tions on the lateral margins are bigranulate. Granular ornamentation within the margins consists of several con— centric radiating series of paired granules (inner often single). The central region of semicell has a tumor which is smooth except for an emarginate granule Just above the isthmus. The vertical view is elliptic with single small lateral protuberances and with transverse rows of granules upon the poles (smooth in center). Measurements: L. 35-42u; W. 28-33u; I. 8.5-l3u. Distribution: NLP, Cheboygan (Taft 1939). 215. Cosmarium binum Nordst. P1. 19, Fig. 5. West and West, 1908. Monogr. Brit. Desm. 3:246. P1. 88, Figs. lO-lfl. The semicells of this species are pyramidate-trapezi— form with convex lateral margins and truncate apices. The margins are crenate (6-10 in lateral, 4-6 in apical), the crenations bigranulate and more or less emarginate. The intramarginal ornamentation consists of radial and concentric series of paired granules (innermost single). The central region of the semicell has a tumor upon which there are located 6-8 granular ridges, and beneath each ridge a single granule. The vertical view is elliptic with a broad granulate central protuberance upon each lateral margin, and with transverse rows of granules ex- cept in center of semicell. Measurements: L. #l-(62 -90u; W. 30-(42)-59u; I. 12-(18)-2lu. Distribution: SLP, Oakland; NLP, Presque Isle; EUP, Schoolcraft. New record for Michigan. 216. Cosmarium subspeciosum Nordst. West and West, 1908. Monogr. Brit. Desm. 3:252. P1. 89, Fig. 11. This species has pyramidate-subsemicircular semi- cells with convex lateral margins which are slightly 310 divergent near base and then strongly convergent above to the subtruncate apices. The margins are crenate (four apical, 6-7 on each lateral) with each crenation bigran- ulate except those at basal angles. Intramargi.al orna- mentation consists of concentric and radial series of minute granules (granules, in outer series, paired, in inner series single). The central region of the semi- cell possesses a tumor upon which are arranged 5-6 some- what irregularly subvertical series of granules. The elliptic semicells in vertical view have broad lateral protuberances and rounded poles. CD Measurements: L. 41—58u; W. 2 .8-43.9u; I. l2-l6.2u. Distribution: SLP, Macomb (Johnson, 1894); Isle Royale (Prescott 1938). 217. var. XEEEEBE. Nordst. West and West, 1908. Monogr. Brit. Desm. 3:253. P1. 81, Figs. 12-13. This variety is separated from the typical by the larger size and the 7-9 vertical series of granules in the central region of the semicell. Measurements: L. 62-85u; w. 47-53u; I. 17.5—22u. Distribution: SLP, Washtenaw (Johnson 1895). 218. Cosmarium supraspeciosum Wolle. Wolle, 1892. Desm. of the U.S.:95. P1. 61, Figs. 5-9. This species has truncate pyramidate semicells. The convex lateral margins and the flattened apical margins are crenate (each of the former with about sixteen and 219. 311 each of the latter with 4-5 crenations). The intramar- ginal ornamentation consists of large undivided granules arranged in concentric and radial series extending about half-way to the central region which is smooth except for 5-6 vertical series of smaller granules. The vertical view is elliptic with a granulate central protuberance on each lateral margin. Measurements: L.9Q-95u; w. 65-70u. Distribution: Washtenaw (Johnson 189”). Cosmarium speciosum Lund. West and West, 1908. Monogr. Brit. Desm., 3:247. P1. 89, Figs. 1-3. The semicells of this species are truncate pyrami- date (almost subrectangular). The lateral margins, which possess about seven crenations, converge very gradually and slightly to the truncate apices, each of which has four crenations. The intramarginal granules are arranged in regular concentric and radial series (about four gran- ules in each radial series). The lower part of the semi- cell just above the isthmus has 6-9 vertical series of granules with about 4-5 granules in each series. The vertical view is elliptic with granules arranged in curved transverse rows. Measurements: L. #8-(51)-64u; w. 31-(38)-4l; I. l4-(2l)-26u. Distribution: NLP, Emmet, also Cheboygan (N and A 1932). U.) H [D 220. var. simplex Nordst. West and West, 1908. Monogr. Brit. Desm., 3:250. P1. 89, Fig. 6. The semicells of this variety have more attenuated lateral margins than the typical. The vertical series of granules at the base of the semicell is usually in- distinct or absent. Measurements: L. 42-60u; W. 26.5-40u. Distribution: Isle Royale (Prescott 1937). 221. var. simplex fa. intermedia Wille West and West, 1908. Monogr. Brit. Desm. 3:251. P1. 89, Fig. 7. ' This form is slightly smaller than var. simplex Nordst. Measurements: L. 38-#Ou; W. 27-29u; I. 14-2lu. Distribution: Isle Royale (Prescott 1938). 222. var. Rostafinskii fa. americana West and West. West and West, 1898. Jour. Linn. Soc. Bot. 33:279. P1. 17, Fig. 13- This form is distinguished from the typical species and from var. Rostafinski (Gutw.) West and West by the lack of vertical series of granules in the lower central region of the semicell wall. It resembles var. simplex Nordst. but the semicell is more pyramidate and the size is smaller. Measurements: L. 40.5u; W. 26.6u; I. 17.2u. Distribution: Isle Royale (Prescott 1938). 223. Cosmarium decoratum West and West West and West, 1895. Trans. Linn. Soc. Bot. Ser. 2, 5:61. P1. 7, Fig. 21. This species has truncate—pyramidate semicells with the slightly convex lateral margins converging gradually to the flattened apices. The semicell wall is ornamented with triangular thickenings, six of which surround a single scrobiculation. The semicell wall thus appears to have a reticulate network composed of linear grooves with a coarse scrobiculation at each intersection. The vertical View is elliptic (almost rhomboid) with tumid lateral margins, and with the same wall decoration as described above. Measurements: L. 70-86u; W. 52-63u; I. 23-32.5u. Distribution: NLP, Cheboygan (Taft 1939). 224. Cosmarium ochthodes Nordst. West and West, 1912. Monogr. Brit. Desm. #:10. P1. 98, Figs. l-3. This species has truncate-pyramidate semicells (ovate- pyramidate from a flat base) with convex lateral margins converging to a narrow and truncate apices. The lateral margins are crenate or undulate (ll—13 per semicell). The intramarginal granulation consists of irregular radial and concentric series which become reduced or are com- pletely lacking in the middle of the semicell. The semi— cell wall is also punctulate. Ieasurements: L. TO-(82)-94u; W. 51-(62)-67u; I. 17.5-(21.5)-2Tu. Distribution: NLP, Cheboygan (N and A 1932); EUP, Delta, Isle Royale (Prescott 1938). 225. var. amoebum West. West and West, 1912. Monogr. Brit. Desm. 4:11. P1. 98, Figs. 4-6. This variety is separated from the typical by the pyramidate-trapeziform semicells (broader apices), the very much depressed granules which are sinuate in outline and the faintly undulate margin. Measurements: L. 82-(87)-ll3u; W. (54)-60-75u; I. l9-24u. Distribution: SLP, Barry, Oakland; Isle Royale (Prescott, 1937, 1938). 226. var. Novae-terrae Taylor. nob. P1. 20, Fig. 2. Taylor, 1934. Pap. Mich. Acad. Sci., Arts and Letters, 19:258, P1. 52, Fig. 8. This variety which was unnamed by Taylor (1934) has) somewhat shorter and more stout semicells which are py- ramidate-truncate (to sub-semicircular) in outline. The convex lateral margins are slightly crenate and the api- cal margins are straight or slightly undulate- The in- tramarginal ornamentation consists of 3-5 crenations rad- ially arranged within each marginal crenation (about 7-9' per lateral margin} The intramarginal crenations are lacking within the apices. The semicell wall is closely 315 and densely punctulate, the punctae in the polar areas forming blocks of transverse rows. The vertical view is elliptic with crenate poles and with the cell wall punc- tate as described above. Specimens from Barry and Shia- wassee Counties are assigned here although neither the polar punctation nor the scrobiculate semicell wall in the Shiawassee County specimens agree with typical char- acteristics. They should be compared with var. subcir— culare Wille which has uniformly undulate margins and a smaller size. Measurements: L. (6#.5)-65-(65)u; W. 50-(50)-(54)u; I. 12-(15)-(17)u. Distribution: SLP, Barry, Shiawassee. New records for Michigan. 227. Cosmarium retusum (Perty) Rab. West and West, 1908. Monogr. Brit. Desm. 3:264. P1. 91, Figs. 1, 2. The semicells of this species have retuse lateral margins converging from broadly rounded basal angles to truncate apices which may be straight or slightly convex. The granular ornamentation consists of 4-8 granules at each basal angle (3 or 4 of which are upon the margin), 3-6 granules irregularly disposed in the center of the semicell, and sometimes 3—h granules in an subapical row. Specimens from Alger, Schoolcraft and Gogebic Counties lack granules in the central region of the semicells. as 316 West and West (1908) state that the granulation is ex- ceedingly variable and not infrequently scarcely visible, the author has included these forms here. Also included is Prescott's (1938) record of g, columbianum G. S. West. Measurements: L. 28-39-(42)u; W. 24-31-(33)u; I. 8-10- (10.5)u. Distribution: EUP, Alger, Schoolcraft; WUP, Gogebic; Isle Royale (Prescott 1938). O H O o / Cosmarium denticulatum fa. Borcei Irenee-Narie * Iréhee-Marie 1938. Ebr. Desm. de la Reg. Mont.:209. P1. 28, Figs. 1 and 3—6; P1. 68, Fig. 4. This organism has truncate-pyramidate semicells with convex lateral margins converging gradually to the trun- cate apices which have straight or slig tly rounded mar- gins. The lateral margins are ornamented with numerous (32-44) wart-like granules and the apical margins are smooth. Within the margins there are 4-5 concentric series of granules similar to those on the margins but diminishing in size inwardly. The base of each semicell above the isthmus is ornamented with 2—4 transverse rows of granules. This latter characteristic distinguishes this species from.g, 93g 3 Ralfs. The semicell wall is finely scrobiculate. Measurements: L. 168—(192)-203u; w. 95-(97)-109u; I. (32)-35-kuu. Distribution: SLP, Barry, Washtenaw, also Calhoun (Pres. and Mag. 1935). ..: .— 317 229. Cosmarium ovale Ralfs. West and West, 1908. Monogr. Brit. Desm. 3:267. P1. 92, Fig. 1; P1. 93, Fig. 1; P1. 94, Fig. 1. This very large species has truncate-pyramidate (ovate from a broad flat base according to the Wests(1908» semicells with the lower lateral margins convex and very slightly convergent and with the upper lateral margins almost straight and convergent to rounded truncate apices. Large conical granules are arranged in series upon or Just within the lateral margins. The apical margin is smooth but with one or two irregular series of granules just within the margin. The cell wall is finely scrobi- culate. The vertical view is elliptic with granules (arranged in 4-5 irregular rows) forming a broad band from pole to pole. Measurements: l66-(168)-222u; E. 90-(97)-l36u; I. 30-(30)-48u. Distribution: SLP, Barry (2); NLP, Cheboygan (N and A 1932); EUP, Schoolcraft. 230. var. Prescottii Iréhee-Marie. Iréhee-Marie 1938. Flor. Desm. de la Reg. Mont:208. P1. 68, Figs. 1, 2. This variety is separated from the typical by the presence of one or two transverse rows of granules across the base of the semicell. It resembles C. denticulatum fa. Borgei IreneeéMarie but one or two intramarginal 318 series of granules distinguished it (var. Prescottii) from this form. PO v I [\J H R") :1 \o o .——o Measurements: L. 163-(19 i. 93-(lOY)-llGu; I o (32)-36-4011. Distribution: SLP, Barry; EUP, Houghton; Isle Royale (Prescott 193 , 1938). lfij 231. Cosmarium Gayanum var. eboracense G. S. West. P1. 20, ' '3 lg. Jo West and West, 1912. Monogr. Brit. Desm., 4:3. Fl. 93, Figs. 6-8 (P1. and Figs. in.Vol. 3, 1908). The semicells are truncate-pyramidate (ovate-pyra— midate from a flat base) with convex lateral margins con— verging from rectangular-rounded bases to the truncate apices. Each lateral margin possesses about twenty-four minute granules to which of each there is corresponding series (7-9 granules) radiating inwardly within the mar~ gin. The granules progressively decrease in size inwardly to the central region of the semicell wall which is punc- tate. Measurements: L. 85~(91)-110u; w. 51-(55)-68u; I. (19)-20-22.5u. Distribution: NLP, Roscommon; EUP, Chippewa. New records for Michigan. 932. Cosmarium Botrytis Menegh. West and West, 1912. Monogr. Brit. Desm., 4:1. P1. 96, Figs. 1, 2, 5-15. The semicells of this species are truncate-pyramidate (ovate-pyramidate from a broad flat base according to 319 West and West 1912) with convex lateral margins converging gradually to the narrowly truncate or subtruncate apices. The semicell wall and margin is ornamented with granules either irregularly or in slightly concentric series. The vertical view is elliptic without lateral protuberances. Measurements: L. 60-(83)-lllu; w. 51-(56)-85u; I. 14-(17)—26u. Distribution: SLP, Ionia (Wade 1949), Wayne (campbell 1886), Macomb (Pieters 1894); NLP, Emmet (Transeau 1917 and N and A 1932), Cheboygan (Transeau 1917, Welch 1936a, 1938b)(Neel 1948); WUP, Menominee; Isle Royale (Taylor 1935, Prescott 1937, 1938). 233. var. mediolaeve West. west and west, 1912. Monogr. Brit. Desm., 4:6. P1. 97, Fig. 5. This variety is separated from the typical by the smooth and faintly concave apex, by the intramarginal granules arranged in concentric and radiating series and by the smooth central area of the semicell. Measurements: L. 54.5-70u; W. 47-59u; I. l5-15.5u. Distribution: NLP, Cheboygan (N and A 1932); Isle Royale (Prescott-1938 fa.). 234. var. subtumidum Wittr. fa. Irenee-Marie nob. Pl. 20,Fig. 4. Irenee-Marie, 1938. F10“ Desm. de la Reg. Mont.:211; P10 31, Fig. 143‘P10 32, Figs. 5'60 This organism is separated from the typical by the proportionately wider cells and the larger size of the Q20 d granules in the central region. Specimens from Oakland County agree favorably with Irenee-Marie's (1938) unnamed forma in which some of the intramarginal granules above the central region of the semicell are very strongly de- veloped and a few are emarginate. Measurements: L. 55-(59)-65u; W. 45-47-(59)u; I. lO—l2-l#u. Distribution: SLP, Oakland. New record for Michigan. 235. var. tumidum Wolle. West and West, 1912. Monogr. Brit. Desm. 4:5. P1. 97, Figs. 2, 3. This variety is separated from the typical by the possession of a central tumor on each semicell. The gran- ules on the central tumor are larger than other granules and are irregularly disposed. Occasionally there is a large granule adjacent to the base. 1 Measurements: L. 65-85u; W. 50-68u; I. 17-20u. Distribution: Isle Royale (Prescott 1938). 236. fa. nudum_ fa. nov. P1. 21, Fig. 2. Collections from Menominee County were rich in num- ber of individuals of an organism.which agrees favorably with most characteristics of Q3 Botrytis var. tumidum Wolle. Granules on the central tumor in each semicell were not larger than other granules as in the variety but were either poorly developed or lacking. A large supra- isthmial granule was present on each semicell. This l1." 321 characteristic which is present sometimes in the variety plus the presence of a central protuberance which is characteristic of the variety seem valid proof for desig- nating these organisms as a new form of this variety. Measurements: L. (75)u3 W. (59)u; I. 17u. Distribution: WUP, Menominee. 237. Cosmarium tetraopthalmum Breb. West and West, 1908. Monogr. Brit. Desm. 3:270. P1. 95, Figs. 4-7. This plant has pyramidate-ovate to truncate-pyramidate semicells. The lateral margins are convex and the apical margin flattened and somewhat truncate. The granular ornamentation consists of lO-lh granules along each lat- eral margin (apices smooth). Within the margins, the granules are arranged in concentric and radial series (or more or less scattered according to West and West 1908), becoming very much reduced in size near the middle of the semicells. Measurements: L. 90-120u; W. 60-86u; I. l8-30u. Distribution: NLP, Cheboygan and Emmet (N and A 1932); Isle Royale (Prescott 1937, 1935)- 238. Cosmarium spinosporum Lag. West and West, 1898. Jour. Linn. Soc. 33:309. P1. 17, Fig. 89. Lagerheim, 1887. Ofvers. K. Sv. Vet. Akad. Forh. 8:538. The writer has been unable to obtain the original description of this organism because the Journal is un— available. The only other reference known to the writer is that of West and West (1898) who merely report its occurrence in Washtenaw County. 16. COSMOCLADIUM Breb. 1956 Cells small, round in outline or with length slightly greater than width; medianly constricted and similar in shape to Cosmarium; inclosed in mucilage and united by gelatinous bands into spherical or ellipsoidal few-celled colonies that are attached or free-floating. Semicells subpyramidate, sub- reniform or elliptic in front view, circular or elliptic in transverse view, and subcircular in side view; sometimes with a median facial swelling or tubercle. Chloroplast axial, usually one in each semicell, and each with a central pyrenoid. Zygospores spherical with short spines or broadly angular projections. Key to Species of Cosmocladium 1. Cells with a median facial swelling or tumor . . . . . . . . . . . . . 2 1- Cells without a median facial swell- ing or tumor . . . . . . . . . . . 3 2. Semicells hexagonal elliptic; L. 9u; W. 8u. . . . . . . . . (l) g, tumidum 2. Semicells subreniform; L. 14.5- l5u; W. 11.5—l2u. . . . . . . (2) g, tuberculatum 3. Semicells subpyramidate in front view, circular in transverse view; med- ian constriction very slight . . . (3) g, constrictum 323 3. Semicells oblong-elliptic, elliptic, or subreniform in front view; el- liptic in transverse view; median constriction well defined and linear . . . . . . . . . . . . . 4. Semicells oblong elliptic; length equal to breadth (lO- 12u . . . . . . . . . . . . (5) g, pusillum 4. Semicells elliptic or subreni- _ form; length always somewhat greater than width (10.5)-l2- 24u x (8.5)-ll-l6u . . . . . (4) g, pulchellum 1. Cosmocladium tumidum Johnson Johnson, 1895. Bull. Torr. Bot. Club. 22(7):296. Pl. 240. Fig. 23. This small species has transversely hexagonal-el- liptic semicells, a median facial inflation and is slightly longer than wide. Measurements: L. 9u; w. Bu; I. 2u. Distribution: SLP, Washtenaw (Johnson 1895, N & A 1932). 2. Cosmocladium tuberculatum Prescott Prescott and Magnotta, 1935. Pap. Mich. Acad. Sci. Arts, Letters: 20:163. P1. 25, Fig. 11. This Species has a median facial tubercle, subreni- form semicells, and cells longer than wide. Measurements: L. 14.5-15u; w. ll.5-l2u. Distribution: SLP, Calhoun (Pres. & Mag. 1935). 3. Cosmocladium constrictum Arch. West, West and Carter, 1923. Monogr. Brit. Desm. 5:198. P1. 158, Figs. 1-3. The characteristic subpyramidate semicells (circu- lar in transverse view) and the very slight median con- striction easily distinguishes this Species. Measurements: L. 16-20u; w. lO-l2u; I. 8.5-9u. ‘ Distribution: NLP, Cheboygan (N a A 1932); EUP, School- craft (Transeau 1917). 4. Cosmocladium pulchellum Breb. West, West and Carter, 1923. Monogr. Brit. Desm.:200. Pl. 158, Figs. 11, 12. This species is characterized by elliptic or sub- reniform semicells, with the cells always being longer than wide. Measurements: L. (lO.5)-l2-24; W. (8.5)-11-16u; I. 4-4.5u. Distribution: SLP, Oakland, also Muskegon (Transeau 1917). 5- Cosmocladium pusillum Hilse West, West and Carter, 1923. Monogr. Brit. Desm. 5:201. Pl. 158, Figs. 8-10. This species has elliptic or subreniform semicells and the cell length is always somewhat greater than width. Measurements: L. lO-l2u; w. lO-l2u; I. 2—3u. ' Distribution: Barry, also Calhoun (Pres. & Mag. 1935). 17. ARTHRODESMUS Ehrenb. 1838 Cells relatively small, and as broad as long; usually com- . pressed, and bilaterally symmetrical; in front View the semi- cells generally obversely triangular, more rarely transversely 325 elliptic, subtrapeziform, subrectangular, or subquadrate; med- ian constriction relatively deep with the sinus widely open to linear (closed in g, Bulnheimii); cell wall without ornamenta- tion except for single spines (paired spines at apical angles in in tenuissimus nd 9. trispinatus fa.) inserted at each P angle. Cells in vertical view usually elliptic, rarely fusi- form or triangular, with single spines at pole (one spine on each side near pole in A. tenuissimus, and g, trispinatus fa.). Chloroplast axial, usually one in each semicell; pyrenoids usually single and arranged centrally in each chloroplast. Zygospore smooth or with simple spines. {ey to Species of Arthrodesmus l. Semicells bearing two spines . . . . 6 1. Semicells bearing more than two Spines . O O . . O O O O C O O O O 2 2. Semicells bearing four spines . 3 2. Semicells bearing six spines . 5 3. Semicells hexagonal depressed with . straight sides . i . . . . . . . . (1) £3 biiidus var. truncatus 3. Semicells rectangular, with retuse 4 sides . . . . . . . . . . . . . . 4. Length of cells up to 27u (without Spines . . . . . . (2) octocornis ’w . w" 0 Us 4. Length offitver 30u (without spines); angles extended to A form lobes . . . . . . . . . (3) g. impar Apical angles with minute granular ines, lateral angles with short ines . . . . . . . . . . . . . . (4) \jl S a L.) p p Iv; M (,0 F0 C \ 5. Apical angles with well-defined spines; lateral angles with spines of the same length . . . . (5) A. trisoinatus / 1 o ‘ 1 ‘ o. noex highly elevated and broad- 1y truncate . . . . . . . . . (6) A. michiganensis 6. Apex otherwise . . . . . . . . 7 7. Semicells transversely elliptic . . 8 7. Semicells not transversely elliptic. 9 g) " 1 _' "" r o. spines convergent . . . . . . . (() A. convergens (j . o 1.. -0 J. o. Sp nes horizontal or slightly divergent . . . . . . . . . . (8) A3 subulatus 9- Semicell subrectangular, sinus closed or nearly so at the apex . (10) A, Bulnheimii var. subincus 9. Semicell not subrectangular . . . . 10 10. Spines less than 4u long, usu- ally about 2u . . . . . . . . 11 12 10. Spines more than 4u long . . . 11. Width without spines, 12.9-17u . . . (11) A, grassus 11. Width without spines, 10.5-11.711 . - (12) 1;; var. rasiliense 12. Spines convergent . . . . . . . l3 l2. Spines horizontal or divergent. l4 13. Spines straight . . . . . . . . . . (13) A, Ralfsii 13- Spines twisted . . . . . . . . . . . ( 5) A. crispus var.m;u9r 14. Apex retus . . . . . . . . . . (16) A. ohimus l4. Apex not retuse A H (,0 v | 31* Ho :5 O C (D 15- Apex flat or concave . . . . . . . . 15. Apex slightly elevated, often with a ‘ median indentation . . . . . . . . ( P0 0\ v A. triangularis l. arthrodesmus bifidus var. truncatus West west and west, 1912. Monogr. Brit. Desm. 4:114. Pl. 117, Fig. 14. This small variety is characterized by the subhexa- gonal form with a single minute spines at each angle. Measurements: L. lO-l5.5u; w. 10-14.4u; I. 4.5-5.7u. Distribution: NLP, Cheboygan (N & A 1932). 2. Arthrodesmus octocornis Ehrenb. Nest and West, 1912. Monogr. Brit. Desm. 4:111. Pl. 117, Figs. 6-10. This species characteristically has transversely trapeziform-rectangular semicells, the margins retuse be- tween the angles. It is easily separated from.A, EEEEE (Jacobs) Gronbt by its smaller size, and by the angles not being extended into lobes. Measurements: L. ssp. (l4)-2l.5-24-(27)u; L. csp. (3o)- 30-(42)u; W. ssp. (lO)-l4-(20)u; W. csp. 20-(22)-44u; I. (4)-5.5-(lOu. Distribution: SLP, Berrien, Calhoun; NLP, Emmet, Che- boygan (N & A 1932); EUP, Chippewa, Schoolcraft; WUP, Houghton, Gogebic (2). a. Arthrodesmus impar (Jacobs) Gronbl. P1. 7, Fig. 4. Gronblad, 1921. Acta. Soc. pro Faun. and Flor. Fenn. 49(7):55. P1. 3, Figs. 58-60. This species resembles A, octocornis Ehrenb. super- ficially but is easily separated by its greater size and by the lobes which are formed by the extension of the angles. Measurements: L. ssp. 29.7-(33)-40u; L. csp. 65-(67)-80u; W. ssp. 26.4-(33)-42u; W. CSp. 59.4-(65)-80u; I. lO-(10.5)- 13u. . Distribution: NLP, Roscommon; EUP, Chippewa. New record for Michigan. The only other reports of this species in North America are those of Taylor (1934), for New Found; land and Prescott (1935) for Massachusetts. 4. Arthrodesmus tenuissimus Archer P1. 7, Fig. 5. West and West, 1912. Monogr. Brit. Desm. 4:116, P1. ll7, Figs. 18, 19. This small species can be confused easily with A, 237 figu§_var. truncatus West. The latter, however, bears only four spines on a semicell, whereas A, tenuissimus bears six, four of which are not more than small gran- ules upon the apical angles. ' Measurements: L. 8-(8.5)-lOu; w. ssp., Spines (8.5)- ll.5u; w. csp. (lO)-13.6u; I. (5)-5.5u. Distribution: WUP, Houghton. New record for Michigan. 5. Arthrodesmus trispinatus West and West P1. 7, Fig. 6. West and West, 1912. MonOgr. Brit. Desm. 4:115. P1. 117, Fig. 17. The typical form of this species shows’in vertical view, three superimposed spines at each pole. The speci- mens examined from Barry County show three spines at each 329 pole not superimposed. The typical form in front view has three equal undulations on each lateral margin with a spine on each crest. The Barry County specimens have, on each side, one spine inserted upon each lateral angle, and two Spines inserted on the apical angles. These agree well with forms shown by Skuja (1928). The equal size of the spines and the shape of the semicells easily distingu- ish this form from £3 tenuissimus Archer. This should also be compared with Xanthidium Smithii Arch. Measurements: L. ssp. (lO.5)-11.5u; L. csp. 17-(19)u; W. ssp. (8)—llu; W. opp. 17-(17)u; I. (4.5)-6.2u. Distribution: SLP, Barry. New record for North America. 6. Arthrodesmus_michiganensis Johnson Johnson, 1395. Bull. Torr. Bot. Club. 22(7):296. Pl. 239, Fig. 12. The elevated truncate apex separates this species from others. Specimens from Barry County are proportion- ately narrower than Johnson original figures, and agree I more favorably with those illustrated by Smith (1924). Measurements: L. (32)-26-40u; W. ssp. (22)-24-30u; W. CSp. (44)-65u; I. 5.5-(8.5)-9u. Distribution: SLP, Barry, Oakland, also Washtenaw (John- son 1895). This alga is quite rare, having been reported only from Wisconsin (Smith 1924), Michigan and New York, (Burkholder 1931). 7. firthrodesmus convergens Ehrenb. West and West, 1912. Monogr. Brit. Desm. 4:106. Pl. 116, Figs. 4-13. The transversely elliptic semicells with convergent spines on each lateral margin easily distinguish this species, although there is some variation in form of semicells, and in the length of the spines. Measurements: L. 33-(38)-54u; W. ssp. (38)-40-64u; W. csp. 50-(64)-90u; I. lO-(ll)-17u. Distribution: Well represented in the writer's collec- tion. SLP, Calhoun, Barry (2), Washtenaw, Berrien, also Washtenaw (West and West 1898); NLP, Emmet, Crawford, also Cheboygan (N & A 1932); EUP, Chippewa, Alger, Schoolcraft; WUP, Marquette, Houghton. 8. Arthrodesmus subulatus Kuetz. West and West, 1912. Monogr. Brit. Desm.4:109. P1. 16, Fig. 14; P1. 117, Fig. 1. The elliptic obsemicircular shape of the semicells and the elevated apices characterize this species. Measurements: L. 27-50u; W. ssp. 18-54u; W. csp. 52-100u; I. 6—13.5u. Distribution: SLP, Berrien; NLP, Cheboygan (N & A 1932, Welch 1938a); EUP, Schoolcraft. 9. var. subaequalis West and West west and West, 1912. Monogr. Brit. Desm. 4:110. Pl. 117, Figs. 2, 3. This variety has a greater proportionate width of. the semicells and less difference in convexity between the upper and lower margins of the semicells when compared U.) U) H with the typical plants. The only specimens that the writer has examined appear somewhat intermediate between the typical and var. subaequalis but are placed in the latter category because of the similar convexity of the dorsal and ventral margins of the semicells, although the measurements are closer to those of the typical. This intermediate form approaches very closely the organism figured by Iréhee-Marie (1938) as the typical plant. Measurements: L. (28)-31-38u; W. csp. (27)-31-42u; W. csp. (47)-52-C5u; I. (6)-8-l2u. Distribution: NLP, Presque Isle, also Cheboygan (N &_A 1932). 10. Arthrodesmus Bulnheimii var. subincus West and West West and West, 1912. Monogr. Brit. Desm. 4:105. P1. 116, Fig. 3. The distinguishing features of 5: Bulnheimii are the subrectangular shape of the semicells, and the closed linear sinus, Smith (1924); however, does not recognize the latter as being characteristic of Wisconsin forms, nor do his figures indicate such a condition. The writer has observed specimens from several counties which show either a closed or a slightly closed sinus, but which must be designated as var. subincus because of the rounded basal angles of the semicells. These specimens are larger than those reported by Taylor (1934) from New Foundland or by West and West (1912) from Great Britain. 33C Measurements: L. ssp. 23—(33)-28-(36)u; L. csp. 44-54- (56)u; W. ssp. 24-(29)-28-(;5.5)u; W. csp. 45-(52)-54- (57)u; I. 4.5-8-(8.5)u. Distribution: NLP, Emmet, also Cheboygan (Taft 1939); EUP, Schoolcraft. . ll. Arthrodesmus crassus West and West fa. Borge Pl. 7, Fig. 7. Borge, 1930. Arkiv. f. Botanik. 23A(2):40. P1. 2, Fig. 36. West and West, 1912. Monogr. Brit. Desm. 4:102. Pl. 115, Figs. 8, 11. There is some difficulty in determining the limits of A. crassus and A. controversus. West and test (1912), who are the authors of both species, separates them on the basis of size and the shape of the semicell in ver- tical view. é, crassus has a length of 19.5-24u; and is broadly elliptic-fusiform (West and West use the term rhomboid in their analytical key) in vertical view. A. controversus is much smaller, being 10.5—12u long, and is broadly elliptic in vertical view. Borge (1930) des- cribed a new form which he places in g, crassus (probably upon the basis of the appearance in front view). This form however, has a length of 14.3-16u (intermediate be- tween A. crassus and g. controversus), and the broadly elliptic shape of g, controversus in vertical View. The shape of specimens from Berrien County are closer to Borge's form than to either of the typical plants of both species, although the measurements are closer to a. contro- versus. Perhaps both Borge's form and the Berrien County 333 specimens could be better considered forms of g, contro- versus than of g, crassus. Measurements: L. (l2.9)-14.3-16u; W. ssp. (l2.9)-l4-17u; w. csp. (15)-15.5-20u; I.(6.5)-7-8.5u. Distribution: SLP, Berrien. New record for North America. 12. Arthrodesmus controversus var. brasiliense Borge. Pl. 7, Fig. 8. Borge, 1918. Ark. r. Bot. 15(13):40. Pl. 2, Fig. 21. West and West, 1912. Monogr. Brit. Desm. 4:103. Pl. 115, Figs. 12, 14. The characteristics of both 5, controversus and g, crassus were mentioned previously under §, crassus. Borge (1918) described the variety brasiliense from Sao Paulo, Brazil as a slightly larger form.with a less ro- tund apex. The writer has observed specimens from School- craft County that are similar to this variety in shape and measurements. These Specimens differ from the var— iety, however, by having a slight retuseness in the median portion of the apex. The lateral view compares favorably with .t_\_. crassus fa. Zachariasii Gronb. (= 1_\_._ Zachariasii Schroder) (see Gronb. 1926), which is prob- ably identical with 53 controversus var. brasiliense although no measurements are given. Measurements: L. l2-(l2.9)-14.5u; W. ssp. 10.5-11.5- (ll.7)u; W. csp. 13.5-(14.9)-l6.5u; I. (6.5)-7-8u. Distribution: EUP, Schoolcraft. New record for North America. l4. 15. Arthrodesmus Ralfsii W. West West and West, 1912. Monogr. Brit. Desm. 4:95. Pl. 114, Figs. 2-4. West originally described this species, and later transferred it to g; ingu§_as a variety. The writer follows Smith (1924a) in considering this alga a distinct species. The most distinctive character is the conver- gent spines. In addition to this, the length-width ratio separates it from g, ingg§_(Breb.) Hass. Measurements: L. l6-33u; W. ssp. 16-20u; W. csp. 28-47u; I. 7.5-8.5u. Distribution: NLP, Cheboygan (N & A 1932). var. Brebissonii (Racib.). Smith Pl. 8, Fig. 2. Smith, 1924. Wisc. Geo. Nat. Hist. Surv. Bull. 57(2):l30. P1. 85, Figs. 13-17. This variety is separated from the typical by the triangular semicells, the greater length, and the degree of convergence of the spines. Measurements: L. (19)-21-27u; W- 889- (19)—25u; w. csp. (43)-47-60u; I. (4.5)- Distribution: NLP, Presque Isle. New record for Michigan. Arthrodesmus crispus Turner var. minor var. nov. Pl. 8, Fig. 1. Cells small, median constriction moderately deep, sinus widely open and with a rounded apex. Isthmus nar- row and elongate, semicells obversely subtriangular with 335 convex sides and very slightly convex apices which are somewhat retuse in the median part. Upper angles with fairly long spines that are convergent and slightly twisted. Vertical view elliptic with each pole armed with a long, slightly twisted spine. Nordstedt (1895) transfers 5, crispus, g, curvatus, and g, gangensi§_(all described by Turner 1892) to 5, 5327 berulus Joshua. This transfer, however, has not been held valid, or at least recognized, by several authors (GronbL 1921, Krieger 1932). Although the writer has been unable to locate any descriptions of g, rispus or £3 gangensis, other than the original descriptions of Turner (1892), a variety of g, curvatus has been des- cribed by GronbL (1921). It is the writer‘s opinion that &, crispus must be considered a valid Species (at least distinct from.g, gibberulusl because it differs from.§, gibberulus in the lack of lateral inflations in vertical view, in the less elevated apices, and in the more slender spines. The Michigan specimens differ from the typical in the smaller size, the presence of a more elongated isthmus, broadly open sinuses, and less convergent spines. g3 curvatus and g3 ggngensis Turner, are at least closely related forms, and probably are identical with.§3 crispus. Measurements: L. 30u; W. ssp. 29u; W. csp. 59u; I. 8.3u. Distribution: WUP, Gogebic. 16. 17. 18. 336 Arthrodesmus phimus Turner Turner, 1892. Kongl. Sv. Vet. Akad. Handl. 25(5):136. P1. 12, Fig. 9. This species is distinguished by the marked concavity of the apex of the semicell. Measurements: L. csp. 19.5-26u; L. csp. 36u; W. ssp. 20-35u; W. csp. 42u; I. 6.5-7.6u.‘ Distribution: NLP, Cheboygan (Taft 1939). var. occidentalis West and West West and West, 1912. Monogr. Brit. Desm. 4:104. Pl. 115, Fig. 17. This variety is smaller than typical, with cells broader than long. The sinus is less open and the angles are less produced. The writer's specimens from.Boscommon County agree with measurements of the variety very closely, except for the presence of longer spines whiCh, on the other hand, are characteristic of the typical. Measurements: L. (14)-l4-14.6; W. ssp. 16.3-(17)-17.3u; w; csp. 19-19.4u£30u); I. (5)-5.7-6.2u. Distribution: INLP, Roscommon, also Cheboygan (Taft 1939). Arthrodesmus incus (Breb.) Hass. West and West, 1912. Monogr. Brit. Desm. 4:90. P1. 113, Figs. 13-15. Smith (1924), and West and West (1912), consider the typical g, incus of the early investigators as follows: 337 (cell about as long as broad, semicells obversely tri- angular with a straight or slightly convex apex, narrow isthmus, broadly open sinus with an acute apex, acute angles bearing long divergent or subparallel spines, ver~ tical view elliptical. Numerous varieties and forms have been described in the past, making it difficult to de- limit the exact form of this species. Measurements: L. ssp. 21-27u; L. csp. 27-50u; W. ssp. 18-26u; W. csp. 56-7lu; W. 7-9u. Distribution: SLP, Berrien; NLP, Cheboygan (N & A 1932, Welch 1936b). 19- forma isthmosa Heimerl. Heimerl, 1891. Ver. x. K. 2001. Bot. Ges. 41:603. Pl. 5, Fig. 18. A small variety characterized by a narrow trapezi- form semicells with angular bases, widely open sinuses, semicircular apices and horizontal to slightly diver- gent spines. The vertical view is fusiform. There is a resemblance to the variety extensus from which it differs primarily in the presence of a shorter isthmus, and a greater breadth to length ratio. Measurements: L. 13-18-(19)u; W. l3-29u; W. csp. 32H; I. (5)-6n. Distribution: SLP, Calhoun; NLP, Cheboygan (N a A 1932). 20. forma M West and West West and‘West, 1912. Monogr. Brit. Desm, 4:92. Pl. 113, Figs. 16-19. 338 A small variety about 1/2 the size of the typical, with the semicells slightly inflated. Measurements: L. ssp. 12.5-16.5; L. csp. l9-25u; W. ssp. 12.5-13.5u; W. csp. l9-26u; I. 5.5-7. Distribution: NLP, Cheboygan (N'& A 1932). 21. forma semilunaris Schmidle Pl. 7, Fig. 10. Schmidle, 1895. Cest. Bot. Zeit. 45: P1. 16, Fig. 9. A small variety characterized by the decidedly con- vex apex of the semicell, the broadly open sinus with an acute apex, and the acute angles terminated by sharply divergent spines. Measurements: L. ssp. (13)-u; L. csp. (19.5)u; W. ssp. 10.5u; W. csp. 15.2u; I. 5.3u. Distribution: WUP, Chippewa. New record for North America. 22. fa. triquetra West and West West and West, 1912. Monogr. Brit. Desm. 4:99. Pl. 118, Fig. 16. This variety is triangular in vertical view, and has retusa sides. Measurements: L. ssp. 21u; W. ssp. 2lu; W. csp. 48u; I. 6.5u. ' Distribution: SLP, Muskegon (Transeau 1917). 23. var. extensus Anderstn Smith, 1924. Wis. Geo. a Nat. Hist. Surv. Bull. 57(2):132. P1. 85, Figs. 23-26. It»: 339 This variety is characterized by the trapeziform shape of the semicells and the elongate isthmus. It should be compared with fa. isthmosa from.which it dif- fers in a greater breadth-length ratio, and a more elon- gate isthmus. Measurements: L. 20-(23.5)-25; W. ssp. lS-lTu; W. csp. 45362u: I. 5-6-(7.5)u. Distribution: SLP, Berrien; NLP, Schoolcraft; WUP, Goge- bic; Isle Royale (Prescott 1937);, triangularis var., 1940; A, triangularis var. inflatus West and West). 24. var. indentatus West and West West and‘West, 1912. Monogr. Brit. Desm. 4:94. Pl. 113, Figs. 20-24. The slight constriction of the basal part semicell Just above the isthmus is the distinctive feature of this variety. It results in a transversely rectangular por- tion of the upper half of the semicell, and a cup-shaped portion in the lower half of the semicell. The spines are usually divergent but may rarely be horizontal. The latter characteristic is present in specimens from Cal- houn County; These specimens are also slightly smaller in width of semicell and isthmus than measurements given in West and West, (1912). Measurements: L. 18-(21.8)-22u;'W. ssp. (lS.2)-18-22u; W. cap. 35-(43.6)-48u; W. (4.3)-7-9u. Distribution: SLP, Calhoun: NLP, Cheboygan (N & A 1932). 340 25. var. longspina Eichl. and Racib. Pl. 7, Fig. 9. Eichler and Racib., 1893. Akad. LLmieJ. w. Krakow. 2 Ser. 6:120. Pl. 3, Fig. 21. A small variety which is characterized by its size, slight retuseness of apex of semicells and the sharply diverging long spines. The figure used by West and West (1912) to illustrate this variety lacks the retuse char- acter of the semicell apex. The measurements are slightly smaller than the British forms. Measurements: L. ssp. (ll)-l4u; L. csp. (18.5)u; W. sap. (8.8)-ll.5u; W. csp. (18.5)u; I. (4.5)u. Distribution: SLP, Ingham. New record for North America. 26. Arthrodesmus triangularis Lagerheim P1. 7, Fig. 10. Lagerheim, 1885. Ofvers. Kgl. Sv. Vet..Akad. Forh. 42(7):244. P1. 27, Fig. 22. The distinguishing features of this species are the obversely triangular semicells with shallow retuseness of the slightly elevated apex, the widely open sinus with bluntly flattened apex, and the narrow and elongate is- thmus. Specimens from Calhoun County have measurements in the lower range for the species. Measurements: L. 15-(17-4)-30u; W. ssp. 14-(15)-25u; w. esp. (34)-52-65u; I. (4.3)-5-7u. Distribution: SLP, Calhoun. New record for Michigan. 27- var. rotundatus (Racib.) Smith Smith, 1924. Wise. Geo. a Nat. Hist. Surv. Bull. 57(2): 133. P1. 86, Figs. 2-u. ‘ 341 Smith has combined var. inflatus of West and'West, and Raciborski's var. rotundata. These forms are dis- tinguished from the typical by the larger size, and the more convex apex of the semicells inXWhich the median indentation may be reduced or wanting. The semicells are angular-elliptic in shape,ibeing slightly inflated in appearance. This form approaches A, subulatus fa. americana (Turner) West and West, from.which it differs in the more elongated and narrower isthmus, the narrower elliptic semicell in vertical view, and the slightly smaller maximum.width. Specimens observed from Barry County are wider than measurements given by West and West (1912) or Smith (1924), but otherwise agree with the description of fa. rotundatus. Prescott's figures of A, triangularis Lag. var. (1937) and of A, triangularis var. inflatus (1940) do not appear to belong to this form. Measurements: L. 24-(33)-38u; W- BSD. 19-25-(31)u; W. csp. 57-(62)-76u; I. 5.8-(7)-7.5u. ' Distribution: SLP, Barry; NLP, Cheboygan (Taft 1939, A, incus var. inflatus). 18. SPINOCOSMARIUM Prescott and Scott 1942 Cells of medium size, compressed in lateral view, with a deep median constriction. Semicells in front view suborbicu- late, generally subhexagonal to suboctagonal, with each lower lateral margin bearing a single, long, straight or slightly 342 recurved, simple or bifurcate horizontally projecting spine; each apical angle with a pair of granules or spines. Cell wall with irregularly arranged granules or verrucae, a single granule always in a median supra-isthmial position in each semicell, sometimes wall devoid of granules except for isthmial granule and a central facial proJection. Semicell in vertical view elliptic, with poles bearing long stout, simple or bifur- cate spines, sometimes accessory divergent spines placed on each side of the centrally placed polar spine. Zygospore unknown. 1. Spinocosmarium qgadridens (Wood) Prescott and Scott. Pl.ll, Fig. 3. Prescott and Scott, 1942. Trans. Amer. Microsc. Soc. 61(1):l6. Scott and Prescott, 1949. Trans. Amer. Microsc. Soc. 68(4): Pl. 1, Figs. 1—3. This compressed species has each lower lateral mar- gin of the semicell bearing a long, stout, straight or. slightly divergent simple or bifurcate spine. The apical angles may have short, single or paired spines. The cell wall has irregularly arranged granules and/or verrucae, a single granule always placed in a median supra-isthmial region in each semicell. 3 Measurements: L. 32-(34)-36u; W. ssp. 30-(30)~38u; W. csp. (42.6)-44-53u; I. 8-l3u. Distribution: NLP, Emmet. New record for>Michigan. T“ {w 343 19. XANTHIDIUM Ehrenb. 1837 Cells of variable size, frequently longer than broad in front view; usually compressed and narrowed in side view, and bilaterally symmetrical: semicells generally polygonal, sometimes transversely elliptic or hexagonal-elliptical; median constric- tion deep with the sinus linear to acute-angled; cell wall smooth or punctate, bearing simple, or rarely, furcate spines disposed asymmetrically in reference to a vertical plane and a thickened protuberant central facial area which is often scrobiculate; cells in vertical view usually elliptic, rarely triangular. Chloroplasts, four in each semicell when parietal, two in each semicell when axial; pyrenoids usually one in each chloroplast. Zygospore spherical, either spineless and scrobiculate or with simple or furcate Spines. Key to Species of Xanthidium 1. Cells somewhat elliptic in vertical view . . . . . . . . . . . . . . 2 1. Cells triangular in vertical view . (22) X. antilopaeum var. triquetrum 2. Margins of semicells with muc- ronate projections . . . . . (l) A, obsoletum 2. Margins of semicells with spines . . . . . . . . . . . 3 3. Spines in the form of broad furcate processes . . . . . . . . . . . . (2) A, armatum 3- Spines simple . . . . . . . . . . . 4 344 4. Lateral margins bearing a single pair of spines . . . . 5 4. Lateral margins bearing more than a single pair of spines. 7 Some portion of the face of semicell 6 wall thickened and scrobiculate Some portion of the face of semicell wall thickened but not scrobicu- late I O O 0 O O O O 0 O O O O O O (5) £0 Torreigi 6. Spines on lateral margins in- serted in different vertical planes . . . . . . . . . . . (6) X. tetracentrotum var.—intermed;§ 6. Spines on lateral margins in- serted in same vertical plane (7) A, subhastiferum var. Johhsonii Lateral margins with a pair of Spines on each apical and lateral angle, and with a single spins on the bas- al angle . . .... . . . . . . . . 8 Lateral margins otherwise . . . . . 9 8. Central area of semicell face with three-quarter circular row of scrobiculations . . . (17) X. antilopaeum fa. Michiganensis 8. Central area of semicell face smooth or with granules or scrobiculations, the scrobi- culations never arranged in a three-quarter circular row . (9) A, cristatum Lateral margins with three spines 10 Lateral margins with more than three Spines O o o o o o o o o e o o o o 11 10. Semicells elliptic-hexagonal . (19) A, antilopaeum var. oligacanthum 10. Semicells irregularly rectang- . ular, with angles exerted to form lobes . . . . . . . . . (5) A, Torrezi 11. 11. 13. 13. 345 Lateral margins with two pairs of spines . . . . . . . . . . . . . . l2 Lateral margins without two pairs of spines . . . . . . . . . . . . 14 12. Apex broadly truncate, spines inserted horizontally on api- cal angles . . . . . . . . . (15) A, Aylerianum 12. Apex not broadly truncate, spines inserted on apical angles divergent or almost erect . . . . . . . . . . . . l3 Supra-median region of the facial cell wall with an arcuate thick- ened band in which are two irreg- ular rows of scrobiculations . . . (8) A, subhastiferum var. Johnsonii Ta. Smithii Face of cell wall ornamented in var- ious ways but never as above . . . (16) A, antilopaeum 14. Lateral margins with three pairs of spines . . . . . . . . . . (23) A, fasciculatum l4. Lateral margins with more than three pairs of spines, may be somewhat scattered . . . . . (24) A, Brebisonii Xanthidium obsolgtum Taylor. Pl. 8, Fig. 3. Taylor, 1934. Pap. Mich. Acad. Sci. Arts and Letters. 19:275. P1. 17, Fig. 12. ' This species is characterized by the short incrass- ate projections at the upper and suprabasal angles. Specimens observed from Washtenaw County are questionably placed here because the projections from the angles were short, usually blunt, knob-like spines. They resemble the organism illustrated by Irenee-Marie(l938). Both his form and the specimens from Washtenaw County are possible undeveloped specimens of an unknown species of Xanthidium. 346 Measurements: L. 52-65-(84)u; W. 52-(61)-67u; I. (9.5)-l8-(2l)u. Distribution: SLP, Washtenaw. New record for Michigan. 2. Xanthidium armatum (Breb.) Rabenh. West and West, 1912. Monogr. Brit. Desm. 4:51. Pl. 104, Figs. 1-5. The possession of furcate spines separates this species from others reported from Michigan. The central protuberance is a large wart bearing simple or emarginate teeth. Measurements: L. csp. (107)-114; W. csp. (78)-l27u; I. (28)-46u. Distribution: NLP, Roscommon, also Cheboygan (N & A 1932, Welch, 1936b): EUP, Chippewa; WUP, Gogebic. 3. var. fissum. Nordst. west and West, 1912. Monogr. Brit. Desm. 4:54.” P1. 105, Figs. 1, 2. This variety differs from the typical by the more elongated spines and by the central protuberance being similar to the marginal spines. I Measurements: L. csp. l35-172u; W. csp. lO4—2l4u; I. 28-40u. Distribution: NLP, Cheboygan (Taft 1939); WUP, Gogebic. 4. var. irregularis West. West and West, 1912. Monogr. Brit. Desm. 4:55. Pl. 105, Figs. 3, 4. This variety is separated from the typical primarily on the basis of the variable disposition and character of 347 the spines. The spines are often reduced to emarginate or tridentate warts, but may be simple with obtuse ends. Measurements: L. cap. 172-181u: W. csp. 110-126u; I. 41-50u. Distribution: NLP, Cheboygan (Taft 1939). 5. Xanthidium.TorreyA_ Wolle Taylor, 1934. Mich. Acad. Sci., Arts and Letters, 19:277, P1. 56, Figs. 13-14. The Michigan specimens from Chippewa County are very similar to those illustrated by Taylor (op. cit) from.New Foundland. He believes that the irregular placement and deflection of spines necessitates the re- tention of this form in Xanthidium. There is some re- _ semblance to A, Agpgg (Jacobs) Gronblad and A, octocornis, :Ehrenb. but the closed linear sinus and the different form of semicells readily distinguishes it. Measurements: L. ssp. 32-34u: L. csp. 67-7lu; W. ssp. 28-35u; W. csp. 54-67u. Distribution: NLP, Cheboygan (Taft 1939): EUP, Chippewa. 6- Xanthidium tetracentrotum. Wolle £22: intermedia var. 321. P1. 8, Fig. 3. Semicells, elliptic hexagonal, with an elliptical section of central area of semicell wall thickened and scrobiculate, lateral margins bearing a pair of simple spines which curve upward. 'Vertical view rhomboid-el- liptical with poles bearing two simple curved spines which 348» are inserted in different planes, the arrangement of spines at one pole being alternate with those at the' other pole; cell wall punctate in a narrow median band extending from pole to pole. This organism seems to be intermediate between A, tetracentrotum fa. protuberans West and.West, and A, tet- racentrotum var. guadricornutum (Roy and Biss.) West and West. The Michigan specimens from Oakland County have the shape of the semicells and spines similar to the type exhibited by the former but have the irregularly disposed spines and the size of the latter. In vertical view, they are similar to the fa. protuberans, but lack the small lateral protuberances. The band of punctations in the dorsal cell wall is characteristic of only the Michi- gan specimens. This variety should be carefully compared with.A, subhastiferum var. Johnsonii fa. Smithii. Measurements: L. 53u; W. ssp. 46u; W. csp. 70u; I. 12.5u. Distribution: SLP, Oakland. 7. Xanthidium.subhastiferum var. Johsonii (West and West), G.M.&umn Smith, 1924. Wise. Geo. Nat. Hist. Surv. Bull. 57(2):61. P1. 67, Figs. 4-6. A, subhastiferum West, which has not been reported as yet from Michigan is a very distinctive species. The semicells are transversely elliptic or sub-elliptic with each truncate lateral margin bearing two divergent, straight or slightly curved spines that lie in the same vertical plane. 349 The variety Johnsonii was first described by West as a variety of A, hastiferum Turner, but has been trans- ferred to A, subhastiferum by Smith on the basis of sim- ilar shape and because the occurrence of accessory spines in this form is rare. The prrsence of the subapical row of pores and the two regularly placed spines on the lat- eral margin are the distinctive characteristics of this variety. Measurements: L. ssp. 48-(50)-57u: L. csp. 52-(52)-63u; W. ssp. 48-(48)-53u; W. csp. 75—(79)-95u; I. 12-5-(13)- 15u. Distribution: SLP, Oakland, also Washtenaw (West and West 1898) and Macomb (Johnson 1895); NLP, Presque Isle. 8. fa. Smithii fa. 22!, P1. 10, Fig. 2. Xanthidium subhastiferum var. Johnsonii(West&West)G.M.Smith fa. Smith, 1924. Wise. Geo. and Nat. Hist. Surv. Bull. 57(2):61, P1. 67, Fig. 7. Semicells subsemicircular with two pairs of spines borne on lateral margins, the lower pair slightly curved and inserted a slight distance apart and in a different ver- tical plane on the lateral margins, the upper pair inserted close together at the apical angles: the upper central re- gion of the face of the cell wall thickened and scrobicu- late, the scrobiculations.arranged regularly or irregularly in two arcuate rows. Vertical view elliptic with each pole bearing four spines arranged in different planes. This form differs from var. JohnsoniiCWest and West) G. M. Smith in possessing four spines irregularly dis- 350 posed upon the lateral margin whereas the variety has two spines that are arranged in the same plane on the lateral margin. The scrobiculations are arranged about halfaway between the apex and the face of the semicells, and thus lower than in variety. In addition, the scro- biculations are arranged in a double irregular row in a subarcuate band, in contrast to the single irregular row found just below the apex in the variety. The organism figured by Taylor (1934) as A, antilopaeum var. hebridarium West and West is closely related to this form because of shape of semicells and the number and arrangement of spines, although the arrangement of scrobiculations on the face of the semicell is different. The writer be; lieves Smith's (1924) A, subhastiferum var. Johnsonii fa. and the Michigan form from Mackinac County are distinc- tive enough (as discussed above) to qualify as a separate forma. Measurements: L. ssp. (64)u; L. csp. (70)u; W. ssp. (55)u; W. csp. (72)u; I. l2-(22)u. Distribution: EUP, Mackinac. 9. Xanthidium’ cristatum Breb. West and West, 1912. Monogr. Brit. Desm. 4:70. Pl. 110, Fig. 1. i This species is distinguished by the single conver- gent spine at the basal angles of the semicells and by the central protuberance which is usually not ornamented. 351 Measurements:‘ L. ssp. 44-55u; L. csp. 60-77; W. ssp. 34.5-48u; W. csp. 42-68u; I. 13-17u. Distribution: SLP, Barry; NLP, Cheboygan (N & A 1932); EUP, Alger, also Schoolcraft (N & A 1932); WUP, Gogebic, also Isle Royale (Prescott 1937). 10. var. leiodermum (Roy and Biss.) Turner West and West, 1912. Monogr. Brit. Desm. 4:72, P1. 110, Fig. 11. The lack of any ornamentation or modification in the central area of the semicell is characteristic of this variety, A, cristatum var. Hipparqui IreneeAMarie has the same characteristic but has truncate pyramidate shaped semicells, retusa lateral margins and a punctate cell wall which easily separates it from the var. 12327 dermum. Specimens from.Berrien County agree favorably with this variety except for a slight retuseness of the upper lateral margins. The insertion of the long spines on the lateral margins in the semicells of specimens is much closer than in the variety. This characteristic, the presence of long spines and the slight retuseness of the upper lateral margins approach A, cristatum var. longispina Gronblad (1921) which is a much larger variety. Measurements: L. ssp. (47).48-54u; L- 08P- 55-(56-5)- 74v: w. sap. (32)-366911: w. 0813- 53-55-(6OJu: I- (9.5)- 11-13u. Distribution: SLP, Berrien: NLP, Cheboygan (N & A, 1932). 352 11. var. Hippargui Irenee-Marie. Pl. 8, Fig. 4. Iréhee-Marie, 1938. Flor. Desm. de la Reg. Mont.:244. P1. 43, Fig. 6. _ This variety is characterized by the absence of any ornamentation or modification in the central area of the semicells. It is separated from A, cristatum var. leiodermum (Roy and Biss.) Turner by the truncate-pyra-' midate shape of the semicells, and by the punctation of the cell wall. Measurements: L. ssp. 46-(54)-60u; L. csp. 65-(67)-70u; W. ssp. 35-38-(39)u; W. csp. 50-(54)-56u; I. (lO.7)-l3-l4u. Distribution: SLP, Calhoun. New record for Michigan. 12. var. pgpilliferum IréheeéMarie P1. 9, Fig. 2. Irehee-Marie, 1938. Flor. Desm. de la Reg. Mont.:243. P1. 43, Fig. 13. The distinguishing characteristics of this variety are the single basal isthmial papilla and the mucronate projections.that close the sinus. Measurements: L. ssp. 57-59-(60u; L. csp. 71-(72)-75u; W. ssp. 45-47-(50u; W. csp. 45-47-(48)u; I. (13.3)-l4-15u. Distribution: SLP, Washtenaw, Jackson; WUP, Marquette. New records for Michigan. 13. var. uncinatum Breb. West and West, 1912. Monogr. Brit. Desm. 4:73. P1. 111, Figs. 2-4. This variety is distinguished from the typical by the more pyramidate semicells, the erect curved spines and by the central area of semicell wall in which gran- ules are irregularly disposed. Measurements: L. ssp. (53.7u): L. csp. 60-(64)-(74)-91u; w. ssp. (34)~36u; w. csp. (47)—51-(55)-83u; I. (10.5)- 12-20u. Distribution: SLP, Calhoun Barry (2), also Macomb (Taft 1939): NLP, Crawford, also Cheboygan, Presque Isle, Ostego (Taft 1939); EUP, Chippewa; WUP, Iron, Houghton, Gogebic(2); Isle Royale (Prescott 1937, 1940). 14. fa. mucronata West and West Pl. 9, Fig. 1. IreneeqMarie, 1938. Flor. Desm. de la Reg. Mont.:242. P1. 43, Figs. 10, 11. | This form is distinguished by the spines being in- flated at their bases, thus appearing to be inserted upon a protuberance of the cell wall. The semicell has a general trilobed appearance. Measurements: L. csp. 58-(74)-76u; W. ssp. (40)u; W. csp. 42-(54)-69u; I. 9-(10.5)-16u. Distribution: NLP, Emmet; WUP, Gogebic. New records for Michigan. 15. Xanthidium Tylerianum West West, W., 1889. Journ. Roy. Microsc. Soc. 5:19, Pl. 2, Figs. 1-4, Pl. 3, Fig. 14. ' The insertion of the spines in a horizontal plane at the apical angles and the broad truncate appearance of the semicell apex are characteristics which easily distinguish this specie. 354 Measurements: L. 66.3-70u; W. 62.4-80u; I. 20-25u. Distribution: WLP, Marquette (Pres. and Mag. 1935). 16. Xanthidium antilopaeum (Breb.) Kuetz. West and West, 1912. Monogr. Brit. Desm. 4:63. Pl. 118, Figs. 7-18. The hexagonal semicells with a pair of spines at both the apical angles and lateral angles distinguishes this species. A, Tylerianum has the same characteristics but differs in the spines at apical angles being hori- zontally placed whereas in A, antilppaeum, the spines at the apical angles are either divergent or almost erect. The spines may be variable in length and curvature as can the number and arrangement of the scrobiculations in the central area of the semicells. Measurements: L. ssp. 42-(44)-76; L. csp. 50-(54)-1l4u; W. ssp. 42-(44)-72u; W. csp. 57-(60)-108u; I. (13)-14-26u. Distribution: SLP, Barry, also Wayne (Campbell 1886) and Muskegon (Transeau 1917); NLP, Emmet, also Emmet (N & A 1932) Cheboygan, (Welch 1938b and Neal 1948); EUP, Chip- pewa (2), Schoolcraft, Delta; WUP, Marquette (2), Hough- ton; Isle Royale (Prescott 1937, 1940). 17. fa. michiganensis f3, 92!, P1. 11, Fig. l. Semicell hexagonal with a pair of long divergent ' spines at each apical and lateral angle, an single shorter convergent spine at each basal angle; central area of the cell wall with a three-quarter circular row of scrobicu- lations. 355 Specimens of this forma collected in Roscommon County appear to be intermediate between A, antilppaeum var. Crameri Gronbl. (Gronbl. 1921) and A. mauricianum (Ire/nee- Marie 1949b). The single spine at the basal angle is characteristic of A, cristatum Breb. The shape of the semicells and the single convergent spine at the basal angle are similar to A, mauricianum although the semicell outline is definitely hexagonal, IreneeéMarie's species being almost rectangular. The central facial area of the semicell wall has a three-quarter circular row of scrobi- culations that is also found in A, antilopaeum var. Crameri Gronblad. The paired spines on the lateral angles, how- ever, easily separate the Michigan form from this variety. The general semicell shape and the sharp convergence of the suprabasal margins towards the basal angles distin- guishes this form from A, cristatum. The hexagonal shape of the semicell and the similarity of the facial scrobiculations with var. Crameri makes retention of this form in A, antilopaeum.necessary despite the occur- rence of a single basal spine in both A, cristatum.and A, mauricianum. Measurements: L. ssp. (50)-u; L. csp. (70)u; W. ssp. (42)u; W. csp. (65)u; I. (10.5)u. Distribution: NLP, Roscommon. 18. var. basiornatum Eiclhl. and Racib. Pl. 9, Fig. 3. Eichler and Raciborski, 1893. Akad. Umiej. w, Krakow. Ser 2(6):125.' Pl. 3, Fig. 31. 356 Gronblad, 1921. Acta. Soc. pro. Fenn. et Flor. Fenn. 49(7):46 Pl. 4., Figs. l7-18. This variety is characterized by the angles being extended into short mammillate processes, each of which is terminated by a straight spine. A row of basal scro- biculations and a papilla in the central region of the semicell are also distinctive. Measurements: L. ssp. (50)-53u; L. csp. (85)u; W. ssp. (55)-60u; W- esp. (87)u: I. (25)-3lu. Distribution: EUP, Schoolcraft. New record for'North America. 19. var. oligacanthum Schmidle P1. 10, Fig. l. West and West, 1912. Monogr. Brit. Desm. 4:68. P1. 109, Fig. 5. This variety is distinguished from the typical and other varieties reported fromfiMichigan by the presence of a single spine at apical angles. West and West (1912) report that there is no central differentiated area, al- though Gronblad (1921) indicates that Finnish specimens always have a thickened (smooth or scrobiculate) central area. The few Michigan specimens observed were smooth. They were also longer than measurements given by West and West (1912). Measurements: L. ssp. 46-50-(59)u; L. csp. 70u; W. ssp. 46-(57)-58u; W. csp. 83u; I. (15.5)u. Distribution: NLP, Emmet. New record for.Michigan. 357 20. var. minneapoliense Wolle Wolle F., 1892. Desm, of the U.S., 2nd Ed.:10. P1. 63, Fig. 16. This variety has the same cell shape, subapical row of verrucae, and arrangement of spines as var. polygézum Nordst. but differs in the presence of a small erect spine either below or above the verrucae. Measurements: L. ssp. 50-(54)-72u; L. csp. (71)-75-138u; W. ssp. (50)-52-64u; W. csp. 72-(73)-l26u; I. (13)-15-20u. Distribution: SLP, Livingston; NLP, Crawford, also Che- boygan (N a A 1932); EUP, Schoolcraft; WUP, Marquette, Houghton, Gogebic. 21. var. polymgzum Nordst. West and West, 1912. Monogr. Brit. Desm. 4:67. P1. 108, Fig. 19. The subapical arc of verrucae easily distinguishes this variety. West and West (1912) state that there may be a third spine partially or fully developed in addition to the usual typical pair of spines at each lateral angle. No specimens observed by the writer demonstrated this characteristic. Measurements: L. ssp. (55)u; L. csp. 62-(73)-90u; W. sap. 53u; W. csp. 58-(75)-90u; I. 12-(12.5)-22u. Distribution: SLP, Barry (2), Berrien, Calhoun, Living- ston, Oakland, also Calhoun (Pres. and Mag. 1935); EUP, Delta; WUP, Menominee, Marquette, Gogebic, also Isle Royale (Taylor 1935, Prescott 1937, 1940). 358 22. var. triquetrum. Lund. P1. 11, Fig. 1. West and West, 1912. Monogr. Brit. Desm. 4:66. Pl. 109, Fig. l. The triangular shape in vertical view easily distin- guishes this variety. ‘West and West (1912) state that the central facial area of the cell wall between the arms is thickened, but does not mention, nor do their figures indicate whether this area is scrobiculated as in the typical plant. The Michigan specimens from Delta County have the central facial area thickened and scro- biculate. Okada (1934) illustrates the same characteristic. Measurements for the Michigan specimens are smaller than those given by West and West (1912). Measurements: L. ssp. (61)-81-90u; L. csp. (73)-ll6-l26u; w. ssp. (52)-65-82; w. csp. (71.5)-97-125; I. (15)-26.5-28u. Distribution: EUP, Delta. Except for a report of this variety by Wailes (1933) this is the only record for North America. 23. Xanthidium fasciculatum. Ehrenb. West and West, 1912. Monogr. Brit. Desm, 4:75. Pl. 111, Figs. 6-8. This species, sometimes confused with.A, antilopaeum (Breb.) Kuetz. is characterized by the presence of six pairs of equidistantly placed spines upon each.semicell. The shape of the semicell is angular-reniform and the central area is always slightly protuberant and usually granulate. 359 Measurements: L. ssp. 44-66u; L. cep. 65-74u; W. ssp. 44-59u; W. csp. 62-72u; I. 12-2lu. Distribution: SLP, Wayne (Campbell 1886). 24. Xanthidium.Brebissonii Ralfs. West and West, 1912. Monogr. Brit. Desm. 4:77. Pl. 112, Figs. 1, 2. This species is characterized by the presence of_ 8-10 spines upon each lateral margin of the semicell. These spines may be in pairs or irregularly disposed. Measurements: L. ssp. 61-80u; L. csp. 79-lOlu; W. ssp. 62-76u; W. csp. 80-104u; I. 18-27u. Distribution: NLP, Cheboygan (N a A 1932). 20. MICRASTERIAS Agardh. 1827 Cells usually solitary, very often of large size, nearly circular in outline but with the length generally slightly greater than width, bilaterally symmetrical (transverse and front view) and greatly compressed in lateral view, very deeply constricted with the isthmus never broad and the sinus usually linear or sublinear but open widely in some species. Semicells semicircular to hexagonal either with three primary lobes (polar and two lateral lobes) or with five primary lobes (polar, two lateral and two basal lobes); apolat-lobe gener- ally broadly cuneate and emarginate, sometimes with secondary (polar) lobules, often with accessory projections; primary lateral (and basal lobes if present) sometimes entire but 360 mostly subdivided into secondary lobes and lobules, the ultimate lobes or lobules generally with emarginate apices or spines. Cell wall rarely granulate, occasionally entirely covered with spines but usually smooth or with rows of spines within the wall margins adjacent to the incisions. Chloroplast on axial plate with the general contour of the semdcell; often with small ridges and containing numerous fairly well distributed pyrenoids. Zygospores spherical, covered with radially disposed spines that are simple to quadrified at their apices. Key to Species of Micrasterias l. Semicell with a single undivided lateral lobe present on each side 2 l. Semicell with more than one lateral lobe present on each side . . . . 6 2. Polar lobe bearing a single spine on each angle . . . . . 3 2. Polar lobe bearing more than a single spine on each angle . 3~ Lateral lobe bearing a single spine. 4 3. Lateral lobe hearing more than a single spine . . . . . . . . . . . (2) A, laticeps 4. Polar lobe convex . . . . . . . (6) A, oscitans var. mucFBEEEE——' 4. Polar lobe retuse . . . . . . . (1) A. arcuate var. expanse 5- Cell more than lOOu long . . . . . . (5) A, oscitans 5. Cell less than lOOu long . . . . . . (4) A, pinnatifida_ 361 6. Lateral margin divided only in- to a basal and a lateral lobe 7 6. Lateral margins otherwise . . . l3 7. Polar lobe without accessory projec- tions (in addition to polar lob- uleS) O 9 O . O O C O O O O C O O 8 7. Polar lobe with accessory project- ions (in addition.to polar lobulem ll 8. Cell wall just within margins ornamented with small spines. (10) A, mahabuleshwar- ensis var. ringens 8. Cell wall otherwise . . . . . . 9 9. Incision between polar and lateral lobes narrow and linear . . . . . (18) M. truncata var. quadrate 9. Incision between polar and lateral lobes wide and broadly open . . . A 10 10. Basal and lateral lobes very short and broad, about as long as wide . . . . . . . . (7) M. de en erata var. KitcHeIIEI 10. Basal and lateral lobes very long, about six times longer . than wide . . . . . . . . . . (23) A, radiate var. graEIIIIEE' 11. Polar lobe with.two to four upright projections between the polar lobules . . . . . . . . . . . . . (8) A, mahabulesh- warensis 11. Polar lobe with proj ctions in same planeaspolarlo‘s....... 12 12. Lateral margin of the polar lobe with accessory project- ions; both basal and lateral lobes entire . . . . . . . . (11) A, Nordstedtiana 13. 13. 15. 15. 17. 17. 19. 12. Lateral margin of the polar lobe without accessory pro- jections; both lateral and basal lobe bearing accessory projections in same plane . . Lateral margins divided into lateral and basal lobes, each of which are subdivided into secondary lobes that are either poorly developed or exserted into long processes, very rarely showing slight subdi- visions. . . . . . . . . . . . . . Lateral margins otherwise . . . 14. Polar lobe with accessory pro- jections (in addition to polar lobules) . . . . . . 14. Polar lobe without accessory projections . . . . . . . . . Incisions usually narrow and linear. Incisions widely open . . . . . . 16. Cell wall covered with flat- tened granules . . . . . . 16. Cell wall otherwise . . . . . Lateral and basal secondary lobes long and narrow . . . . . . . Lateral and basal secondary lobes short and broad . . . . . . . 18. Lateral incisions very deep, more than two-thirds the dis- tance to the mid-axis, the ultimate lobules slender . . 18. Lateral incisions less deep, less than two-thirds the dis- tance to the mid-axis, the ultimate lobules not slender. A single spine on each side of the apical emargination (not polar lobule spines) . . . . . . . . . . 362 (12) A, muricata 14 18 (13) A, americana 15 l6 l7 . (15) A, Jenneri . (16) A, truncata . (21) A, radiata (20) A, crux-melitensis 19 20 (24) A- 532.1. 19. 21. 21. 23. 23. 25. 25. 363 No spines on each side of apical emargination . . . . . . . . . . . (28) A, Torreyi 20. Cell under 170u long . . . . . 21 20. Cell over l70u long (sometimes (30) A, pgpilliflcea var. spec- 103a) I O O O O O O O C O O O 25 Polar lobules reflexed or reclinate, - each.with three to several apines. (32) A, conferta Polar lobules upright, each with two spines . . . . . . . . . . . . . . 22 22. Rows of spines within the mar- gins of the lobes which are separated by the deeper in- cisions . . . . . . . . . . . (29) A, papillifera 22. Rows of spines not present within the margins of lobes which are separated by the deeper incisions . . . . . . 23 Width of isthmus 15-23u . . . . . . (31) A. papillifera var. glabra Width of isthmus lO-l2u . . . . . . (34) A, novae-terrae 24. Polar lobules without spines . (35) A, denticulata 24. Polar lobules with spines . . . 25 Ends of lateral and basal lobules armed with strong spines . . . . . 26 Ends of lateral and basal lobules acute, or right-angled, sometimes with small projectmons but never with strong spines . . . . . . . . , 29 26. Almost entire surface of semi- cell wall covered with strong spines; middle area of sema- cell wall with.a small pro- jection ornamented with spines(37) A, apiculata 26. simicell wall with or without spines; spines if present more onhess restricted to the mar- gins of lobes; middle area of semdcell wall never with a pro- jection ornamented with spines 27 364 27. A single spine placed on each side of apical emargination (not polar lobules) . . . . . . . . . . . . . 28 27. A single spine not placed on each side of apical emargination . . . (42) A, rotata 28. Polar lobe broad, almost quad- rangular . . . . . . . . . . (40) M. apiculata var. BraEhyptera 28. Polar lobe not as broad, taper- ing distinctly towards base . (38) M. apiculata var.‘fimbriata 29. The upper margins of the apical in- . cisions sharply pointed . . . . . (41) A, Thomasiana var. notata 29. The upper margins of the apical em- argination not sharply pointed, but broadly rounded . . . . . . . (42) A, rotata 1. Micrasterias arcuate var. expanse (Bail.).Nordst. Krieger, 1939. Rabh. Krypt. Flor. l3(2):ll. P1. 9?, Fig. 4. This species has single, large, somewhat parallel lateral lobes which are tipped with a single spine and which are separated from the polar lobe by a large open sinus. The apices are retuse and the polar lobules are slightly divergent and tipped with a single spine. Measurements: L. 49-(75)-105u; W. 49-(79)-103u; I; 8- Distribution: NLP, Presque Isle; also Cheboygan (Taft 1938). 2. Micrasterias laticeps Nordst. Krieger, 1939. Rabh. Krypt. Flor. l3(2):l3. P1. 98, Fig. l. 365 This species differs from A. pinnatifida (Kuetz.) Ralfs in its much greater size and fromJA, oscitans Ralfs in the narrower lateral lobes and in the greater width of the polar lobe. Measurements: L. ll2-(ll6)-22lu; W. l22-(135)-265u; I. 15-(21)-37u: A. 110-250u. Distribution: SLP, Shiawassee, Barry (2), Washtenaw, also Wayne (Campbell 1886); NLP, Presque Isle; EUP, Alger, Schoolcraft; Isle Royale(Taylor 1935, Prescott 1937, 1940). 3. var. crassa Prescott Prescott and Magnotta, 1935. Pap. Mich..Acad. Arts, Sci., and Letters, 20:166. P1. 25, Fig. 7. This variety is separated from the typical by the greater thickness of the base of the lateral lobes. The polar lobe is broadly conical with the spines directed slightly downward. Measurements: L. lll-ll7u; W. 121-125u; I. 19u. Distribution: SLP, Calhoun, Washtenaw (both, Pres. and Mas. 1935)- ~ 4. Micrasterias pinnatifida (Kuetz.) Ralfs. Krieger, 1939. Rabh. Krypt. Flor. l3(2):l6. P1. 99, Figs. 6-9. The small size and the greater width of the incisions between the lobes readily distinguish this organism. Measurements: L. 40-(60)-80u; W. 37-(69)-84u; I. 9-(13}- 20u; A. 31-59u. 366 Distribution: SLP, Calhoun, Barry (2), Jackson, also Muskegon (Transeau 1917); NLP, Crawford, Emmet, also Cheboygan (N & A 1932); EUP, Alger; WUP, Houghton; Isle Royale (Prescott 1937, 1940). 5. Micrasterias oscitans Ralfs. Krieger, 1939. Rabh. Krypt. Flor. l3(2):23. Pl. 101, Figs. 8, 9. This species is much larger than A, pinnatifida (Kuetz.) Ralfs. and has wider lateral lobes and narrower polar lobes than A, laticeps Nordst. Measurements: L. l25-l63u; W. lOO-l48u; I. 23-30u; A. 77-95u. Distribution: SLP, Muskegon; NLP, Cheboygan (both Tran- seau, 1917). 6. var. mucronata (Dix) Wille Krieger, 1939. Rabh. Krypt. Flor. l3(2):24. Pl. 101, Figs. 10-12. This variety may have slight angular projections in the middle of the upper margin of the lateral lobes. The polar lobe is not as broad and the spines at the tip are directed more or less downward. Measurements: L. 125-160u; W. lO2-l40u; I. 23-33u; A. 74-87u. Distribution: NLP, Emmet (Transeau, 1917). 7. Micrasterias depauperata var. Kitchelii (Wolle) West a West Krieger, 1939. Rabh. Krypt. 13(2):39. Pl. 106, Figs. 3,4. 367 This variety is distinct but has a general resemb- lance to A, truncatg (Corda) Breb. from which it can be distinguished by the division of the lateral margin into a basal and a lateral lobe both of which are very short. A, truncate has the basal and lateral lobes divided into secondary lobes. Measurements: L. l25-(l29)-150u; W. (123)-l25-150u; I. 21-(2l.5)-27u; A. 75-lOOu. _ Distribution: SLP, Berrien; NLP, Cheboygan (N a A 1932). 8. Micrasterias mahabuleshwaregsi§_ Hobs. Krieger, Rabh. Krypt. Flor. l3(2):49. Pl. 107, Figs. 7-10. The possession of upright accessory apical processes distinguishes this form from other speciesexcept A. 9.41.93." AgAAA’(Ehrenb.) Ralfs. The latter has the basal and lateral lobes further subdivided into secondary lobes. Measurements: L. lOO—220u; W. 85-190u; I. 15-31u; A. 55-100u. Distribution: SLP, Calhoun, Washtenaw (Pres. & Mag. 1935); NLP, Presque Isle. 9. var. dichotoma G. M. Smith Krieger, 1939. Rabh. Krypt. Flor. 13(2):51. Pl. 110, Fig. A. This variety is distinguished from the typical by the development of a secondary process from the side of either or both the lateral and basal lobes. This process may be only slightly developed or may be entirely lacking in one of the semicells. 368 Measurements: L. 150-(150.5)-l65u; W. 115-(ll7)-l60u; I. 20-(2l.5)-3lu; A. 72u. Distribution: SLP, Barry, also Calhoun (Pres. & Mag. 1935). 10. var. ringens (Bailey) Krieger Krieger, 1939. Rabh. Krypt. Flor. l3(2):52. Pl. 110, Fig. 9. This variety is readily distinguished from the typi- cal by the lack of upright accessory processes. Measurements: L. 125-(137.6)-150u; W. 115-(118)-l30u; I. (15.5)u. Distribution: SLP, Barry, also Calhoun (Pres. & Mag. 1935) A, mahabuleshwarensis var. serrulata). 11. Micrasterias Nordstedtiana Wolle P1. 12, Fig. l. Krieger, 1939. Rabh. Krypt. Flor. l3(2):75. Pl. 120, Figs. 3-7. This species has several characteristics which readily distinguish it from A, muricata (Bailey) Ralfs. The polar lobe has accessory processes in the same plane, as does the latter species, but they are much shorter. In addition, A, Nordstedtiana has similar accessory pro- cesses developed from neck of lateral lobes. These may be greatly reduced. “The basal and lateral lobes are always entire. (Measurements: L. 134-(178.5)-203u; w. 115-(150.5)-180u; I. l4-(25.8)-28u; A. 138u. Distribution: SLP, Barry. New record for Michigan. 12. Agcrasterias muricata (Bailey) Ralfs. Krieger, 1939. Rabh. Krypt. Flor. l3(2):74. P1. 119, Figs.4-6. 369 The semicells of this species appear to have the lobes in three whorls. The polar lobes each bear two asymmetri— cally disposed secondary processes, the lateral lobes are subdivided into two secondary processes and the basal lobes possess two accessory projections in the same ver- tical plane as the lobes. Measurements: L. 150-200; W. 100-155u; I. 18-31u; A. 78-140u. Distribution: NLP, Presque Isle, also Cheboygan (Welch, 1938b). l3. Micrasterias americana (Ehrenb.) Ralfs. Krieger, 1939. Rabh. Krypt. Elor. l3(2):45. P1. 108, Figs. 5-8. This Species resembles A, mahabuleshwarensis in a general way but has the lateral and basal lobes further sub- divided into secondary lobes. Measurements: L. 104-160u; W. 86-145u; I. 17-19u; A. 50-81u. Distribution: SLP, Oakland, also Berrien (Transeau 1917); NLP, Cheboygan; EUP, Delta; WUP, Houghton (N & A 1932). 14. var. Boldtii' Gutw. Krieger, 1939. Rabh. Krypt. Flor. l3(2):47. P1. 109, Figs. 1-3. This variety has the polar lobe separated from the lateral margin by a shorter and narrower incision. The apex is plane or very slightly concave and the apical ac- cessory processes are greatly reduced. 370 Measurements: L. 110—143u; W. 93-128u; I. l9-28u; A. 53-83u. Distribution: Isle Royale (Prescott 1940). 15. Micrasterias Jenneri Ralfs. Krieger, 1939. Rabh. Krypt. Flor. 13(2):113. Pl. 135, Figs. 1, 2. The granulate cell wall of this species as well as the greater length to breadth ratio separates this species from A, truncata var. crenata (Breb.) Reinsch with which it might be possibly confused. Measurements: L. 127-188u; W. 80-130u; I. 22-34u; A. 60-8lu. Distribution: WUP, Marquette (Pres. & Mag. 1935). 16. Micrasterias truncata (Corda) Breb. Krieger, 1939. Rabh. Krypt. Flor. l3(2):25. APl. 102, Figs. 1-4. This very common species has the cells about as broad as long. The lateral and basal lobes (themselves separated by a short incision) are each divided by a short incision into secondary lobes each of which bears two short spines. The slightly convex apical lobe is very wide (about three-fourths the width of semicell) and is separated from the lateral ldbe by a short incision. Measurements: L. 75-(lOO)-l44u; W. 74-(93)—l35u; I- 10-(17.5)-30u: A. 55-97u: Distribution: SLP, Ingham, Jackson, Livingston, Oakland, 371 Barry (2), also Wayne (Campbell 1886) and Macomb (Pieters 1894); NLP, Roscommon, Crawford, Cheboygan, Presque Isle, Cheboygan (N & A 1932),(Welch 1936b, 1938b and Neel 1948) and Emmet (Transeau 1917): Eup, Chippewa (2), Schoolcraft (3), also Mackinac, Schoolcraft (Transeau 1917); WUP, Mar- quette, Houghton, Gogebic (2). 17. var. crenate (Breb.) Reinsch. Krieger, 1939. Rabh. Krypt. Flor. l3(2):29. Pl. 103, Fig. 3. This form is chiefly separated from the typical be- cause it lacks spines on the secondary lobes. Krieger (1939) states that this variety may be a reduction form of the typical.‘ Measurements: L. 75-(94.6)-l25u; W. (71)-74-102u; I. 15-(16)-30u; A. 46-65u. Distribution: SLP, Barry, also Calhoun (Pres. a Mag. 1935, A, crenate); NLP, Cheboygan (N & A 1932, A, crenate); WUP, Baraga. 18. var. Quadrata Bulnh. fa. P1. 13, Fig. 2. Krieger, 1939. Rabh. Krypt. Flor. l3(2):31. Pl. 104, Figs. 1, 2. This variety characteristically does not have the lateral lobes and basal lobes divided into secondary lobes as in the typical. The lateral and basal lobes each have a row of three to seven small granular projections at the end of the lobe. The specimens from Roscommon County 372 have the lateral lobe slightly divided by a very slight ' emargination into secondary lobes and five granular pro- jections at the tips. This latter combination is char- acteristic of A, truncata var. tridentate Benn., so that the Michigan specimens can be considered intermediate between the two varieties. Measurements: L. 85-(87)-l31u; W. (75)-76-l30u; I. 19-(22)-29u. Distribution: NLP, Roscommon. New record for Michigan. 19. var. semiradiata (Naeg.) Cleve. P1. 13, Fig. 1. Krieger, 1939. Rabh. Krypt. Flor. 13(2):32. P1. 103, Fig. 9. This variety is difficult to separate from the typi- cal. The cell shape is sometimes semicircular or the cell width is greater than the length. The apex is shallowly arched and the secondary lobes have longer spines than the typical. Measurements: L. 64-(85)-l28u; W. 60-(91.4)-124u; I. 13-(15)-l9u; A. 55-76u. Distribution: NLP, Presque Isle. New record for Michigan. 20. Micrasterias EggArmelitensis (Ehrenb.) Hass. Krieger, 1939. Rabh. Krypt. Flor. 13(2):62. Pl. 114, Figs. 5-8. The basal and lateral lobes of this species are each subdividediinto short, broad secondary lobes. The polar lobes are each exserted into two short, stout di- 373 vergent polar lobes giving the apex a broadly retuse margin. Measurements: L. 85-(120)-l64u; W. 78-(113)-153u; I. 11-(17.4)-28u; A. 35-60u. Distribution: SLP, Shiawassee, Washtenaw, Jackson also Macomb (Pieters 1894); NLP, Cheboygan (Transeau 1917, N & A 1932, Welch 1936a); EUP, Alger; WUP, Menominee; Isle Royale (Prescott 1937, 1940). 21. Micrasterias radiata Haas. Krieger, 1939. Rabh. Krypt. Flor. 13(2):68. Pl. 116, Figs. 4-6; P1. 117, Figs.l-4. Although there is considerable variation in the size of the polar lobules and the secondary lobes, the greater length and slimness of these lobes and the semi- cell shape readily separates this species from others. Measurements: L. 127-(159)-(198)-250u; W- 110-(138)- (189)-208u; I. 12-(17)-(22)-30u: A. 48-94u. Distribution: SLP, Wayne (Campbell 1886), Muskegon (Tran- seau 1917); NLP, Presque Isle; WUP,.Alger; Isle Royale (Prescott 1937, 1940). 22. var. pseudocrux Gronbl. fa. P1. 12, Fig. 2. Krieger, 1939. Rabh. Krypt. Flor. l3(2):72. P1. 118, Figs. 4, 5. This variety differs from the typical in the lat- eral incisions being less deep and in the secondary lobes being shorter. The polar lobe is wider at the base than 374 in typical. It approaches A. g_r_u_x_-melitensis but has longer polar lobules and basal and lateral lobes. The‘ Michigan Specimens are intermediate between the typical and this variety, the base of the polar lobe being more typical and the lateral lobes being shorter as in the variety. It is placed here because of the stouter ap- pearance of the entire cell. The measurements are slightly larger than the original. Measurements: L. 137-142-(157)u; W. 124-125-(139)u; I. 21; A. 57-61. Distribution: EUP, Schoolcraft. New record for North America. 23. var. gracillima Smith Krieger, 1939. Rabh. Krypt. Flor. l3(2):71. P1. 118, Fig. 1. This variety is distinguished from the typical by the lateral and basal lobes not being subdivided into secondary lobes. . Measurements: L. l35-190u; W. 130-170u; I. 15-18u; I. aboht 65u. Distribution: NLP, Presque Isle (Taft 1939). 24. Micrasterias §2A_ (Ehrenb.) Kuetz. Krieger, 1939. Rabh. Krypt. Flor. 13(2):93. Pl. 131, Fig. 1. Krieger (1939) has placed A. radiosa Ralfs. into synnonomy with A. sol. He considers these characteris- 375 tics as typical. The cell is medium-sized,about as long as wide, and divided into semicells by a linear incision that is slightly open at the end. The width of the lat— eral lobe is greater than the basal lobe, the former hav- ing the secondary lobes subdivided twice so that there are eight lobules on each lobe, the latter having the secondary lobes usually subdivided once so that there are four lobules on each lobe. All incisions are narrow and deep, the polar lobe is slim with parallel walls at the base and the apex has a spine on each side of a shallow emargination. The polar lobules are short with two spines each. Measurements: L. l40-220u; W. l25-215u; I. l6-26u; A. 25-38u. Distribution: SLP, Kalamazoo (N & A 1932) and Muskegon (Transeau 1917); NLP, Cheboygan (N a A 1932, Welch 1936b); Isle Royale (Prescott 1937, 1940). 25. var. ornata Nordst. Krieger, 1939. Rabh. Krypt. Flor. 13(2):96. Pl. 131, Figs. 3-5. This variety has rows of spines along the margins of the lobes which are separated by the deeper incisions (between the basal lobes of adjacent semicells, between lateral and basal lobes, and between the lateral and polar lobes). Measurements: L. ll6-228u; W. 110-245u; I. 15-26u; I. about 28u. Distribution: NLP, Cheboygan (Taft 1939). - -—— —_— 376 26. var. elegantior G. S. West. Krieger, 1939. Rabh. Krypt. Flor. 13(2):94. Pl. 132, Figs. 3, 4. Krieger (1939) raises this organism to varietal status although G. S. West originally considered it a form of var. ornata Nordst. The distinctive features are the very narrow and elongate polar lobe, the very deep and wider sinuses (except between semicells) than in the typical and the irregular undulate margins of the incisions. There are also rows of spines along the mar- gins of the major incisbns as in var. ornata. The writer believes that if this organism has varietal rank, then the organism illustrated by Prescott and Magnotta (1935) and identified as A, radiosa var. ornata Nordst. should have been placed under the var. elegantior by Krieger, rather than under var. ornata. Measurements: L. 150-(166)-248; W. 151-258u; I. l2-28u; A. 32-39u. Distribution: SLP, Barry, also Calhoun (Pres. & Mag. 1935). 27- var. Murrayi (West and West) Allorge Krieger, 1939. Rabh. Krypt. Flor. 13(2): Pl. 131, Fig. 6; Pl. 132, Fig. 1. This variety has the basal sinus widely open. The: incisions are all more Open than in the typical. The lobes are somewhat shorter and bear rows of spines along the major incisions as in var. ornata Nordst. 377 Measurements: L. 116-158u; W. 104-157u; I. l6-20u; A. 30-44u; Distribution: NLP, Cheboygan, (N a A 1932, A, Murrayi). 28. Micrasterias Torreyi (Bail.) Ralfs. Krieger, 1939. Rabh. Krypt. Flor. 13(2):97. Pl. 133, Figs. 2, 3. The large size and the palmate appearance of the semicell lobes are distinguishing features of the Species. Measurements: L. 250-410u; W. up to 450u; I. about 27u; A. about 74u. Distribution: SLP, Muskegon (Transeau 1917). 29. Micrasterias papillifera Breb. Krieger, 1939. Rabh. Krypt. Flor. 13(2):86. Pl. 129, Figs. 2-5. This species has a resemblance to A, AgA_var. ornata Nordst. and A, apgculata var. fimbrigta fa. spinosa (Biss.) West and West. It is easily distinguished from the for- mer by the more shallow incisions, the proportionately wider polar lobe, the somewhat octagonal shape, and the almost equal width of the lateral and basal lobes. It can be separated from A, gpiculata var. fimbriata fa. spinosa ‘9 the slightly less exserted and proportionately wider polar lobe and the almost equal width of lateral and basal lobes. Measurements: L. 95-(132)-170u; W. 95-(121)-l65u; I. 13-(19.3)-30u; A. 33-46u. 378 Distribution: SLP, Muskegon (Transeau 1917); EUP, School- craft, Delta; WUP, Gogebic; Isle Royale (Prescott 1937, 1940). 30. var. gpeciosa (Wolle) Krieger P1. 14, Fig. l. Krieger, 1939. Rabh. Krypt. Flor. 13(2):90. Pl. 130, Fig. 3. This variety is separated from the typical by the more open incisions, especially those between the polar lobes and the lateral lobes. The polar lobes are nar- rower and their margins are parallel at the base. Measurements: L. 104-(129)-l95u; W. 95-(116)-l72u; I. (13)-15-20u; A. 45-58u. Distribution: EUP, Chippewa. New record for Michigan. 31. var. glabra Nordst. Krieger, 1939. Rabh. Krypt. Flor. l3(2):89. Pl. 129, Figs. 6, 7. This variety lacks the rows of spines on the margins along the major incisions. Measurements: L. 84-160u; W. 84-135u; I. 15-23u; A. about 4lu. Distribution: SLP, Muskegon (Transeau 1917); NLP, Che- boygan (N a A 1932). 32. Micrasterias conferta Lund. Krieger, 1939. Rabh. Krypt. Flor. 13(2):91. P1. 126, Figs. 3-5. . This species can be distinguished by the reflexed nature of the two polar lobules, each of which bears 379 three to several spines. There is also a single spine on each side of the apical emargination. Measurements: L. (79)-80-100u; W. 70-(79)-90u; I. 14-(15)-18u; A. 36-44u. Distribution: NLP, Cheboygan (Welch 1938a); EUP, School- craft; Isle Royale (Prescott 1937). 33. var. hamata Wolle Krieger, 1939. Rabh. Krypt. Flor. 13(2):92. Pl. 126, Figs. 6-8. ‘ This variety has a wider incision between the polar lobe and the lateral lobes than the typical. This wider incision is a result of the different downward curvature of the lateral margin of polar lobe. Measurements: L. 75-128u; W. 73-107u; I. ll-l9u; A. 34-53u. ' ‘ Distribution: NLP, Cheboygan (Taft 1939). 34. Micrasterias novae-terrae (Cush.) Krieger Krieger, 1939. Rabh. Krypt. Flor. 13(2):91. Pl. 127, Figs. 6, 7. Krieger (1939) has elevated this organism to species rank from a variety of A. conferta Lund. It is near A. papillifera Breb. and the var. speciosa (Wolle) Krieger, .but lacks spines on the cell wall and has a wider lateral lobe and deeper incisions. Measurements: L. 102-150u; W. 93-ll6u; I. lO-l2u; A- 35-57u. Distribution: NLP, Cheboygan (Taft 1939). 380 35. Micrasterias denticulata Breb. Krieger, 1939. Rabh. Krypt. Flor. l3(2):108. Pl. 137, Figs. 3-6. This species can easily be separated from similar épecies (A, rotata (Grev.) Ralfs. and A, Thomasiana Archer) by the narrowly cuneate polar lobes with dilated apices and concave sides, and by the lack of spines upon the lateral and basal lobules. Measurements: L. 180-(268)-350u; w. l65-(2l8)-300u; I. 20-(25)-42u; A. 50-76u. Distribution: SLP, Washtenaw; NLP, Cheboygan (N & A 1932). 36. var. angulosa (Hantzsch) West and West Krieger, 1939. Rabh. Krypt. Flor. l3(2):107. P1. 138, Figs. 4-6. 4 This variety is separated from the typical by sev- eral features. They are the Slightly deeper incisions, the shorter polar lobe with the nearly straight sides and the almost rhomboid shape in vertical view. Measurements: L. 210-323u; W. l75-262u; I. 26-38; A. 42-70u. Distribution: SLP, Muskegon (Transeau 1917); NLP, Che- boygan (N a A 1932). 37. Micrasterias spiculata (Ehrenb.) Menegh. Krieger, 1939. Rabh. Krypt. Flor. l3(2):78. Pl. 122, Figs. 3, 4. Distinguishing characteristics of this species in- clude the numerous spines placed irregularly over the cell 381 wall and the median protrusion ornamented with a few spines in the central region at each semicell. Measurements: L. l70-300u; W. l40-250u; I. 29-40u; A. 53-90u. Distribution: SLP, Muskegon (Transeau 1917); NLP, Che- boygan (N & A 1932); Isle Royale (Prescott 1937, 1940). 38. var. fimbriata (Ralfs.) Nordst. Krieger, 1939. Rabh. Krypt. Flor. l3(2):81. P1. 123, Figs. 3-53 P1. 124, Fig. l. Krieger (1939) follows Ralfs in considering this organism to be of distinct specific rank. Many'modern workers however, consider it to be merely a variety of A, apiculata (Ehrenb.) Ralfs because of the same recurving of the spines on the lateral lobules and the same re- curving of apical spines (which are of different lengths). The variety differs in the polar lobe usually being less exserted, and less inflated, and the spines on the sur- face of the semicell wall usually being completely lack- ing. The writer believes that the similarity of cell (shape, the characteristic of types and curvatures of the spines and the report of many intermediate stages (West and West 1905) is sufficient evidence for retention of this organism as a variety of A. gpiculata. Measurements: L. l96-(2l8)-293u; W. 180-(192)-252u; I. 25-(26)-40u; A. 40-68u. Distribution: SLP, Calhoun, Crawford, Barry, also Wayne (Campbell 1886) and Macomb (Pieters 1894, A, fimbriata); Isle Royale (Prescott 1937). 39- #0. 382 fa. spinosa (Bissett) West and West Krieger, 1939. Rabh. Krypt. Flor. 93(2):83. P1. 124, Figs. 3, 4. I This forms of var. fimbriata is distinguished by the presence of rows of spines along the margins of the lobes which are separated by the apical-lateral incision and along the basal margins of the semicells. This or- ganism.was more common in the writer's collections than the typical, although it had only been reported once previously from Michigan. Measurements: L. l98-(229)-270; W. 169-(207)-267; I. (24)-25-39u; A. about 70u/ Distribution: SLP, Calhoun, Barry, Washtenaw (2), Liv- ingston; NLP, Presque Isle, also Cheboygan (Taft 1939); EUP, Schoolcraft; WUP, Menominee. var. bracthtera (Lund) West and.West Krieger, 1939. Rabh. Krypt. Flor. 13(2):84. P1. 125, Figs. 396; P1. 126, Fig. 1. This variety (considered a species by Krieger, 1939) differs from the typical in the shorter lateral and basal lobes, the fewer spines upon the semicell wall, and the relatively larger and wider polar lobe which is more ex- serted. Measurements: L. 182-(2lO)-234u; W. 131-(161)-180u: I. (21.5)~24-37u; A. 54-80u. Distribution: SLP, Calhoun (Pres. and Mag. 1935); EUP, Alger. 383 41. Micrasterias Thomasiana var. notata (Nordst.) Gronbl. Krieger, 1939. Rabh. Krypt. Flor. l3(2):lll. Pl. 140, Figs. 1-4. This organism can be easily distinguished by the three small sharply projecting facial swellings on each semicell Just above the isthmus. Measurements: L. 215-287u; w. l70-236u; I. 24-30u;‘ A. about 42u. . Distribution: Isle Royale (Prescott 1937, g, denticu- late var. notata). 42. Micrasterias rotata (Grev.) Ralfs. Krieger, 1939. Rabh. Krypt. Flor. 13(2):1oo. Pl. 136, Fig. 1. This species has the lateral lobes almost twice as wide as the basal lobes. The former are subdivided so that there are about eight to twelve lobules per lateral lobe. The basal lobes usually have four to eight lobules. The polar lobe is usually well exserted, and has two spines on each polar 106%. It is easily distinguished from m, apiculata var. fimbriata (Ralfs) Nordst. by the. absence of single spines on each side of the apical em- argination. This latter organism also has long spines at the tip of the lobules whereas 3, rotata has bidentate projections. Specimens from Barry and Livingston Counties have the secondary lateral lobes subdivided three times so that the lateral lobe has sixteen lobules. The basal lobes had eight lobules. A few specimens from Livingston 384 Counties approach the variety pseudo—guadridenta Gronbl., having the secondary lobes divided into only four lobules. A few of the lobules are tridentate as in the variety, but there is a slight emargination of others. These spec- imens have a similar appearance to g, papillifera var. glabra Nordst. (Krieger 1937, P1. 129, Fig. 6.), but are relatively larger and lack the pair of small teeth on each side of the apical emargination. The scarcity of specimens makes necessary the questionable assigning of these forms under g, rotata. Measurements: L. (191)—200-(226)-(294)-(301)-305u; w. (191)-165-(224)-(276)-(292>-3osu; I. (25)-26-(32)-43; A. 48-72. Distribution: SLP, Livingston, Barry, Shiawassee also Macomb (Pieters 189A); NLP, Crawford, also Cheboygan (Transeau 1917, N a A 1932, Welch 1936a, 1936b, 1938); EUP, Schoolcraft, Chippewa (N & A 1932), Mackinac (Tran- seau, 1917, N & A 1932) and Schoolcraft (Transeau 1931): WUP, Gogebic; Isle Royale (Prescott 19#O). 21. STAURASTRUM Meyen 1829 Cells variable in size, usually longer than wide (with- out processes or wall ornamentations), median constriction, often deep, with the sinus usually acute-angled at the apex. Semicells of variable shape, often triangular, hexagonal, cy- athiform, spherical, subcylindrical or transversely ellipsoidal in front view, the angles usually continued into processes of 385 variable length, the processes (arising in one or more trans- verse planes) often variably ornamented and terminated by spines or granules. Cell wall smooth, punctate or ornamented with granules, spines, mucros, denticulations or combinations of these structures. In vertical view, cells usually radially symmetrical (the triangular form most common), but sometimes showing bilateral symmetry. Chloroplast usually an axial mass (rarely parietal) with deeply incised lobes extending to each angle of the semicell, pyrenoid single in each axial mass or several in each lobe. ZngSpores usually spherical, more rarely angular, orna- mented with conical elevations that are continued into long Spines with simple or furcate apices. Species of this genus with simple form are often impos- sible to separate from radiate species of Cosmarium. The bi- radiate, simple-spined Species of Staurastrum are also diffi- cult to differentiate from Arthrodesmus. This overlapping of characteristics in these genera has been partly eliminated by the establishment of a new genus, Staurodesmus by Teiling (19h8) in which there is incorporated the biradiate, single- spined, smoothewalled species of Staurastrum.with similar species of Arthrodesmus. The writer, however, has chosen to retain the older system of classification until the exact limits of the genera and species concerned have been accepted by desmid authorities. Key to Species of Staurastrum l. Angles of cells not extended into hollow processes . . . . . . . . . l. Angles of cells extended into hollow processes . . . . . . . . . . . . 2. Cells with a very slight con- striction, semicells subcy- lindrical at base and angular at apex . . . . . . . . . . 2. Cells with a well marked con- striction, the semicells 3~6 angled or rarely compressed 3. Cell wall uniformly granulate . , . 3. Cell walls granulate only in upper part of semicells, with a row of verrucae at the base of the semi- cell . . . . . . . . . . . . . . . 4. Cell wall smooth or punctate, sometimes with mucros, but never with spines at angles 4. Cell walls either not smooth or punctate, or if smooth or punctate, then with spines at angles . . . . . . . . . . . 5. Each angle with a mucro or mammilla. 5. Each angle without a mucro . . . . 6. Lateral margins convex in ver- tical view . . . . . . . . . 6. Lateral margins slightly con- cave (in median part) in ver- tical view . . . . . . . . . 7- Sinus closed and linear . . . . . . 7 ‘ Sinus Open 0 e o o e e o o e o 8. Apices very slightly retuse 8. Apices not slightly retuse . . 66 (1) St, Meriani (2) St. capitulum var. spetSbergense 15 (3) _S__t_. tumidum (h) _33 brevispinum 8 10 (7) §, suborbiculare 9 11. 11. 13. 13. 15. 15. 17. 17. 19. Lateral margins broadly rounded in front view . . . . . . . . . . . . (8) S, orbiculare Lateral margins concave in median part in front view . . . . . . . . (14) S, trihedrale 10. Isthmus elongate . . . . . . . (15) S;_pseudopachy- rygchum lO. Isthmus not elongate . . . . . 11 Cell walls conspicuously thickened at angles . . . . . . . . . . . . (16) S, pachyrynchum Cell walls not conspicuously thick- . . . . . 12 ened at angles . . . . . 12. Angles mammillate . . . . . . . (17) S, subpygmaeum 12. Angles not mammillate . . . . . l3 Semicells obversely triangular . . . (18) S, clepsydra fa. Semicells transversely elliptic . . 14 14. Cell length more than 50u . . . (20) S, grande 14. Cell length less than SOu . . . (19) S, muticum Cell walls partially or wholly gran- ulate, angles without spines . . . 16 Cells smooth, punctate, granulate, spinate or verrucose; if granulate the angles bearing spines . . . .23 16. Granules restricted to angles . 17 18 16. Granules uniformly distributed. Apices with slight projections . . (23) S, Prescottii Apices without projections 18. Semicells angularly elliptic (sometimes rhomboid elliptic) 19 18. Semicells elliptic or oblong elliptic . . . . . . . . . . 20 Dorsal margin more convex than ven— tral margin . . . . . . . . . . . (24) S, dispar . . (22) S, trachzfithophorum 19. 21. 21. 23. 23. 25. 25. 388 Dorsal margin and ventral margins equally convex . . . . . . . . . . (25) S, punctulatum 20. Sinuses widely open, minutely acuminate or obtuse at apex . 21 20. Sinuses gradually and regularly opened . . . . . . . . . . . 22 Apices flattened or retuse . . . . . (27) S, striolatum Apices convex . . . . . . . . . . . (28) S, dilatatum 22. Granules irregularly arranged upon cell wall; angles broadly rounded; cells not twisted at isthmus . . . . . . . . . . . (31) S, turgescens 22. Granules regularly arranged upon cell wall, especially upon angles; angles less broadly rounded: cells usually twisted at isthmus . . . . . . . . . (30) S, alternans Cell wall smooth, punctate or granu- late, spines present only at angles 0 e e e e o e e e e o o 24 Cell wall covered with spines, or spines restricted to angular reg- ions; or cell wall with verrucae (that may be emarginate or re- duced) and with the angles trispin- ate or bispinate . . . . . . . . . 48 24. A single spine present at each angle a o e o e o o e o e o 25 24. More than one spine present at each angle . . . . . . . . 40 Cell wall granulate . . . . . . . 38 26 Cell wall smooth or punctate . . . . 26. Cells with a greatly elongated isthmus . . . . . . . . . . . (32) S, cuspidatum 26. Cells without a greatly elonga- ted isthmus . . . . . . . . . 27 27. 27. 29. 29. 31. 31. 33- 33. 35. 35. Semicells obversely triangular or obversely sub-semicircular, some- times almost transversely fusiform or semicircular . . . . . . . . . Semicells rhomboidal, transversely s 389 28 sub-elliptic, or elliptic . . (37) S, Dickiei 28. Semicells semicircular . . . (40) S. Dickiei var. Eirculare 28. Semicells obversely triangular or obversely sub-semicircular 29 Spines convergent . 30 Spines divergent or parallel . 31 30. Width of semicells without spines more than 30u . (42) S, megacanthum 30. Width of semicells without spines less than 30u . . . (41) S, glabrum Semicells obversely triangular (some- times almost fusiform) . . . . . 34 Semicells obversely semicircular . 32 32. Spines short, up to 6u long . 33 32. Spines well developed, 8—l3 long . . . . . . . . . . . . (42) S, connatum Spines divergent . . . . . . . . . (49) S, gglggggm, Spines dorsally inserted, more or less erect . . . . . . . . . . . (44) S, apiculatum 34. Ventral margins of semicells indented in front view ... (45) S, aristiferum 34. Margins not indented as above 35 Apex of semicells concave (cf. (52; S. ESEEEEEEEEE var. Sgoticum . (46) S, curvatum Apex of semicells straight or convex 36 . 113 u to 17u long (without 36 cespines) . . . . . . . . . . . (47) S, QfMearii 37. 37- 39- 39- 41. 41. 43. 43. 45. 45. 390 36. Cells more than 17u long (with- out spines) . . . . . . . . . 37 Cells about as long as wide (without spines); length without spines up to 28u . . . . . . . . . . . .(49) S, delectum Cells wider than long (without spines); length without spines rarely less than 30u . . . . . . . . . .(51) S, megacanthum 38. Semicells obversely triangular. 39 38. Semicells transversely ovate or hexagonal . . . . . . . . . . (91) S, cornutum Apex convex . . . . . . . . . . . . (53) S, granulosum Apex straight or very slightly con— vex . . . . . . . . . . . .(54) S. lunatum 40. Cell wall smooth or punctate . 41 40. Cell wall granulate . . . . . . 46 Cells hexagonal or pentagonal in ver- tical view . . . . . . . . .(55) S. Brasiliense var. Lundelli Cell triangular or quadrangular in vertical view . . . . . . . . . . 42 42. Cell quadrangular in vertical view . . . . . . . . . .(56) S. quadrangulare var. armatum 42. Cells triangular in vertical view . . . . . . . . . . . . #3 Three or four spines at each angle 44 Two spines at each angle . . . _ 45 44. Three spines at each angle . . (58) S. trifidum var. Iherxum 44. Four spines at each angle . . . (57) S, quadrispinatum Cells large, over 90u long . (59) S, longispinum Cells small, less than 30u long . . (61) S, aviculoides 47. 47. 49. 49. 391 46. Angles of the cells perceptibly continued into short cylin- drical processes .'. . . . . (65) S, subcruciatum 46. Angles of the cells not percep- tibly continued into short cylindrical processes . . . . 47 Semicells transversely oval, hexagonal; lateral margins in transverse view with at least two strongly devel- oped granules . . . . . . . . . . (91) S, cornutum Semicells transversely subelliptic or subtriangular; lateral margins in transverse view with several small granules, especially near the angles . . . . . . . . . . . . (cf. (66) S, subdenticulatum) (62) S, avicula 48. Cell wall ornamented with ver- rucae which may be either re- duced, emarginate and bi- or trispinate . . . . . . . 64 48. Cell wall ornamented with spines, which may entirely cover the cell wall or which may be restricted to the reg- ions of the angles . . . . . 494 Spines uniformly covering the cell walls . . . . . . . . . . . . 55 Spines not uniformly distributed over cell walls . . . . . . . 5o 50. Spines at the region of the angles of distinctly greater size than body spines, or spines present only near angles and often of two sizes 52 50. Spines at the region of the angles of the same size as body spines, or spines gradually be~ coming larger approaching the angles . . . . . . . . . 51 51. 51. 53. 53. 55. 55. 57. 57. 59. Semicell with two spines at each angle, and with three pairs upon apex; semicell wall otherwise with small sharp granules . . . . . . . (67) Semicell wall otherwise . . . . . . (84) 52. Cell length more than lOOu (with- out spines) . . . . . . . (68) 52. Cell length less than lOOu (with- out spines) . . . . . . . . Cell len th less than 30u (without spines 0 O O O O O O O C C O . Cell length more than 30u (without spines). . . . . . . . . . . . . 69) 54. Lateral angles truncate . . . . (73) 54. Lateral angles broadly rounded. (74) Semicell wall ornamented with short granular spines or emarginate ver- rucae with spines . . . . . . . Semicell wall ornamented with long distinct spines . . . . . . 56. 0611 length more than 26u . 56. Cell length less than 26u . . . (78) Cells 42-62.5u long . . . . . . . . (79) Cells less than 40u long 58. Semicell width 28-36u . . . . . (75) 58. Semicell width up to 28u . . (76) Spines few, about 10, restricted more or less to the region of the angles and apex . . . . . . . . . . . . . (77) Spines more numerous, not restricted to region of angles and apex . . 60 Cells over 84u long . . . . . . (83) var. 60. Cells shorter . . . . . 392 S, Simonyii gladiosum . minnesotense N” WJ .3... E |UJ |UJ S. 53 54 . setigerum . spiculiferum fa. . hystrix 56 59 57 . Bohlinianum . muricatum 58 . Ravenelli . echinatum . teliferum 60 Brebissonii maximum 61 393 61. Cells 77-79u long (without spines) . (80) S, saxonicum 61. Cells shorter . . . . . . . . . . . 62 62. Cells 48-67u long (without spines) . . . . . . . . . . . (81) S, polytrichum 62. Cells smaller . . . . . . . . . 63 63. Middle part of apex smooth (in trans- verse view) . . . . . . . . . . . (cf. (85) S, pilosum) (82) S, Brebissonii 63. Middle part of apex sparsely spines- cent . . . . . . . . . . . . . . . (84) S, gladiosum 64. Verrucae restricted to the apex and the angles . . . . . . . (86) S, maamense 64. Verrucae not restricted to the apex and angles . . . . . . . 65 65. A sin 1e large spine (sometimes bi- fid at each basal angle of the semicell; semicell wall otherwise ornamented with verrucae that are not spinate . . . . . . . . . . .‘(91) S, cornutum 65. A bi-trifid or emarginate verruca present at each basal angle of the semicell; cell wall orna- mented with same type of verrucae (88) S, spongiosum 66. Processes in one whorl . . . . 67 66. Processes not in one whorl . . 153 67. Processes smooth, extremities some- times emarginate, spinate or fur- cate . . . . . . . . . . . . 68 67. Processes undulate, crenulate or var- iously ornamented . . . . . . . . 71 68. Processes borne in pairs at angles . . . . . . . . . . . (94) S, laeve 68. Processes borne singly at angles 69 69. Cell length more than 20u . . . . . .70 69. Cell length less than 20u . . . . . (95) S, inconspicuum 71. 71. 73- 73- 75- 75. 77- 394 70. Ends of processes subdivided . (96) S, brachiatum 70. Ends of processes not subdivided(98) S, sublaevispinum Body of semicells (not including apex) ornamented with accessory spines or verrucae that are usually not uniformly distributed . . . . . . 72 Body of semicells (not including apex) not ornamented with accessory spines or verrucae . . . . . . . . 86 72. Semicells biradiate . . . . . . 73 72. Semicells not biradiate . . . . 74 Cells small, length with processes ' less than 20u . . . . . . . . . . (99) S, irregulare Cells larger, length with processes more than 20u . . . . . . . . . .(104) S, natator 74. Semicells hexagonal (in verti- cal view) . . . . . . . . . . (93) S, sexcostatum var. productum 74. Semicells not hexagonal (in ver- tical view) . . . . . . . . . 75 Body of semicells ornamented with verrucae . . . . . . . . . . 82 Body of semicells ornamented with one or more spines .~. . . . . 76 76. Lateral margins of semicell body between processes orna- mented with more than two spines . . . . . . . . . . 78 76. Lateral margins of semicell body between processes ornamented with two spines each of which may be reduced to a large gran- ule or bifurcately divided at the tip . . . . . . . . . . . ‘ 77 Base of semicell inflated and orna- mented with verrucae or granules .(140) S, quebecense var . govngtum 77- 79- 79- 81. 81. 83. 83. 85.) 395 Base of semicell not inflated and not ornamented with verrucae . . .(136) S, vestitum 78. Processes of semicells twisted.(114) S, controversum 78. Processes of semicells not twisted O I O O O O O I O O O 79 The base of each semicell ornamented with a transverse series of gran- ules or spines . . . . . . . . . . 81 The base of each semicell not orna- mented with a transverse series of spines or granules . . . . . . . . 80 80. Cell length less than 50u . . .(141) S, aculeatum 80. Cell length more than 50u . . .(132) S, Sebaldii A single row of spines present on each lateral margin between pro- cesses . . . . . . . . . . . . . .(134) S, Pseudosebaldii A double row of spines present on each lateral margin between pro- cesses . . . . . . . . . . . . . .(133) S, Sebaldii var. orna um 82. Semicells quadrangular in ver- tical view . . . . . . . . .(142) S, Cerastes 82. Semicells triangular in verti- cal view . . . . . . . . . . . 83 Semicells twisted at base so that processes on upper semicell are in different plane than processes in lower semicell when seen in trans- . verse view, or processes twisted . 84 Semicells or processes not twisted 8 as above 0 O O O O O O O O O O o O 5 84. Processes with long sharp spines at tip . . . . . . . .(114) S, controversum 84. Processes with small short spines at tip . . . . . . . .(130) S, proboscideum Verrucae restricted to lateral mar- gins Just below processes . . . .(133) S, Sebaldii var. ornatum 85. 87. 87. 89. 91. 91. 93- 93- 396 Verrucae forming a lateral marginal series between the processes . . .(146) S, anatinum 86. Semicells biradiate . . . . . . 87 86. Semicells not biradiate . . . . 99 Semicells twisted at isthmus . . . . 97 Semicells not twisted at isthmus . . 88 88. Apices smooth . . . . . . . . .(106) S, chaetoceras 88. Apices with ornamentation . . . 89 Apices with a single spine or verruca(lOO)S, leptocladum Apices with more than a single spine or verruca . . . . . . . . . . . . 9O 90. Spines on ends of processes of different length . . . . . .(103) S. grallatorium var . fore ipfgerum 90. Spines on ends of processes of about the same length . . . . 91 Semicells with lateral truncate pro- jections when seen in vertical view 92 Semicells without lateral truncate projections when seen in vertical View 0 o e o e o e e o e e e e o o 93 92. Central region of semicell wall ornamented with 6-8 granules or verrucae . . . . . . . .(104) S, natator 92. Central region of semicell wall smooth . . . . . . . . . . .(100) S, leptocladum Ornamentation present on cell wall below apical verrucae . . . . . . . 95 Ornamentation notpresent on cell wall below apical verrucae . . . . 94 94. Seven to ten apical verrucae present in face view . . . .(199) S, anchora 94. Less than seven apical verrucae present in face view . . . .(102) S, grallatorium 95. 95. 97. 97. 99- 99- 101. 101. 103. 397 Apical verrucae 4 . . . . . . . . .(105) S, brachioprominens Apical verrucae 5-8 . . . . . . . 96. Base of semicells with two trans- verse rows of granules or none, processes parallel or slightly 96 divergent . . . . . . . . . .(107) S, Johnsonii 96. Base of semicells with one trans- verse row of granules or none, processes usually slightly convergent . . . . . . . . .(110) S, bicorne Central region of semicell wall gran- ulate or verrucose . . . . . . . . (99) S, irregulare Central region of semicell wall not granulate or verrucose . . . . . 98 98. Cells 18-3lu long with processes(1l2)S, tetracerum 98. Cells 36-67u long with processes(lll)S, contortum Semicells with 5-9 processes, usually very long (in vertical view) . . . Semicells with 3-4 processes, if more than 4 processes.relativel short and stout(in vertical view . . 100. Apices with verrucae . . . . . 100. Apices without verrucae . . . . Processes poorly developed, the length of the processes not as great as width of cell body . . . Processes more developed, the length at least as great as width of cell bOdy O O O O O O O O O O O O O O O 102. Processes with two long spines at tips 0 O I O I O O C O 0 O 102. Processes without two long spines at tips . . . . . Processes of two semicells alternat- ing when seen in end view . . . . 137 100 120 101 102 110 103 104 (65) S, subcruciatum fa. 398 103. Processes not alternating when seen in end view . . . . . . . . . . . (65) S, subcruciatum 104. Processes strongly convergent .(113) S, crytocerum var . compac tum 104. Processes slightly convergent, horizontal or divergent . . . 105 105. Dorsal and ventral margins of semi- cells about equal in curvature, the semicells subfusiform . . . . . .(115) S, hexacerum 105. Dorsal margin of semicell not as con— vex as ventral margins, the semi- cells not subfusiform . . . . . . ' 106 106. Processes divergent, each pro- cess with two rings of denti- culations and four apical spines . . . . . . . . . . .(116) S, affine fa. 106. Processes not divergent . . . . 107 107. Processes with denticulate undulate margins . . . . . . . . . . . . .(125) S, crenulatum 107. Processes ornamented with minute granules . . . . . . . . . . 108 108. Cell length 34u or more . . . .(130) S; proboscideum 108. Cell length less than 34u . . . 109 109. Angles of semicells attenuated to form short blunt processes; base of semicells without a transverse row of granules . . . . . . . . .(123) S, polymorphum 109. Angles of semicells projecting into short obtuse processes; base of semicells sometimes with a trans- verse row of granules . . . . . .(127) S, margaritaceum 110. Cells small, length less than 20u without processes . . . . 111 110. Cells larger, length more than 20u without processes . . . . 116 111. Semicells with very long slender par- allel processes . . . . . . . . .(117) S, subgracillimum 111. 113. 113. 115. 115. 117. 117. 399 Semicells with shorter divergent processes . . . . . . . . . . . . 112 112. Length of cells without pro- cesses less than l2u . . . . 113 112. Length of cells without pro- . cesses l2u or more . . . . . 114 Semicells transversely subrectantu- lar, basal angles not rounded . .(118) S, iotanum Semicells cup-shaped or cuneate, basal angles rounded . . . . . . . QED S, paradoxum V8.1” . parvum 114. Length of cell with processes 77-84u . . . . . . . . . . .(122) S. paradoxum var. ‘Tongifies 114. Length of cell with processes below 77u . . . . . . . . . . 115 Basal angles broadly rounded . . . .(121) S, paradoxum var. parvum. Basal angles straight . . . . . . .(119) S, pseudotetracerum 116. Processes distinctly divergent.(l20) S, paradoxum 116. Processes horizontal or con- vergent . . . . . . . . . . 117 Processes with denticulate undulate margins . . . . . . . . . .(125) S, crenulatum Processes ornamented with minute granules . . . . . . . . . . . . 118 118. Processes twisted laterally in the same direction so that a processes from one semicell project between two processes of other semicells in front view. Semicells with a dis— tinct row of intramarginal granules (in transverse view)(l24) S, inflexum 118. Processes not twisted as above. Semicells sometimes with gran- ular ornamentation(in trans- verse view) . . . . . . . . 119 119. 119. 121. 121. 123. 123. 125. 125. 400 Angles of semicells projecting into short obtuse processes, base of semicell often with a transverse row of granules . . . . . . . . .(127) S, margaritaceum Angles of semicells attenuated into longer, stout processes. Base of semicell without a transverse row of granules . . . . . . . . . . .(123) S, polymorphum 120. Semicell base distinctly in- flated . O O O O O O O O O O O 121 120. Semicell base not inflated . . 124 Semicell base with at least one transverse row of granules or with two minute spines . . . . . . . 122 Semicell base without at least one transverse row of granules or with- out two minute spines . . . . . .(143) S, longiradiatum 122. Lateral margins with 2 small granules or spines between processes . . . . . . . . . .(140) S. quebecense var.‘3rn§tum 122. Lateral margins otherwise 123 Semicell base with 3 or 4 transverse rows of sharp granules . . . . . .(145) S, elongatum Semicell base with 2 minute spines at each lateral margin . . . . . .(144) S, pgotractum 124. Processes slightly developed, usually not as long as cell body is wide . . . . . . . . 125 124. Processes more developed, as long or longer than cell body is 130 wide 0 O O O O I O I O O O O Processes twisted (in transverse view)(ll3)S, cytocerum var.Compactum Processes not twisted (in transverse view) . . . . . . . . . . . . . 126 126. Processes with denticulate un- dulate margins . . . .(125) S, crenulatum 401 126. Processes ornamented with small granules . . . . . . . 127 127. Angles with well-developed spines at tips 0 O O O O O O o l O O O O 0 O 129 127. Angles with granular teeth at tips . 128 128. Verrucae in a linear series a- long lateral margin in trans- verse view . . . . . . . . . (131)S, proboscideum var. ornatum 128. Verrucae arranged ink circle or star-like arrangement, or placed singly on each side of the base of the processes . .(127) S, margaritaceum 129. Two spines at each angle . . . . . .(129) S, protectum var. planctonicum 129. Three spines at each angle . . . . .(135) S, rugosum 130. Each process with a bifurcate accessory projection above but near base . . . . . . . .(184) S, bicoronatum 130. Bifurcate projections not pre— sent as above . . . . . . . 131 131. Two verrucae present on each side of cell (in transverse view) . . . .(149) S, floriferum 131. More than two verrucae on each side of cell (in transverse view) . . 132 132. Only apical verrucae present . 134 132. Apical and subapical verrucae 133 present 0 O O O O O O O O O O 133. Subapical verrucae two, or if more than two, the middle two with well developed simple or bifurcate spines and much larger . . . . . . . . .(136) S, vestitum 133. Subapical verrucae more than two, or lateral margins between processes ornamented with spines . . . . . .(146) S, anatinum 134. Base of semicells with a trans- verse row of granules . . . .(150) S, boreale 135. 135. 137. 137. 139. 139. 141. 141. 402 134. Base of semicells without a transverse row of granules . 135 Isthmus of cell more than l5u wide, usually more than 20u . . . . . .(132) S, Sebaldii Isthmus of cell less than l5u wide . 136 136. A linear series of verrucae within each lateral margin when seen in transverse view, cells 42-52u long . . . . . .(151) S, Manfeldtii 136. A linear series of paired gran- ules within each lateral mar- gin when seen in transverse view, or if verrucae are pre- sent, the cells are less than 40u long . . . . . . . . . .(152) S, gracile Processes very long and slender . . 145 Processes short and stout . . . . . 138 138. Base of processes with small e- marginate projections on each side, or sharply serrate, or with a single spine on one side . . . . . . . . . . . . 139 138. Base of processes not as above. 141 Base of processes with small bifid . . . . . .(156) s. distentum projections . . . . . ‘_ var. Michiganensis Base of processes otherwise 140 140. Base of processes with a single spine on one side . . . . . .(155) §, gyrans 140. Base of processes not as above.(157) S, incisum Semicells without apical ornamentation other than granules . . . . . . . 141 142 Semicells with apical verrucae . . . 142. Cell wall ornamented with ver- rucae . . . . . . . . . . . . (93) S, sexcostatum var. predfictum 403 142. Cell wall not ornamented with verrucae . . . . . . . . . . 143 143. Apices with 2 or 3 emarginate ver- rucae just within the lateral mar- gin between processes (in trans- verse view) . . . . . . . . . . .(125) S, crenulatum 143. Apices with verrucae in circle or star-shaped position, or with a single verrucae on each side at the base of the processes . . . .(127) S, margaritaceum 144. Processes at angles of semi- cell attenuated . . . . . . .(123) S, polymorphum 144. Processes at angles of semi- cell obtuse and short . . . .(127) S, margaritaceum 145. The base of processes with a single Spine on one side . . . . . . . .(155) S, EZZanS 145. The base of processes otherwise . . 146 146. Base of processes separated by a narrow linear incision (in vertical view) . . . . . . .(157) S, incisum 146. Base of processes not separated by a narrow linear incision (in vertical view) . . . . . 117 147. Semicells with five processes (in vertical view) . . . . . . . . . . 148 14?. Semicells with more than five pro- cesses (in vertical view) . . . . 150 148. Width of cell with processes ”0-6511 0 e e o e e o o o o e (161) _Sl_o AraChne 148. Width of cell with processes 149 more than 65u . . . . . . . 149. Inner or ventral margin of processes crenulate . . . . . . - . - . . .(160) S, an oides var. pentacEaamm 149. Inner margin of processes smooth . .(158) S, pentacerum 150. Semicells with 6 or 7 processes (in vertical view) . . . . . 151 150. Semicells with 8 or 9 processes (in vertical view) . . . . . l52 404 151. Base of semicells with a transverse row of conical verrucae . . . . .(162) S, Ophidfi 151. Base of semicells without a trans- verse row of conical verrucae . .(158) S, pentacerum 152. Base of processes with verrucae(l62) S, Ophiura 152. Base of processes without ver- rucae, processes with trans- verse rings of granules . . .(159) 153. Vertical view (of semicell body) tri- angular or quadrangular . . . . . 155 153. Vertical view (of semicell body) cir- Onlar o e o e e e e e e e e e e e 154 154. Upper accessory whorl of four processes present . . . . . .(166) S, leptacanthum 154. Upper accessory whorl of six processes present . . . . . .(164) S, Arctiscon 155. All provesses smooth, not granulate nor undulate . . . . . . . . . . 156 155. Processes not all smooth . . . . 159 156. Each semicell with 15 processes, (also possibly S. Hantzschii, which has becomE confused In the literature . . . . . . .(167) S, senarium 156. Each semicell with 9-12 processes 157 . . (168)S, gemelliparum 158 157- Each semicell with 12 processes 157. Each semicell with 9 processes . . . 158. Cells less than 26u long without processes . . . . . . . . . .(169) S, furcatum 158. Cells more than 26u long without processes . . . . . . . . . .(177) S, tohopekaligense 159. Processes in lower whorl granulate, processes in upper whorl smooth . 160 159- Processes in both whorls granulate .(179) S, furcigerum 405 160. In transverse view, each later- al margin possessing two pro- cesses upon the margin and two processes within the mar- gin . . . . . . . . . . . .(175) S, forficulatum 160. In transverse view, each later- al margin possessing two pro- cesses within the margin . . 161 161. Angles sharp in transverse view . . 163 161. Angles rounded or truncate in trans- 162 verse view . . . . . . . . . . . 162. Body of semicell granulate . .(173) S, arcuatum 162. Body of semicell not granulate, granules restricted to ends of lower whorl processes . .(172) S, furcatum var. pisciforme 153- Lateral margins straight or convex in transverse view . . . . . . . .(182) S, monticulosum 163. Lateral margins slightly concave . .(174) S, arcuatum var. pseudopisciforme fa. Irenee-Marie 1. Staurastrum Meriani Reinsch West and West, 1912. Monogr. Brit. Desm. 4:122. P1. 118, Figs. 11-60 This species has the bases of the semicells sub- cylindrical, the apices of the semicells angular and the wall uniformly granulate. Measurements: L. 36-46u; W. at base, 17-20u; W. at apex, 20-26u; I. 13-18u. Distribution: SLP, Berrien (Transeau 1917), Lapeer (N a A 1932). 2. Staurastrum cap1tulum var. spetsbergense (Nordst.) Cooke West and West, 1912. Monogr. Brit. Desm. 4:126. P1. 118, Fig. 8. 406 This species has subcylindrical semicell bases, and angular apices. The apices are granulate and the basal portion of the semicell has a transverse row of verrucae. Measurements: L. 34-50.7u; W. at base 26-28u; W. at apex 31-33u; I. 12-20u. Distribution: Isle Royale (Prescott 1937, 1940). 3. Staurastrum tumidum. Breb. West and West, 1912. Monogr. Brit. Desm. 4:142. P1. 122, Figs. 1-5. This species (triangular or quadrangular in trans- verse view) has a mammilla at each angle of the semi- cell, and the lateral margins are convex in vertical view. Measurements: L. 97.5-134u: W. 78-127u; I. 44-50u. Distribution: WUP, Marquette (Pres. & Mag. 1935). 4. Staurastrum breviSpinum Breb. P1. 22, Fig. l. West and West, 1912. Monogr. Brit. Desm. 4:145. Pl. 123, Figs. 1-3. This Species has transversely oblong elliptic semi- cells with a small mucro at each angle. The concave lateral margins in vertical view distinguishes it easily from S, tumidum. Measurements: L. 27-(32)-50u; W. 27-(32)-49u; I. 8-17u. Distribution: SLP, Oakland. New record for Michigan. 5. var. retusum.(West and West) Borge P1. 22, Fig. 3. West and'West, 1912. Monogr. Brit. Desm. 4:148.Pl. 123, Fig. 6. 407 This variety is separated from the typical by the slightly retuse apices. Measurements: L. 35-52-(53)u; W. 36-40-(41)u; I. 11- (13)-l4u. Distribution: SLP, Barry. New record for Michigan. 6. var. Boldtii Lagerheim P1. 22, Fig. 2. Smith, 1924. Trans. Wisc. Geo. & Nat. Hist. Surv. 57(2):68. P1. 67, Figs. 16-17. This variety is proportionately longer than the typical. Measurements: L. 40-(47)-47u; W. (34)-38u; I. 9-11-13.5u. Distribution: NLP, Cheboygan. New record for Michigan. 7. Staurastrum suborbiculare West and West West and West, 1912. Monogr. Brit. Desm. 4:159. Pl. 125, Figs. 3-5. This species has pyramidate-sub-semicircular semi- cells with narrow and slightly retuse apices. Measurements: L. 35-(38)-44u; W. (33)-34.2-38u; I. 7.5-9.5-(10.5)u. Distribution: SLP, Livingston, also Calhoun (Pres. & Mag. 1935); EUP, Schoolcraft; WUP, Gogebic. 8. Staurastrum orbiculare Ralfs. P1. 22, Fig. 4. West and West, 1912. Monogr. Brit. Desm. 4:155. P1. 124, Figs. 10, 11. This species has sub-semicircular semicells with apices slightly depressed and the lateral margins broadly 408 rounded. The vertical view is triangular with slightly concave sides and broadly rounded angles. Measurements: L. 25.5-(43)-56u; W. 23-(43)-49u; I. 8-l6u. Distribution: SLP, Oakland; WUP, Gogebic. New records for Michigan. 9. var. Ralfsii West and West P1. 22, Fig. 6. West and West, 1912. Monogr. Brit. Desm. 4:156. P1. 124, Figs. 12, 13, 15, 16. This variety is separated from the typical by the subtriangular shape of the semicells. Measurements: L. 31-(32)-41u; W. 22-(29)-36u; I. 7-(8.5)-11u. Distribution: SLP, Barry; EUP, Mackinac. New records for Michigan. 10. var. truncatum Prescott Prescott, 1940. Mich. Acad. Arts. Sci. & Letters. 25:93. P1. 3, Figs. 14 and 20. This variety is often larger than the typical. The upper lateral margins are more nearly straight than in the typical and the apex is broadly truncate. L. (60)-(69)-70-74.5u; W. 60-63-(64)u; Measurements: I. (15)-19-5u. 'Distribution: EUP, Delta; Isle Royale (Prescott 1940). 11. var. ggtensum. Nordst. P1. 22, Fig. 5. West and West, 1912. Monogr. Brit. Desm. 4:158. P1. 125, Figs. 1, 2. 409 This variety has cells that have a greater length to width ratio than the typical. The smaller size sep- arates it from.SS, cosmarioides Nordst. which has not been found in Michigan. Measurements: L. 38-(40)-48u; W. 25.5-(28)-36u; I. 8-(10.5)-14u. Distribution: SLP, Oakland; WUP, Gogebic (2). New records for Michigan. 12. var. hibernicum West and West West and West, 1912. Monogr. Brit. Desm. 4:156. Pl. 125, Figs. 5—9. This variety has more pronounced basal angles than the typical’and flattened apices. Measurements: L. 42-(47)-65u; w. 36-(43)-57u; I. 9.5-(15)-20u. Distribution: SLP, Washtenaw; NLP, Cheboygan (N & A 1932); EUP, Schoolcraft; WUP, Marquette; Isle Royale (Prescott 1941). 13. var. ggpressum Roy and Biss. West and West, 1912. Monogr. Brit. Desm. 4:158. Pl. 124, This variety has much smaller cells than the typi- cal. The semicells are depressed and the cell wall is smooth. There is some resemblance to S, muticum.Breb. from'which it can be separated by the closed sinus. Measurements: (22)-22-(24)-27u; W. 20-(22)-27u; I- 6-(7)-7 5-(8.5)u- 410 Distribution: SLP, Oakland, Barry; NLP, Cheboygan (N & A 1932); EUP, Schoolcraft, also Schoolcraft (N & A 1932); WUP, Menominee, Marquette; Isle Royale (Prescott 1940). 14. Staurastrum trihedrale Wolle Wolle, 1892. Desm. of the U. 3.:136. P1. 51, Figs. 12, 14. This species has triangular semicells which have lateral margins distinctly concave medianly. Measurements: L. (43)u; W. (27.5)u; I. 10.5u. Distribution: NLP, Cheboygan (N a A 1932); WUP, Goge- bic (2). 15. Staurastrum pseudopachyrynchum Wolle P1. 22, Fig. 9. Smith, 1924. Wisc. Geo. & Nat. Hist. Surv. 57(2):69. P1. 68, Figs. 1-3. This smooth-walled species has rhomboidal-elliptic semicells with the apices convex and more tumid in the median region. The isthmus is narrow and elongate. The vertical view is triangular with the lateral margins concave and the angles broadly rounded. Measurements: L. 22-34-(40)u; W. 20-(23)-35u; I. (6.5)- 10.5u. Distribution: EUP, Alger. New record for Michigan. 16. Staurastrum pachygygchum Nordst. West and West, 1912. Monogr. Brit. Desm. 4:151. Pl. 121, Figs. 8, 9. This species has subelliptic or elliptic-subtriang- ular semicells with the angles conspicuously thickened. 411 The vertical view is 3-5 angled with the lateral margin concave and the angles obtusely rounded. Measurements: L. (21.5)-24-(40)-45u; W. 22-(23.5)-(37)- 45u; I. 7.8-(8.5)-15u. Distribution: SLP, Calhoun, Oakland; NLP, Presque Isle, also Cheboygan (N a A 1932, Welch 1936a); Isle Royale (Prescott 1937, 1940). 17. Staurastrum subpygmaeum West P1. 22, Fig. 7. West and West, 1912. Monogr. Brit. Desm. 4:162. P1. 125, Figs. 13-16. The semicells of this species are widely cuneate with the apices and lateral margins convex. The lateral angles are mammillate. The lateral margins are convex and the angles mammillate in the triangular end view. Measurements: L. 42-(52)-53u3 W- 39.5-(43)-52u; I. 16-22.5-(23)u. Distribution: NLP, Emmet. New record for Michigan. 18. Staurastrum Clepsydra Nordst. fa. P1. 22, Fig. 8. West and West, 1912. Monogr. Brit. Desm. 4:152. P1. 122, Fig. 6. ' The apices of the obversely subtriangular semicells are straight or convex and the angles are very slightly exserted and sometimes submucronate. The semicells are triangular in vertical view, with the lateral margins somewhat concave and the angles slightly rounded and sometimes slightly mucronate. The specimens from Oakland 412 County are smaller than the typical. Measurements: L. (18)-27-31u: W. (25)-27-36u; I. 6-8u. Distribution: SLP, Oakland. New record for Michigan. 19. Staurastrum muticum Breb. West and West, 1912. Monogr. Brit. Desm. 4:133. P1. 118, Figs. 16-20. This species has elliptic, elliptic-sub-semicircu1ar or subreniform semicells and an open sinus. The vertical view is triangular or quadrangular with concave lateral margins and broadly rounded angles. Measurements: L. (22)-22-(26)-43.5u; W. (22)-22-(24)-4lu; I. 7.5-(8.5)-12u. Distribution: SLP, Calhoun, Barry (2), also Ingham (N a A 1932) and Macomb (Pieters 1894); NLP, Emmet, Craw- ford, also Cheboygan (N a A 1932). 20. Staurastrum grande Bulnh. West and West, 1912. Monogr. Brit. Desm. 4:140. Pl. 119, Figs. 11-13; P1. 120, Fig. 1. This very large species has elliptic to subelliptic semicells that have the lateral angles acutely rounded. The ventral margins may be more convex than the dorsal margins, or about equal. The vertical view is triangular or quadrangular with the lateral margins slightly con- cave and with the angles acutely rounded. Measurements: L. 84-100u; W. 80-lllu; I. 21-25u. Distribution: Cheboygan (N a A 1932). 413 21. var. parvum. West P1. 23, Fig. 1. West and West, 1912. Monogr. Brit. Desm. 4:141. Pl. 120, Figs. 2, 3. This variety is separated from the typical by the smaller size and the more broadly rounded angles. The Michigan specimens from Calhoun County are smaller than the typical. ‘Measurements:L.(56)-60-65u; W. 47-56-61u; I. (9)-13.5-17u. Distribution: SLP, Calhoun. New record for Michigan. 22. Staurastrum trachytithophorum West and West West and West, 1912. Monogr. Brit. Desm. 4:165. P1. 126, Figs. 1, 2. The widely cuneate semicells of this Species have the angles slightly upturned and mammillate; each angle . with two rings of granules. The vertical view is tri- angular with the lateral margins slightly convex and the angles slightly produced, mammillate and ornamented with two rings of granules. The Michigan specimens from School- craft County have the angles less mammillate and the apices additionally ornamented with three pairs of gran- ules, one pair just back of each second transverse ring of granules. The size is also much smaller. Measurements: L. (25.5)-30-34u; W. (23)29-32.5u; I. (10.5)-10.5-ll.5u. Distribution: EUP, Schoolcraft, also Chippewa (N & A 1932). 414 23. Staurastrum Prescottii sp. nov. This small organism, collected in abundance in Ros- common County appears to be a new species. The cell is longer than broad, with elliptic semicells that are trun- cate at the apices. The sinus between the semicells is acute angled at the apex and gradually Opening to the outside. The lateral margins are truncate with broadly rounded angles and ornamented with 3-4 concentric series of granules. The apices bear a row of very Short bifid ridges. In vertical view the semicells are triangular with straight or very slightly concave lateral margins. The angles are truncate with broadly rounded apices and with 3-4 concentric series of granules. Across each angle and just within the concentric series of granules, there is a pair of lunate ridges, each ridge accompanied inwardly by a Shallow depression which is conspicuously punctate. Measurements: L. 20-2lu; W. 16-l7u; I. 6.5-7u. Distribution: NLP, Roscommon. 24. Staurastrum dispar Bréb. West and West, 1912. Monogr. Brit. Desm. 4:187. P1. 127, Fig. I. This species has narrowly elliptic-rhomboid or el- liptic-fusiform semicells which are uniformly granulate. The vertical view is triangular with the angles acute and alternate with angles of other semicell. The lateral 415 margins are convex. The writer has been able to examine only an illustration of a form shown by West and West (1912). Measurements: L. 27.5u; W. 27-28u. Distribution: NLP, Cheboygan (N & A 1932). 25. Staurastrum punctulatum Breb. West and West, 1912. Monogr. Brit. Desm. 4:179. P1. 127, Figs. 8-11, 13, 14. The sub-rhomboid-elliptic semicells of this species are uniformly granulate and the angles are acutely rounded. The vertical view is triangular (rarely four or five ang— ular) with the angles of one semicell partly or completely alternating with angles of other semicell. The lateral margins are slightly retuse and the angles are uniformly covered with concentric series of flattened depressed granules. The granules are irregularly scattered at the apex. Measurements: L. 26-40.5u; W. 23-36.5u; I. 8-l6u. Distribution: SLP, Wayne (Campbell 1886), Berrien (Tran- seau 1917), Washtenaw (N a A 1932); NLP, Cheboygan, Emmet, Mecosta (N a A 1932); Isle Royale (Prescott 1940). 26. var. pygmaeum. (Breb). West and West P1. 23, Fig. 2. West and West, 1912. Monogr. Brit. Desm. 4:184. P1. 128, Figs. 1, 2. This variety is distinguished from the typical by the more acute granules and the wider isthmus. This var- 416 iety sometimes also possess straight lateral margins in transverse view which are never found in the typical. Measurements: L. 27-42-(43)u; W. 24-(39)-40u; I. 13.5-(15)-18u. Distribution: SLP, Calhoun, New record for Michigan. 27. Staurastrum striolatum (Naeg.) Archer West and West, 1912. Monogr. Brit. Desm. 4:177. Pl. 127, Figs. 1-5. This species has oblong elliptic semicells with straight or slightly retuse dorsal margins. The angles are furnished with concentric series of granules, and the areas between the angles are also granulate. The vertical view is 3-4 angular, the granulate rounded or subtruncate angles sometimes alternating with angles of the other semdcell. The lateral margins are concave. Measurements: L. (l9)-l9-(22)-(24)-28u; W. 18-(22)-28- (30)u: I. 6-(8.6)-10u. Distribution: SLP, Calhoun, Washtenaw; NLP, Cheboygan (N a A 1932): EUP, Schoolcraft. 28. Staurastrum dilatatum Ehrenb. West and West, 1912. Monogr. Brit. Desm. 4:172. P1. 126. Figs. 10-15. This species has transversely elliptic-subfusiform semicells with a convex dorsal margin. The cell wall granulation is in concentric rows around the angles and in regular series between the angles. The vertical view 417 is 3-5 angled with the angles sometimes alternating with the angles of the other semicells. Measurements: L. 21-(36)-46u; W. 22-32-46u; I. 7.5-(8.5)—l3u. Distribution: SLP, Barry, ivingston, Washtenaw, Oakland; NLP, Crawford, Emmet, also Cheboygan (N & A 1932); EUP, Alger, Schoolcraft (2); WUP, Marquette, Gogebic, Houghton. 29. var. hibernicum West and West West and West, 1912. Monogr. Brit. Desm. 4:175. P1. 126, Fig. 18. This variety has the basal portion of the semicell more pronounced than the typical. The granules are ir- regularly scattered on the body of the cell, but arranged in concentric rings on the angles. Measurements: L. 22.5-24u; W. 21-24u; I. 7-7.5u. Distribution: Isle Royale (Prescott 1940). 30. Staurastrum alternans Breb. West and West, 1912. Monogr. Brit. Desm. 4:170. Pl. 126, Figs. 8, 9. This species has narrowly transverse oblong-elliptic semicells with rounded angles. The Sinus is widely open and acute at the apex. The cells are triangular in ver- tical view, the angles of one semicell alternating with the angles of the other semicell. The lateral margins are concave, and the cell wall is granulate with the gran- ules in concentric rows around angles, but irregularly 418 scattered upon the apex. The writer does not believe that S, rugulosum Breb. can be separated from this species, and thus it is included here. Measurements: L. 21—(32)-(34)-35u; w. 21-(32)-(34)-37u; I. 7-(10.5)-l3u. Distribution: SLP, Barry (3), Calhoun, Washtenaw, Oak- land also Ionia (Wade 1949) and Macomb (Pieters 1894); NLP, Cheboygan (N & A 1932); EUP, Alger; WUP, Houghton (N a A 1932); Isle Royale (Prescott 1937 and 1940 S, £357 ulosum). 31. Staurastrum turgescens De Not. West and West, 1912. Monogr. Brit. Desm. 4:167. P1. 126, Figs. 5, 6. This species has elliptic or elliptic-oblong semi- cells with broadly rounded angles. The lateral margins are concave, and the angles are broadly rounded in ver- tical view. The cell wall is granular, sometimes in a very irregular fashion, sometimes in concentric series around the angles. Measurements: 28-(32)-38.5u; W. 25-(32)-32.5u; I. lO-l2u. Distribution: SLP, Oakland, also Branch (N & A 1932). 32. Staurastrum cuSpidatum Bréb. West and West, and Carter, 1923. Monogr. Brit. Desm. 5:23. P1. 132, Figs. 13-15. This species has obversely triangular semicells with a single convergent or divergent spine at each angle. The elongate isthmus easily distinguishes it from.Similar species. 419 Measurements: L. (17.5)-20-31u; W. ssp. (l7.5)-18-28u; I. 5-7.8u. Distribution: SLP, Calhoun, Barry, Oakland, also Wash- tenaw (N a A 1932); NLP, Crawford, also Cheboygan (N & A 1932), (Welch 1938a); EUP, Alger, Schoolcraft; WUP, Menominee, Gogebic (2); Isle Royale (Prescott 1937). 33. var. divergens Nordst. West and West, and Carter, 1923. Monogr. Brit. Desm. 5:25. P1. 132, Figs. 16, 17. This variety is separated from the typical by the divergent spines and from var. canadense G. M. Smith by the lack of a distinct {tentation at the point of union of the two semicells. Measurements: L. ssp. 18-(21.8)-25u; L. csp. 34.8u; W. ssp. (15)-16-23.5u; W. csp. 34.8u; L. Sp. 5-(lO)-10u; I. 4.5-(5.5)-6.6u. Distribution: SLP, Calhoun, Barry, Oakland; NLP, Che- boygan (N & A 1932); EUP, Schoolcraft. 34. var. canadense G. M. Smith Smith, 1924. Wise. Geol. and Nat. Hist. Surv. 54(2):75. P1. 69, Figs. 1-3. This variety usually has divergent spines as in var. divergens Nordst. but can be distinguished from it by the distinct indentation at the point of union of the two semicells. Measurements: L. ssp. (22)—26—32u; L. esp. (36)-37-39u; 420 W. ssp. (15)-21-33u; W. csp. (35)-54-58u; L. sp. lOu; I. (4.5)-5u. Distribution: SLP, Calhoun; NLP, Cheboygan (Taft 1939). 35. var. maximum var. nov. P1. 23, Fig. 3. This variety differs from the typical and varieties of the typical, by the possession of greatly elongated Spines, the Slightly mammillate angles, and the slightly curved cell and Spines in end view. It should be com- pared with S, curvatum var. elongatum, G. M. Smith, from ‘which it differs by the indentation at the point of union of the semicells, the slightly mammillate angles, and in vertical view, the less retuse lateral margins and very slight curvature of the spines which are also longer than measurements given by Smith (1924). Measurements: L. ssp. 38u; W. ssp. 23u; W. csp. 81u; I. 5-6u; L. sp. 32u. Distribution: SLP, Barry. 36. var. coronulatum Gutw. West and West, and Carter, 1923. Monogr. Brit. Desm. 5:26. P1. 33, Fig. 1. This variety has a circle of verrucae just below the insertion of the Spines on the angles. Some authors believe that these are not verrucae but gelatinous threads from.mucilage pores. Measurements: L. 26u; W. csp. 36u; I. 5-6u. Distribution: NLP, Cheboygan (Taft 1939). 37- 38. 39- 421 Staurastrum Dickiei Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:3. P1. 124, Figs. 14, 15. This species has subelliptic semicells with a single convergent spine at each angle. The vertical view is triangular with concave lateral margins and with the broadly rounded angles bearing a single Spine. The sub- elliptic semicells separates this species from SE, £2827 canthum Lund. Measurements: L. 35-(36)-(43)-46u: W. ssp. 29-(43)-48u; W. csp. 39-(47)-59u; I. 8-11-(12)u. Distribution: SLP, Calhoun, Oakland also Macomb (Pieters 1894); NLP, Cheboygan (N a A 1932); EUP, Schoolcraft (2), Alger; WUP, Iron, Menominee; Isle Royale (Prescott 1937, 1940). var. maximum West and West 'Smith, G. M., 1924. Wise. Geo. and Nat. Hist. Surv. 57(2):76. P1. 70, Figs. 3-5. This variety is usually larger than the typical, and the sinus is acutely angled. Measurements: L. 40-69u; W. ssp. 42-73u; W. csp. 62-86u; I. 11-15u. Distribution: Isle Royale (Prescott 1940). var. rhomboideum West and West West, West and Carter, 1923. Monogr. Brit. Desm, 5:5. Pl. 129, Fig. 17. 422 This variety has rhomboidal semicells in which the lateral margins are straight in front view. Specimens from Alger County approach the fa. depressa Irenee-Marie of this variety. Measurements: L. 36-(37)-46u; W. ssp. 40-48u; W. csp. 52-55-70u; I. 8.5-lO.5-13u. Distribution: NLP, Crawford; EUP, Alger; Isle Royale (Prescott 1937). 40. var. circulars Turn. West, West and Carter, 1923. Monogr. Brit. Desm. 5:5. Pl. 129, Fig. 16. This variety is separated from typical by the almost semicircular semicells. Measurements: L. 24-(43)—50u; W. 26-(43)-45u; I. 8-(10.5)-17u. ’ Distribution: SLP, Calhoun, Washtenaw, Oakland, Jackson, also Calhoun (Pres. & Mag. 1935); EUP, Schoolcraft; WUP, Marquette; Isle Royale (Prescott 1937: 1940). 41. Staurastrum glabrum (Ehr.) Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:2. Pl. 129, Figs. 2-4. This species has cuneate, or obversely triangular semicells with a large convergent spine at each angle. In vertical view the semicells are usually triangular (the wriier's specimens were all quadrangular) with con- cave lateral margins. In addition, the spines are curved 423 (in vertical view), agreeing favorably with specimens illustrated by Prescott (1935) from Cape Cod. Measurements: L. l6-(23.5)-25u; W. ssp. 15-19-30u; W. CSp. 34.2-(43)u; I. 5-(9)-9.3u. Distribution: NLP, Cheboygan (N a A 1932); EUP, Chippewa. 42. Staurastrum connatum (Lund.) Roy and Biss. West and West and Carter, 1923. Monogr. Brit. Desm. 5:15. P1. 130, Figs. 6-8. This species is characterized by obsemicircular semi- cells with long (over 8u),erect or almost erect spines at the angles. Measurements: L. ssp. 20-29.5-(30)u; W. ssp. 20-22.5u; I. 6.5-(6.5)-9.2u. Distribution: SLP, Calhoun; NLP, Cheboygan (N & A 1932). 43. var. americanum West and West P1. 23, Fig. 4. West and West, 1896. Trans. Linn. Soc. Lond. 2nd. Ser. Bot. 5(5):255. P1. 16, Fig. 7. This variety is somewhat longer and narrower than the typical. The spines are long, slightly curved and very robust. Measurements: L. ssp. 24u; L. csp. 48u; W. 19.5u; I. 6u. Distribution: SLP, Calhoun. New records for Michigan. I 44. Staurastrgm_apiculatum Breb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:6. P1. 129, Figs. 6-8. This species has obversely subsemicircular semi- 424 cells with a small (under 6u1 almost erect spine on each angle. Measurements: L. l4-(l9)-(21.5)-29u; W. (15)-15-(21.5)- 29u; I. (4.5)-5-7u. Distribution: SLP, Calhoun; NLP, Cheboygan (N & A 1932); EUP, Schoolcraft (2); WUP, Menominee, Gogebic. 45. Staurastrum aristiferum Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:22. Pl. 132, Figs. 10, 11. This species has obversely triangular semicells that have the ventral margins indented slightly about half- way between the isthmus and the apex. The Specimens from Chippewa County have stouter and shorter spines than in the typical plant. Measurements: L. ssp. 21-(2l.5)-30u; L. csp. (36)-4o- 58u; W. ssp. (21.5)-22-24-27u; W. csp. (30)-38-45u; I. 6-6.5-(9)u. Distribution: SLP, Calhoun (Pres. a Mag. 1935); NLP, Cheboygan (N & A 1932, Welch 1936b); EUP, Chippewa. 46. Staurastrum curvatum West West, West and Carter, 1923. Monogr. Brit. Desm. 5:19. Pl. 130, Figs. 15, 16. This species has obversely triangular to sublunate semicells with a long straight divergent spine at each angle. The apices are concave. In transverse view, the cells are triangular with the acute angles each bearing 425 a long, straight, sometimes slightly curved spine. The lateral margins are retuse in this view. This species resembles superficially S, megacanthum Lund. from which it can be easily distinguished by the concave apices and the smaller size of the cell body. The spines on speci- mens from Barry are considerably shorter than typical. Measurements: L. ssp. 25-(26)-32.5u; W. ssp. 20-(26)- 35u; W. csp. (45)-64-80u; I. 54(6)-8.5u. Distribution: SLP, Barry; NLP, Cheboygan (Taft 1939). 47. Staurastrum 0*Mearii Arch. West, West and Carter, 1923. Monogr. Brit. Desm. 5:13. P1. 132, Figs. 5-8. This small species has obversely triangular semi- cells with a sharp spine at each angle. The triangular end view usually has straight Sides. This latter fea- ture and the smaller size help distinguish it from small expressions of S, dejectum Bréb. - Measurements: L. ssp. l2-17u; W. 10-18u; I. 5-8u; Sp. 4-lOu. Distribution: NLP, Presque Isle, also Cheboygan (N & A 1932). 48. var. minutum W. West West, West and Carter, 1923. Monogr. Brit. Desm. 5:14. P1. 132, Fig. 9. This variety is much smaller than the typical plant. Measurements: L. ssp. 7-8u; W. ssp. lOu; I. 5u; Sp. lOu. Distribution: Cheboygan (Welch 1938a, C. Taft, identi- fication). 426 49. Staurastrum dejectum Breb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:7. P1. 129, Fig. 9—12. This species has obversely subsemicircular or ob- versely triangular semicells. Each lateral angle has a short (2.5-5u long) divergent spine inserted as a contin- uation of the angle or rarely more in a horizontal posi- tion. The vertical view is triangular with concave lat- eral margins and with a single, short spine at each angle. The small expression of this species resembles S, O'Mearii Archer sometimes, but the latter is usually much smaller and has straight or slightly convex lateral margins in vertical view. The writer has observed no specimens from Michigan with an elongated isthmus which Smith (1924a) states is a variable characteristic of this species. Measurements: L. ssp. 18-(19)-28u; W. ssp. 17—(19)-32u; I. 5-(6.2)-8u; Sp. 2.5-10u. Distribution: SLP, Barry (3), Calhoun, Livingston also Macomb (Pieters 1894); NLP, Crawford, Cheboygan (N & A 1932, Welch 1938a); EUP, Chippewa. 50. var. inflatum West P1. 23, Fig. 5. West, West and Clrter, 1923. Monogr. Brit. Desm. 5:9. Pl. 139, Figs. 1, 2. This variety is larger than the typical and has con- vex dorsal margins. The Michigan specimens agree more favorably with Smith (1924a) than with the Wests (1923). 427 Measurements: L. 31-(32)-43u; W. ssp. 31-(34)-52u; Distribution: WUP, Gogebic, New record for Michigan. 51. Staurastrum megacanthum Lund. West, West and Carter. Monogr. Brit. Desm. 5:20. P1. 131, Figs. 7, 8. This species has obversely triangular (sometimes almost fusiform) semicells with a stout straight or slightly convergent spine at each angle. The vertical view is triangular or quadrangular with concave lateral margins. This species has a resemblance to S, Dickiei Ralfs, S, curvatum West and S, dejectum Breb., but has a stouter spine at the angles and a different semicell shape. Measurements: L. 24-(36)~50u; W. ssp. 35-(43)-57u; W. csp. 58-(64)-(70)-83u; I. 9-(10.5)-l4.5u; Sp. 7-18u. Distribution: SLP, Calhoun, Barry; NLP, Presque Isle, also Cheboygan (Welch 1938a). 52. var. scoticum West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:21. P1. 131, Figs. 9, 10. The spines on this variety are relatively longer than the typical. Smith (1924) states that the apices are concave, although West, West and Carter (1923) state that they may be straight. Measurements: L. ssp. 35-44u; W. ssp. 38-51u; W. csp. 67-lllu; I. 8-lO.5u; Sp. 19-34u. Distribution: NLP. Chebovgan (Taft 1020\. 428 53. Staurastrum granulosum (Ehrenb.) Ralfs. P1. 23, Fig. 6. Irenee-Marie, 1938. Flor. Desm. de la Reg. Mont. 1938:287. P1. 46, Fig. 9; P1. 48, Fig. 9. This species is very similar to S, lunatum Ralfs. but has distinctly convex dorsal margins in front view. The sinus is acute at the apices and widely Open to the ex- terior. The apical and lateral margins are convex and each of the angles is tipped with a short, stout spine. The vertical view is triangular with the lateral margins slightly retuse, and with each of the angles terminated by a short, stout Spine. The semicell walls are orna- mented with granules which are irregularly disposed upon the apices and face of the wall, but in concentric series around the angles. Measurements: L. 28-(28)-(30)-49u; W. 27-(32)-48u; I. 9-(10.5)-17u. Distribution: NLP, Emmet; EUP, Chippewa. New records for Michigan. 54. Staurastrum lunatum Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:29. P1. 33, Figs. 17-19. This species has semicircular semicells with a small sharp divergent spine at each angle. The vertical view is triangular with the lateral margins concave and with each of the angles ornamented with a single spine. The cell wall is uniformly covered with small granules, 429 especially in regular concentric series around the angles. The almost straight dorsal margins (in front view) and the marked concavity of’the lateral margins separates this Species from S, granulosum (Ehrenb.) Ralfs. Measurements: L. 25-(30)-39u; W. 28-(32)-43u; I. 6.5- (lO.7)-l3u. Distribution: SLP, Calhoun; NLP, Emmet; Isle Royale (Prescott 1940). 55. Staurastrum Brasiliense var. Lundellii West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:35. Pl. 135, Figs. 12, 13. This large organism cannot be confused with any other species of Staurastrum. The semicells are broadly cuneate with each of the truncate angles ornamented with three long, stout divergent spines. The vertical view is 5-6 angled with the lateral margins deeply concave. Measurements: L. ssp. 74-80u; L. csp. l20-145u; W. ssp. 63-92u; W. csp. 120-148u; I. 28-38u; Sp. 25-37u. Distribution: Isle Royale (Prescott 1937). 56. Staurastrum quadrangulare var. armatum‘West P1. 24, Fig.1. IreneeéMarie, 1938. Flor. Desm. de la Reg. Mont.:282. P1. 47, Fig. 3. This species (usually quadrangular in vertical view) has rectangular semicells with two simple spines at each apical angle. A pair of bifurcate projections occur at each basal angle with the lower part of the projections 430 often being more strongly developed. This should be compared with S, contectum var. inevolutum West, which has only a single bifurcate projection at each basal angle. Measurements: L. 22-(25)-30u; w. 25-28-29u; I. (9)—lO-12u. Distribution: SLP, Oakland. New record for Michigan. 57. Staurastrum quadrispinatum Turner West, West and Carter, 1923. Monogr. Brit. Desm. 5:38. Pl. 135, Figs. 5-7. This species is characterized by two pairs of long robust spines at each angle of the triangular semicell (in vertical view). One pair of divergent Spines is in- serted at the apical angle, and the other pair of spines which is convergent is inserted on the lateral margins (in front view). Measurements: L. ssp. (32)-33-39u; L. csp. (53)u; W. ssp. (25)-26-30.5u; W. csp. (43)u; I. 8-(10.5)-10.5u; Sp. about lOu. Distribution: NLP, Cheboygan (N & A 1932); EUP, Chippewa. 58. Staurastrum trifidum var. inflexum West and West Pl. 24,Fig.2. West and West, 1896. Trans. Linn. Soc. Lon. Bot. 2nd Ser. 5(5):258. P1. 16, Fig. 22. This organism is characterized by three (one apical, two subapical) spines at each angle. In vertical view, the triangular semicells have the angles slightly re- curved with the spines at the angle slightly twisted. #31 Measurements: L. 28.5-(34)u; W. ssp. 30.5-(32)u. W. 08p. (43)-44u; I. 9-(14)u. Distribution: EUP, Schoolcraft. New record for Michigan. 59. Staurastrum longispinum (Bail.) Arch. West, West and Carter, 1923. Monogr. Brit. Desm. 5:34. P1. 134, Fig. 1. This large species is characterized by subelliptical or subtriangular semicells with each angle possessing two large, stout, divergent spines. The vertical view is triangular with slightly concave lateral margins and broadly rounded angles, each angle being ornamented with two stout spines. Measurements: L. 90-l20u; W. ssp. 73-lOOu; I. 36-41u; Sp. 9.5-32.5u. Distribution: NLP, Cheboygan (Taft 1939). 60. var. bidentatum (Wittr.) West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:34. Pl. 134, Figs. 2, 3. The Spines are smaller and the apex is less convex than in the typical. Measurements: L. 80-90u; W. ssp. 75-85u; I. 30-35u; Sp. 7-lOu. Distribution: NLP, Cheboygan (Taft 1939). 61. Staurastrum aviculoides Gronbl. fa. P1. 24, Fig. 3. Gronblad, 1938. Bot. Not.:59. Pl. 2, Fig. 11. This Species has subtriangular semicells with two small, almost erect, spines inserted at each of the apical 432 angles. In and view, the triangular semicells have con- cave lateral margins. The Michigan specimens from Oak- land County have more robust and sharply curved apical spines, and were smaller than the typical. The lateral margins in front view were also undulate in contrast to the straight lateral margins shown by Gronbl. (1938). Measurements: L. (28)-42u; W. (32)-53u; I. l7u. Distribution: SLP, Oakland. New record for Michigan. I 62. Staurastrum avicula Breb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:40. Pl. 133, Figs. 8-10, 12. This species has subelliptical or subtriangular semicells with each apical angle possessing two short spines, one above the other. In vertical view, the semi- cells are triangular with concave lateral margins and with spines at each angle. The cell wall is finely granulate, the granules being arranged in concentric rings around the angles. Measurements: L. 29-(30)-34.5u; W. ssp. (30)u; W. CSp. 35u; I. 9-(10.9)-llu. Distribution: SLP, Calhoun, also Wayne (Campbell 1886), Macomb (Pieters 1894), Branch (N a A 1932); NLP, Cheboygan (N a A 1932); EUP, Schoolcraft; Isle Royale (Prescott 1940), Alger (fa.). 63. var. subarcuatum (Wolle) West P1. 24, Fig. 4. West, West and Carter, 1923. Monogr. Brit. Desm. 5:41. P1. 133, Fig. 11. 433 This variety has obversely triangular semicells with a nearly straight apical margin. Measurements: L. 20-(26)-(30)-32u; W. 30-(30)—40-(4l)u; I. 8.5-(12)—(12.5)-l4u. Distribution: SLP, Barry, Washtenaw; NLP, Roscommon, Emmet, Presque Isle; EUP, Delta; WUP, Houghton (2). New records for Michigan. 64. var. coronulatum var. nov. P1. 24, Fig. 5. This variety differs from the typical in the poss- ession of verrucae on the apices. In vertical view, there is a lateral series of four verrucae just within the lateral margin. In addition, there is a second lat- eral series of four verrucae within the first series, the secondary series forming a triangular pattern. This organism should be compared with S, rugosum Irénee-Marie from which it differs in the possession of two spines which are inserted subapically on the angles. S, rugosum has short lateral processes which are trifid at the ends. In addition, this variety has (in transverse view) a linear series of four verrucae just within each lateral margin, and the granules upon the angles are much smaller than those shown by Irénee-Marie. Measurements: L. 32u; W. csp. 38u; I. 10.5u. Distribution: WUP, Menominee. 65. Staurastrum subcruciatum Cooke and Wills P1. 24, Fig. 6; P1. 25, Fig. 1. The obversely triangular to lunate semicells of this Species have the angles developed very slightly 434 into short divergent processes which are terminated by two divergent spines that lie in the same plane. The cell wall is granulate, the small granules being arranged in concentric series around the angles. The vertical view is triangular with concave lateral margins, and with the angles slightly extended into short processes which are terminated by two large spines. Specimens from Barry County are similar but larger than the typical, but those from Marquette and Presque Isle Counties have the processes reduced or completely lacking and should probably be considered a distinct forma. Measurements: L. (28)-30-(42)u; W. 33-(33)-35-46u; I. 7.5-(10.5)u. Distribution: SLP, Barry; NLP, Presque Isle; WUP, Mar- quette, New records for Michigan. 66.. Staurastrum subdenticulatum Nordst. fa. P1. 25, Fig. 2. Nordstedt, 1888. Kongl. Sv. Vet. Akad. Handl. 22(8):39. P1. 4, Fig. 14. This species has hexagonal semicells with the lat- eral margins bearing two stout spines (one convergent, the other divergent). In vertical view the triangular semicells have slightly concave margins and acutely rounded angles with one spine visible. Large granules are arranged in three concentric series around the angles, the remaining cell wall being smooth. Nordstedt (1888) illustrations Show a triangular pattern of granules on 435 the apices which was lacking in the Michigan specimens. The spines in the writer's specimens are also more ro- bust. Nordstedt (1895) questions this species as possibly being an expression of S, avicula. Measurements: L. 40-(43)u; W. ssp. 40; W. csp. (49)u. Distribution: EUP, Delta. New record for Michigan. 67. Staurastrum Simonyii Heimerl. West, West and Carter, 1923. Monogr. Brit. Desm. 5:45. Pl. 135, Figs. 1-4. This small species has elliptic to subfusiform semicells. The truncate lateral margins and also the apices have 2-4 Short spines. The angles sometimes have_ 2-3 concentric series of sharp granules or denticulations. The triangular apical view shows variable lateral margins and obtusely rounded angles with 2-4 spines. In addition, there is a series of 2-4 spines just within the lateral margin, the middle two the largest of the four present. Measurements: L. csp. 18-(23)-26u; W. ssp. 18-(23)-24u; W. csp. 22-25u; I. 6-(6.5)-10u. Distribution: SLP, Barry; NLP, Cheboygan (N a A 1932); EUP, Chippewa, Schoolcraft; WUP, Gogebic (2), Baraga (2), Houghton. 68. Staurastrum minnesotense Wolle Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):81. P1. 71, Figs. 14, 15. This very large species is characterized by the presence of two large spines at each angle which are 436 larger than the two subapical pairs. Measurements: L. ssp. 84-(94)-104u; L. csp. 99-(118)-145u; W. ssp. 82-88-112; W. csp. 105-(105)-172u; I. 20-(42)- 42.5u. Distribution: SLP, Barry; Isle Royale (Prescott 1937, 1940. 69. Staurastrum setigerum Cleve. P1. 25, Fig. 3. West, West and Carter, 1923. Monogr. Brit. Desm. 5:52. P1. 136, Figs. 13, 14. This species has elliptical semicells with the apices often flattened. The extreme angles have two (usually three) -5 stout spines in a vertical row. In addition, there are smaller, more slender spines arranged around the angles in concentric series which are not always dis- tinct. In vertical view, the semicells are triangular, with three stout superimposed spines at the terminus of the angles. Smaller and more delicate spines are ar- ranged obscurely around the angles in concentric series. Measurements: L. ssp. 42-(47)-56u; W. ssp. 27-40-55u; L. (10.5)-11-20u; Sp. 5-(11)-20u. Distribution: SLP, Oakland; WUP, Houghton. New records for Michigan. 70. var. brevispinum G. M. Smith P1. 26, Fig. 1. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):80. P1. 71, Figs. 9-13. This variety is slightly smaller than the typical, 437 and also has four stout spines quadrately arranged at the angles. In addition, there are one or two spines on thekdorsal margin internally from the lateral spine. The body has two transverse rows of smaller spines. Measurements: L. (38)-39-4lu; W. ssp. 35-(38)-40u; W. csp. 42-(47)-53u; I. (lO.5)-12-14u. Distribution: SLP, Barry. New record for Michigan. 71. var. occidentale West and West Smith, 1924. Bull, Wisc. Geo. and Nat. Hist. Surv. 57(2):80. P1. 71, Figs. 1-4. This variety has the semicells more compressed than the typical. In vertical view, there are only two mar- ginal spines. Measurements: L. ssp. 32-33u; L. csp. 41-45u; W. ssp. 41-42u; W. csp. 57-63u; I. 11.5-12.5u; Sp. (large stout) lO-l2.5u, (short delicate) 4-9u. Distribution: NLP, Cheboygan (N a A 1932). 72. var. pectinatum West and West P1. 26, Fig. 2. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):80. P1. 71, Figs. 5-8. This variety differs from the typical in possession of longer spines. In vertical view, the marginal spines are restricted to regions of the angles. Measurements: L. ssp. 34-(42)-54u; L. csp. 44-(52)-64u; W. ssp. 31-(46)-49u; W. csp. 46-(67)-67u; I. 6.5-l7u. Distribution: NLP, Presque Isle. New record for Michigan. 438 73. Staurastrum spiculiferum G. M. Smith fa. P1. 26, Fig. 3. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):82. P1. 71, Figs. 16-20. This small Species has hexagonal rectangular semi- cells with subconvex or subconcave apices. The lateral margins are truncate with either one or two spines at the basal angle, and one spine at the superior angle. In vertical view, the triangular semicell has two spines (one near each angle) on the margin, and two spines with- in the margin just behind the angle. The Michigan speci- mens from Livingston County resemble figures 19 and 20 on P1. 71 shown by Smith (1924), but there are three long spines at the basal lateral angle, and three long spines at apical lateral angle. In addition, there is an apical linear series of short spines within each lat- eral margin (in vertical view). The writer's specimens were slightly smaller than the typical measurements. Measurements: L. ssp. (21)-23-25u; L. csp. (25.5)-29-45u; W. ssp. 20-(21.3)-24u; W. csp. (24.5)-30-40u; I. 6.5- (6.5)-8.5u. Distribution: SLP, Livingston. New record for Michigan. 74. Staurastrum hystrix Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:60. Pl. 136, Fig. 1. This species has elliptic oblong semicells with 2-3 spines at the bluntly rounded angles. In addition, there -:o—— 439 are 3-4 spines in a series just back from the angle. In the vertical view, the semicells are triangular, with slightly concave lateral margins and obtusely rounded angles. There are 3-4 spines at the apex of the angle, and about three on or within each side of the lateral margin just behind the apex of the angle. Measurements: L. ssp. 25-(27)u; W. ssp. 20-(23)u; I. 6.5-(10.5)u; Sp. (3)-3-4u. Distribution: NLP, Cheboygan (N a A 1932) (Welch 1938a); EUP, Chippewa. 75. Staurastrum Ravenelli Wood West, West and Carter, 1923. Monogr. Brit. Desm. 5:70. Pl. 138, Figs. 7, 8. This species has subelliptical to subpyramidate- truncate semicells. The vertical view is triangular with nearly straight lateral margins. The cell wall is covered with granules which are often emarginate and spinate. Measurements: L. 28-36u; W. 28-32u; I. 18-24u. Distribution: SLP, Wayne (Campbell 1894), Washtenaw (West and West 1898). 76. Staurastrum echinatum Breb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:56. Pl. 137, Fig. 12. The broadly elliptical semicells of this species are covered with short spines which have dilated bases. 1:40 Measurements: L 33a; W 291; I 1;.5u; L 9?. hdet 1.5s. Distribution: SLP, Macomb (Pieters 1894); NLP, Cheboygan (N & A 1932). 77. Staurastrum teliferum Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:58. Pl. 136, Figs. 2-6. This species has broadly elliptic semicells with numerous stout spines arranged near the angles. The vertical view is triangular with concave lateral margins and broadly rounded angles. The stout spines are ar- ranged mostly around the angles, being lacking in the middle of the lateral margin and in the center of the apex. Measurements: .L. ssp. 32-56u; L. csp. 40-64u; W. ssp. 27-(29)-37u; W. csp. (40)-40-45u; I. 15u. Distribution: SLP, Macomb (Pieters 1894); NLP, Cheboy- gan (N & A 1932); EUP, Chippewa. 78. Staurastrum Bohlinianum Schmidle fa. P1. 26, Fig. 5. Schmidle, 1898. Bih. t. Kongl. Sv. Vet. Akad. Handl. 24:53. Pl. 3, Fig. 3. This small species has elliptic semicells with broadly rounded angles. The semicell bodybespecially the region of the angles, is ornamented with concentric series of acute granules and the processes are termin- ated by four smallspines. In vertical view, the semi- cells are triangular with slightly concave lateral mar- 441 gins. The central portion of the apex is smooth. The sinus on the Michigan specimens have a less acute apex, and the lateral margins (in vertical view) have more strongly developed granules than the typical. Measurements: L. 20-(21.5)-24u; W. 20-22-(25)u; I. (8.5)u. Distribution: EUP, Chippewa. New record for North America. 79. Staurastrum muricatum Breb. P1. 26, Fig. 4. West, West and Carter, 1923. Monogr. Brit. Desm. 5:67. P1. 138, Fig. 9; Pl. 139, Figs. 1, 2. The subelliptical to subreniform (rarely truncate- pyramidate) semicells have the cell wall covered with minute conical granules. The semicells are triangular in end view, with straight or slight concave lateral margins. Measurements: L. (45)-46—62.5u; W. (38)-40-55u; I. (10.5)- l2—2lu. Distribution: EUP, Schoolcraft; WUP, Houghton, Gogebic. New record for Michigan. 80. Staurastrum saxonicum Bulnh. West, West and Carter, 1923. Monogr. Brit. Desm. 5:54. P1. 137, Fig. 7. The broadly oval semicells with broadly rounded angles of this species are covered regularly by short, acute Spines except in the center of the apices. The vertical view is triangular (rarely 4-5 angular) with slightly convex lateral margins and broadly rounded angles. This 442 species is longer and has more broadly oval semicells than S, Brebissonii Archer. Measurements: L. ssp. 77—79u; L. CSp. 85-86u; W. ssp. 58-65u; W. csp. 72-74u; I. 21-22u; Sp. 3-8u. Distribution: NLP, Cheboygan (N & A 1932). 81. Staurastrum polytrichum (Perty) Rabehn. West, West and Carter, 1923. Monogr. Brit. Desm. 5:53. Pl. 136, Figs. 8-10. This species has elliptical or subelliptical semi- cells covered with fairly long acute spines which are arranged around the angles in irregular concentric series and in the longitudinal rows upon the cell body, S,ngg¢ ticosum Delp. cannot be clearly differentiated from S, polytrichum_and therefore is included here. Measurements: L. ssp. 48-67u; L. csp. 54-80u; W. ssp. 41-48u; W. csp. 50-70u; I. 15-22u; Sp. 5-llu. Distribution: NLP, Cheboygan (N a A 1932, also Cheboygan and Emmet, S, senticosum); WUP, Houghton (N a A 1932); Isle Royale (Prescott 1940). 82. Staurastrum Brebissonii Arch. West, West and Carter, 1923. Monogr. Brit. Desm. 5:86. Pl. 137, Figs. 4, 5. The elliptic or elliptic-fusiform semicells of this species have acutely rounded angles. The cell wall is wh'ds 0" covered with short acute spines,in concentric series around the angle where they may be longer and more num- 443 erous. The vertical view is triangular with slightly concave lateral margins and acutely rounded angles. Spines are lacking in the central region of the semi- cell apices. Measurements: L. ssp. 34-(41)-48u; W. ssp. 40-(45)-62u; I. (13)-13u; Sp. 2.5u. Distribution: EUP, Schoolcraft, Delta; WUP, Houghton, Gogebic; Isle Royale (Prescott 1940). 83. var. maximum Cedercreutz Cedercreutz, 1932. Mem. Soc. pro Faun. et Fenn. 7:245. Text Figures 14, 15. , This is much larger than the typical. Measurements: L. 87u; W. 85.5u; I. 4u. Distribution: Isle Royale (Prescott 1937). 84. Staurastrum gladiosum Turner West, West and Carter, 1923. Monogr. Brit. Desm. 5:57. Pl. 137, Figs. 1, 2. This species has elliptic-reniform semicells with the dorsal and ventral margins about equally convex. The wall is uniformly covered with short spines which are in vague concentric series around the angles. The apical view is triangular with slightly concave lateral margins and broadly rounded angles. Measurements: L. ssp. 37.5-(4l)-43u; L. csp. 44.8-(47)-52u; W. ssp. 35-40u; W. csp. 44-50u; I. 10-17.5u. Distribution: SLP, Barry, Jackson; NLP, Cheboygan (N & A 444 1932, Welch 1936b); EUP, Chippewa; WUP, Houghton, Goge- bic (2); Isle Royale (Prescott 1937, 1940). 85. Staurastrum pilosum (Naeg.) Archer P1. 27, Fig. 1. West, West and Carter, 1923. Monogr. Brit. Desm. 5:63. P1. 138, Figs. 1-3. There is some question as to whether this species really exists, and if it does, as to what the distinguiSh- ing characteristics are. One specimen from Gogebic County agrees rather well with the organisms illustrated by West, West and Carter (1923), and Irénee-Marie (1938). According to the former, the semicells are subelliptic or subfusiform with acutely rounded angles, and the cell wall is covered by numerous delicate spines which are arranged in concentric rings around the angles. The vertical view is triangular with concave margins and acutely rounded angles. Measurements: L. ssp. (39)-42.5-44u; W. 38-(39)~47u; I. ll-(l2)u; Sp. 2u. Distribution: WUP, Gogebic. New record for Michigan. 86. Staurastrum maamense Archer West, West and Carter, 192°. Monogr. Brit. Desm. 5:75. Pl. 139, Fig. 10. This species has semicircular or subpyramidate semi- cells with the lateral margins bearing 4-5 emarginate verrucae. The apical margins are flattened. The ver- tical view is triangular with smooth, concave lateral margins and broadly rounded or tricrenate angles. 445 Measurements: L. 33-(33)-42u; W. 28-(30)-33u; I. 10- (ll)-13u. Distribution: SLP, Barry (2), Oakland, also Calhoun (Pres. & Mag. 1935); Isle Royale (Prescott 1937, 1940). 87. var. atypicum Magnotta Prescott and Magnotta, 1935. Pap. Mich. Acad. Sci. Arts and Letters. 20:164, P1. 26, Figs. 7, 8. This variety is distinguished from the typical in the possession of single or double Spines (which are extensions of verrucae), at the basal angle of the semi- cells. Measurements: L. (39)-40-41.8u; W. (34)437.5)-38.5u; I. (10.5)-l3.5u. Distribution: SLP, Calhoun, also Calhoun (Pres. & Mag. 1935)- 88. Staurastrum spongiosum Bréb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:76. P1. 140, Fig. 4. This very characteristic species has subpyramidate- truncate to trapeziform semicells which are ornamented by 8-10 emarginate processes along the margins and about six similar processes across the face of the semicell. The vertical view is triangular with the straight or slightly convex lateral margins ornamented with four emarginate verrucae. The angles are provided with a verrucae at the apex. In addition, there are three pairs 446 of verrucae arranged across the angle and decreasing in size toward the apex. Measurements: L. 45-(56)-65u; W. 42-(43)-55u; I. 12- (l3.5)-19u. Distribution: NLP, Roscommon, Crawford, Emmet, also Cheboygan (N & A 1932). 89. var. Griffithsianum (Naeg.) Lagerh. West, West and Carter, 1923. Monogr. Brit. Desm. 5:78. Pl. 140, Fig. 15. This variety has the sinus open toward the extremi- ties and has in vertical view, a deep,rounded and dis- tinct concavity between the middle processes on each lateral margin. Measurements: Same as typical. Distribution: NLP, Cheboygan (N & A 1932). 90. var. perbifidum W. West fa. spinosa Irenee-Marie P1. 27, Fig. 2. Irénee-Marie, 1938. Flor. Desm. de la Reg. Mont.:29l. P1. 51, Fig. 11. This form is characterized by the verrucae being bifid spined. The basal angles of the semicells are Slightly projected, each extension having several small spines in addition to a strong bifurcate projection. This forma may be merely within the range of environ- mental variation of the var. perbifidum, Measurements: L. (44.5)-50u; W, (47)-53u; I. (ll.5)-12.5u. Distribution: NLP, Emmet. New record for Michigan. 447 91. Staurastrum cornutum Archer West, West and Carter, 1938. Monogr. Brit. Desm. 5:31. P1. 133, Fig. 16. This species has oval or hexagonal semicells with a strong simple or bifid spine on each lateral margin. The apices are ornamented with a series of emarginate granules or verrucae as in the lower lateral margins. There may also be a subapical row of granules or verrucae between the processes. The transverse view is triangular with slightly concave lateral margins. The angles each have a stout spine and are also ornamented by 2—3 con— centric rings of emarginate granules or verrucae. Within the lateral margin there are one or two linear series of granules or verrucae. In addition, there may be a series upon the lateral margin between the angles. This latter series is reduced to two granules, one each near the angles in the writer's specimens. Measurements: L. 27-35-40u; W. ssp. 27-33u; W. csp. 44-50.7u; I. (6.5)-8-15.6u; Sp. 9-l2u. Distribution: EUP, Schoolcraft, Delta; Isle Royale (Prescott 1937). 92. .fa. reductum fa. 22!: P1. 27, Fig. 3. This organism.can be separated from the typical by the presence of a single poorly developed convergent spine on each lateral margin. Otherwise the cell shape and ornamentation agree with the typical. 448 Measurements: L. 32u; W. ssp. 27u; W. csp. 33u; I. 10.5u. Distribution: EUP, Schoolcraft. 93. Staurastrum sexcostatum var. productum W. West West, West and Carter, 1923. Monogr. Brit. Desm. 5:148. Pl. 150, Fig. 15. This species has elliptical semicells with short blunt processes which have a circle of six granules at their apices, and which are ornamented with concentric circles of granules. The apices are granulate and the base of the semicells haste transverse row of granules. The vertical view is hexagonal with short, truncate pro- cesses and concave lateral margins. The processes have several series of granules, and the apices have Several Series of emarginate granules or verrucae inside the lat- eral margin following the contour of the semicell. Measurements: L. 36-(38)-43u; W- (38)-40-43u; I. 12.5-(15)-17.5u; Distribution: EUP, Gogebic, also Marquette (Pres. and Mag. 1935); Isle Royale (Prescott 1937, 1940). 94. Staurastrum laeve Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:92. Pl. 341, Figs. 1-3. This species has elliptical or subsemicircular semicells with two smooth apically bifid processes lying in the same plane at each angle. The cell wall is smooth. The vertical view is 3-5 angled with the lateral margins ——._—- _~——‘-'- : 449 concave and with the angles lobed and ornamented with two short bifid processes. Measurements: L. csp. l8-27.5u; W. l4-28u; I. 7-lOu. Distribution: SLP, Washtenaw (Johnson 1895). 95. Staurastrum inconspicuum Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:86. Pl. 141, Figs. 4-7; P1. 142, Fig. 8. This small species has approximately quadrangular semicells with small, short, outward, divergent processes that suddenly become narrowed and upward directed, ending in smooth truncate apices. The vertical view is 3-6 angular. Measurements: L. ssp. 12-l6u; L. csp. 15-(15)-26u; w. 12.5-(15)-26u; I. 5.5-(6.5)-9u. Distribution: SLP, Calhoun; NLP, Cheboygan (N a A 1932). 96. Staurastrum brachiatum Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:88. Pl. 141, Figs. 14, 15; Pl. 142, Figs. 1-7. This smoothawalled species has triangular semicells with about, hollow, divergent processes which are bifid: or trifid at the tips. In vertical view, the semicells are 3-5 angular with concave lateral margins and with a stout process arising at each angle. The two semicells may be twisted at the apices. This Species is easily separated from.SSSIaevispinum by the bifid or trifid F processes. 450 Measurements: L. 27-(32)-55u; w. 15-(43)-57.5u; I. 5-8.5-14u. Distribution: NLP, Cheboygan (N & A 1932, Welch 1936a, 1936b, 1938b); EUP, Chippewa, Schoolcraft; WUP, Gogebic. 97. var. ma or var. 22!: P1. 27, Fig. 4. This variety is about twice as large as the typical, and has the trifid or quadrifid apices of the processes further subdivided. Measurements: L. 75u; W. 75u; I. l7u. Distribution: EUP, Chippewa. 98. Staurastrum sublaevispinum. W. West West, West and Carter, 1923. Monogr. Brit. Desm. 5:91. Pl. 141, Fig. 19. This species has semicells composed of three very stout smooth parallel-walled processes with conical apices arising from a very reduced semicell body. The processes with the conical apices easily distinguish this species from S, brachiatum Ralfs. Measurements: L. 20-25u; W. 30-37u; I. 7-7.5u. Distribution: NLP, Cheboygan (Taft 1939). 99. Staurastrum irregulare West West, West and Carter, 1923. Monogr. Brit. Desm. 5:150. Pl. 149, Fig. 7. This very small,often twisted’biradiate species has inversely trapeziform semicells with short diverging pro- cesses. The cell wall has a truncate and scrobiculate 451 process in the middle of each semicell. This latter feature distinguishes it from S, tetracerum. Measurements: L. SSp. 9.4—9.6u; L. csp. 15.3-18.2u; W. CSp. 13.5-17.3u; I. 4.8-7.5u. Distribution: SLP, Washtenaw (West and West 1898). 100. Staurastrum leptocladum Nordst. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):102. P1. 78, Fig. 1-7. I This biradiate species is characterized by a sub- campanulate semicell with a tumid apex and an inflated base. The processes are very long and typically are first divergent and then upwardly curved. The apices hauea single subapical spine and bases of the semicells usually have a transverse row of granules. Measurementsgz L. ssp. 30-(32)-(43)-48u; L. csp. (54)- 56-95u; W. ssp.ll-2lu; W. csp. 67-(84)-(97)-l20u; I. 4.5-(8)-11u.3 Distribution: SLP, Calhoun, Barry, Clinton; EUP, School- craft; Isle Royale (Taylor 1935, Prescott 1940). 101. var. insigne West and West Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):103. P1. 77, Fig. 15; P1. 78, Figs. 8-11. This variety differs from the typical in possessing crenulations or verrucae along the lateral margins be- tween the basal swelling and the base of the process. The subapical spine of the typical is replaced by a trans- 452 verse row (4-6) of verrucae. Specimens from Calhoun County lack the transverse row, possessing one subapical elevation similar to the variety denticulatum G. M. Smith, andiin addition several apical elevations. Measurements: L. ssp. 36-42-(43)u; L. csp. 55-(6dFlOOu; W.ssp. 20-26u; W. csp. 86-(96)-110u; I. 6-8u. Distribution: SLP, Calhoun; Isle Royale (Prescott 1940). 102. Staurastrum grallatorium Nordst. P1. 28, Fig. 1. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):100. P1. 77, Figs. 3-5. This biradiate Species has narrowly campanulate semicells with truncate apices (with three emarginate verrucae). The parallel or slightly divergent processes have sharply crenulate Slightly tapered margins and are bifurcate at apices. This species is easily separated from S, Johnsonii West and West by the parallel bifur- cate processes and the lack of subapical verrucae. Measurements: L. ssp. 32-(34)-34u; L. csp. 42-48u; W. ssp. 20u; W. csp. (65)-69-86u; I. 8.5-9u. Distribution: NLP, Roscommon, Emmet; EUP, Schoolcraft (2). New records for Michigan. 103. var. forcipigerum Lagerh. P1. 28, Fig. 2. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):101. P1. 77, Figs. 6, 7. This variety has trapeziform semicells which possess two divergent spines upon the truncate apex. The lateral 453 processes have crenulate margins and are unequally bi- furcate at the apices. Measurements: L. ssp. 38-48u; L. csp. 45-57-(60)u; W. ssp. 21-33u; W. csp. 46-(65)-86u; I. 7.5-9-(9.5)u. Distribution: EUP, Schoolcraft. New record for Michigan. 104. Staurastrum natator West P1. 28, Fig. 3. West, West and Carter, 1923. Monogr. Brit. Desm. 5:149. Pl. 147, Fig. 7. This biradiate Species has subrectangular or sub- trapeziform semicells with long, slightly curved and di- vergent processes. Ornamentation consists of three tri- spinate verrucae on the apices, 6-8 granules venclosing one or two other granules on the central region of the semicell wall and a transverse row of granules at the base of the semicells. Measurements: L. ssp. 32-(32)-38.5u; L. csp. 53-(65)- 75u; W. ssp. 11-25u; W. csp. 57-(86)-88u; I. 8-(10.5)- 12.5u. Distribution: SLP, Barry; EUP, Alger, Schoolcraft. New records for Michigan. 105. Staurastrum brachioprominens Boerg. Boergesen, 1890. Vid. Medd. f. Nat. For.:952. Pl. 5, Figs. 52. This biradiate species has obversely triangular semicells with undulate apices and biundulate lateral margins. The lateral angles projecting into long, 453 slightly attenuated, divergent processes Which are den- ticulate and terminated by three small spines. The orna- mentation consists of three transverse rows of granules at the base of the semicells and a subapical row of about seven granules and minute spines on the apical un- dulations. The latter feature is probably tridentate verrucae. Measurements: L. 30u; W. 72u; I. llu. Distribution: NLP, Cheboygan (N a A 1932). 106. Staurastrum Chaetoceras (Schroeder) G. M. Smith Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):99. P1. 76, Figs. 21-24; P1. 77, Fig. 1. This biradiate species has obversely triangular semi- cells with long, divergent processes which are ornamented with concentric rings of minute granules and terminated by four small teeth. The cell body usually has a few scattered subapical granules. The vertical view is nar- rowly elliptic (rarely triangular) with long processes. Measurements: L. ssp. 19-22-(25)u; L. csp. 46-(65)-89u; W. ssp. 16-21-22u; W. csp. 65-(65)-89u; I. 5.5-6.5-7u. Distribution: SLP, Ionia (Wade 1949). 107. Staurastrum Johnsonii West and West Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):104. P1. 79, Figs. 1-6. This biradiate species has subcampanulate semicells with inflated bases. The processes have crenulate margins, 454 are slightly attenuated, and terminate in three Spines. The ornamentation consists of 5-7 subapical verrucae, a secondary transverse row of granules or verrucae just below the subapical row, and two transverse rows of gran- ules at the inflated bases of the semicells. Measurements: L. 38.5-49—85u; W. ssp. l3-30u; W. CSp. 79-99-110u; I. 8-(10.5)-12u. Distribution: SLP, Calhoun, Barry, Oakland, also Wash- tenaw (Johnson 1894, S, leptocladum, West and West 1898); NLP, Crawford; EUP, Alger; WUP, Marquette, Menominee, Gogebic. 108. var. depauperatum G. M. Smith P1. 29, Fig. 4. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):105. P1. 79, Figs. 7-11. This variety differs from the typical in having a less pronounced basal swelling and a reduced secondary subapical row of granules, and by lacking a transverse row of granules at the base. Measurements: L. ssp. 32-(38)-52u; L. csp..40-86u; W. ssp. 16-30u; W. csp. 72-(93)-l25u; I. 8-lO.5u. Distribution: SLP, Oakland, Barry; EUP, Schoolcraft. New records for Michigan. 109. Staurastrum anchora West and West P1. 29, Fig. 1. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):101. P1. 77. Figs. 8, 9. This biradiate Species has campanulate semdcells 455 with very slightly inflated bases. The parallel or slightly convergent processes have crenulate margins and are tipped by three divergent Spines. The apices of the semicells are flattened and ornamented with a single subapical transverse row of 8-10 emarginate verrucae. Measurements: L. 65-(75)-76u; W. ssp. 22-58u; W. csp. 113-(117)-l62u; I. 12-15-(17)u. Distribution: SLP, Barry, Oakland. New records for Michigan. 110. Staurastrum bicorne Hauptfl. West, West and Carter, 1923. Monogr. Brit. Desm. 5:117. Pl. 143, Fig. 17. The subtriangular semicells of the species are bi- radiate with the parallel or convergent processes gradu- ally tapered and terminated by three spines. The apices are flattened and bear two transverse rows of 8-10 emar- ginate verrucae. Measurements: L. 52-(53)-71u; W. ssp. l9-27u; W. csp. (69)-72-93u; I. 10-13.4-(15)u. Distribution: NLP, Emmet, also Cheboygan (N & A 1932). 111. Staurastrum contortum G. M. Smith Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):98. P1. 76, Figs. 17-20. This biradiate species has obversely triangular semicells which are twisted at right angles to each other. The processes are long, attenuated and divergent. 456 Measurements: L. ssp. l2u; L. csp. 36-67u; W. ssp. 10.5-12u; W. csp. 44-119u; I. 6u. Distribution: NLP, Cheboygan (Taft 1939). 112. Stagrastrum.tetracerum Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:118. Pl. 149, Figs. 2, 3. This small biradiate species has rectangular semi- cells with long divergent processes. The semicells are often twisted at the isthmus. Measurements: L. ssp. 7-(8)-10u; L. csp. 18-(22)-28u; W. ssp. 7-(8.5)-9u; W. csp. 18-(18)-32u; I. 2.5-(3)-6u. Distribution: SLP, Calhoun, Barry, Oakland; NLP, Emmet, also Cheboygan (N a A 1932): EUP, Schoolcraft, Mackinac; WUP, Menominee, Marquette; Isle Royale (Prescott 1940). 113. Staurastrum cyrtocerum var. compactum West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:136. P1. 149, Fig. 10. This organism has cup-shaped semicells in which the lateral margins are much more convex than the apical mar- gin. The processes are slightly attenuated, stout, con- vergent and tipped with short spines. The vertical view is triangular or quadrangular with concave lateral mar- gins and with the angles projected into short, stout processes tipped with three short spines. The processes are usually twisted (all in same direction). The cell wall is granulate. The granules are arranged in concen- 457 tric series around the angles, and in longitudinal rows upon the body. The apices are ornamented with an intra- marginal series of verrucae. Measurements: L. 36; W. csp. 40u; I. llu. Distribution: WLP, Houghton (N & A 1932). I 114. Staurastrum controversum Breb. P1. 28, Fig. 4. West, West and Carter, 1923. Monogr. Brit. Desm. 5:162. P1. 154, Figs. 1-4. This species is characterized by elliptic or fusi- form semicells in which the angles are projected into laterally twisted and slightly convergent processes. The processes are ornamented with 3-4 concentric series of granules and tipped by 3-5 spines. The apical view is triangular (rarely more than 4-5 angular), with concave lateral margins and with processes twisted in the same direction. Within the lateral margin there is a linear series of bifid spines or emarginate granules which are often displaced by twisting of the cell. Sometimes there is secondary series upon the lateral margin. Measurements: L. 26-(38)-(44)-65u; W. 28-(60)-(65)-75u; I. 6.8-(10.5)-l2-(l3)u. ' ’ Distribution: SLP, Barry; EUP, Schoolcraft; WUP, Mar- quette. New record for Michigan. 115. Staurastrum hexacerum. (Ehrenb.) Wittr. West, West and Carter, 1923. Monogr. Brit. Desm. 5:138. Pl. 142, Figs. 11-14. 458 This species has fusiform or subtriangular semi- cells with short, tapering processes which are tipped with three spines. The transverse view is usually tri- angular with slightly concave lateral margins and short, attenuated processes. The cell wall is granulate, the granules in concentric series around the angles and some- what reduced upon the apices and body. The processes are longer than typical in the Mackinac County specimens. A form from.Nenominee County is slightly longer and is more uniformly granulate than typically and has the semi- cells slightly twisted at the isthmus. Measurements: L. 18-(25)-28-(32)u; W. csp. 20.5-34-(35)- (40)u; I. 4.5—8u. Distribution: NLP, Cheboygan (N & A 1932); EUP, Mack- inac; WUP, Gogebic (2); Menominee; Isle Royale (Prescott 1940). 116. Staurastrum affine West and West fa. P1. 28, Fig. 5. West, West and Carter, 1923. Monogr. Brit. Desm. 5:128. P1. 142, Fig. 23. This species typically possesses the following char- acteristics. The semicells are elliptic-subsemicircular with both margins convex, the lateral ones especially so. The processes are short and divergent, and are terminated with four short spines. There are 2-3 concentric series of denticulations about the processes just within the apical spines. The semicells are triangular in vertical 459 view with slightly concave lateral margins and short denticulate processes. The cell wall is granulate. A single specimen from Gogebic County, for which the measurements are unfortunately unavailable, agrees well with this description but differs primarily in the much shorter processes, the less convex dorsal margin in front view, and the straight lateral margins in vertical view. In addition, the cell wall appeared smooth. Measurements: (Typical) L. 36-40u; W. ssp. 28-33u; W. csp. 44-45u; I. 10-10.5u. Distribution: WUP, Gogebic. New record for Michigan. 117. Staurastrum suggracillimum West and West P1. 28, Fig. 6. West and West, 1896. Trans. Linn. Soc. of Lon. Bot. 2nd Ser. 5(5):263. P1. 17, Figs. 3, 4. This small species is characterized by broadly cun- eate semicells with concave apices. The processes are very long, about horizontal, undulate, the same width throughout and terminated by three divergent spines. The vertical view is triangular with lateral margins straight or concave and with the long narrow processes terminated with three divergent spines. The angles of the one semicell may alternate with those of the other semicell. Measurements: L. (9)-10.5-15.5u; W. ssp. l2-13u; W. csp. 40-44-60u; I. 4.8-(5)-6u. Distribution: EUP, Schoolcraft. New record for Michigan. 460 118. Staurastrum iotanum' Wolle West and West and Carter, 1923. Monogr. Brit. Desm. 5:121. Pl. 149, Fig. 1. This very small Species has subrectangular semicells with angular bases. The processes are long and divergent, undulate and with emarginate apices. The vertical view is triangular with straight lateral margins and long un- dulate processes. Measurements: L. ssp. 8-lOu; L. csp. 12-(17.5)—22u; W. ssp. 6-10u; W. csp. 12-(22)-23u; I. 3-(5)-6u. Distribution: SLP, Calhoun, Barry; NLP, Crawford, Emmet, also Cheboygan (N & A 1932); WUP, Iron; Isle Royale (Prescott 1940). 119. Staurastrum pseudotetracerum (Nordst.) West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:122. P1. 149, Fig. 11. This small species has cuneate semicells with short, strongly diverging processes. The processes are ter- minated by three spines; 2-3 concentric series of gran- ules also occur around each process. The vertical View of the semicell is triangular or quadrangular with con- cave lateral margins and with the short processes orna- mented with 2-3 concentric series of granules and ter- minated by three spines. This species has a stouter appearance than S, tetracerum. Measurements: L. ssp. 12-19u; L. csp. 19-25u; W. csp. 19-30u; I. 5-6u. 461 Distribution: NLP, Cheboygan (N & A 1932). 120. Staurastrum paradoxum Meyen West, West and Carter, 1923. Monogr. Brit. Desm. 5:101. Pl. 145, Figs. 1-5. This very variable species has obversely triangular to subcampanulate semicells. The processes are usually long and somewhat attenuated, always divergent and orna- mented by concentric series of granules (which may be developed into short spines at the base of the process), and terminated by three or four spines. The vertical view of the semicells is triangular or quadrangular with a straight or slightly concave lateral margins and with the processes ornamented with concentric rings of granules and terminated by three or four spines. According to Smith (1924), and West, West and Carter (1923), the gran- ules on the processes may be developed into Spines under certain conditions. Specimens from Chippewa County agreed well with the typical description except for the basal regions of the processes which developed into single or biSpinate projections. In accordance with the views of Smith (1924), and West, West and Carter (1923) above, they are retained here but should be compared with S, 2222? trophorum var. subgenuinum Gronbl. (Borge 1930). Measurements: L. ssp. 21-22-36u; L. csp. (30)-35-65u; W. ssp. l8—25u; W. csp. 41-(43)-88u; I. 5-(8.5)-llu. Distribution: SLP, Muskegon (Transeau 1917) and Ionia Wade (1949); NLP, Cheboygan (N & A 1932), Welch 1938a, 1938b); EUP, Chippewa. 462 121. var. parvum West West, West and Carter, 1923. Monogr. Brit. Desm. 5:106. Pl. 145, Fig. 6. This variety differs from the typical in the smaller size. Measurements: L. ssp. 9-16-(17)u; L. csp. l8-(33)-35u; w. 20-(32)-35u; I. 3.5-6-(7)u. Distribution: EUP, Chippewa; Isle Royale (Prescott 1940). 122. var. longipes Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:103. Pl. 146, Figs. 2, 3. This variety is distinguished from the typical by the small body of the semicell, and the longer and more graceful and often slightly curved processes. Measurements: L. ssp. 26-29u; L. csp. 77-84u; W. SSp. 15—l7u; W. csp. 84-139u; I. 8-9.5u. Distribution: NLP, Cheboygan (Taft 1939). 123. Staurastrum po1ymorphum Bréb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:125. Pl. 142, Fig. 24; Pl. 143, Figs. 1+3. This somewhat variable species has semicells which may be either subelliptical, subfusiform or subcuneate. The processes are fairly short and robust and are hori- zontal'or slightly convergent. In addition, they are ornamented with 3-4 concentric series of granules and terminated by 3-4 short spines. In vertical view, the .463 Semicells are 3-7 angular with the processes often of different number on the two semicells, and often alter- nating in different vertical planes. The apices are smooth in the center of the semicells. Many small Speci- mens encountered during the study are asSigned here, because of the variability of this species and because of the lack of good diagnostic features found in these specimens. Some of the specimens are somewhat larger than typical. Measurements: L. 17-21;(26)-30-(34)-36u; W- 21-(21)' 43-(44)-49u; I. (4)-5.5-(9)-10-(10.5)u. Distribution: SLP, Calhoun, Washtenaw, Ingham, Living- ston, Barry (2), also Wayne (Campbell 1886), Macomb (Pieters 1894) and Kalamazoo (N & A 1932); NLP, Roscommon, Crawford, also Cheboygan (N a A 1932 and Neel 1948); EUP, Mackinac; WUP, Gogebic (2), Houghton. 124. Staurastrum inflexum Bréb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:108. Pl. 143, Figs. 7, 8. This somewhat variable, small species, has fusiform semicells with slender, slightly attenuated and conver- gent processes ornamented with several concentric series of denticulations and terminated by 2-3 small spines. The vertical view of the semicells is triangular with the denticulate processes often slightly twisted or the semi- cells twisted at the isthmus so that the processes of the 464 two semicells alternate. The lateral margins are con- cave and the apices often have an intramarginal linear series of granules. Measurements: L. (17)-19-(19)-(2l)-26-(28)u; W. ssp. 10.5113 W. 6813- 30-(32)-(35)-(36)-(37)-40u; I- 4546-5)- (8)-8n. _ ' Distribution: SLP, Barry, Calhoun, Oakland; NLP, Che- boygan (N a A 1932); EUP, Alger, Mackinac, Schoolcraft; WUP, Marquette, Gogebic. 125. Staurastrum crenulatum (Naeg.) Delp. West, West and Carter, 1923. Monogr. Brit. Desm. 5:110. Pl. 143, Figs. 9-13. This small’somewhat variable species has broadly oval or subfusiform semicells with parallel or slightly convergent processes of variable length. The processes are undulate, denticulate and often become emarginate near the bases. The vertical view is 3-5 angular with usually two pairs of emarginate granules just within the concave lateral margin. Measurements: L. 20-28-(32)-u; W. 20-(25)-33u; I. 5-8- (10)u. Distribution: SLP, Ingham also Macomb (Pieters 1894); WUP, Houghton, Gogebic; Isle Royale (Prescott 1940). 126. var. britannicum Messiykommer P1. 29, Fig. 2. Messiylkommer, 1927. Ina‘gr. Disser.:107. P1. 5, Fig. 8; Pl. 6, Figs. 1, 2. 465 A few specimens from Barry County are assigned here questionably. Typically, this variety is 3-5 radiate with well developed processes which are ornamented with sev- eral concentric series of granules and terminated by three small spines. The apices are ornamented by a pair of emarginate verrucae placed intramarginally between the bases of the processes. Irenee-Marie (1938), illustrates a similar organism identified as S, crenulatum (Naeg.) Delp. The five-radiate Michigan specimens differ only in the presence of three intramarginal granules between the bases of each pair of processes. Measurements: 17.5-28u; W. 22.5-33-(34)u; I. 6-8u. Distribution: SLP, Barry. New record for Michigan. 127. Staurastrum marggritaceum (Ehrenb.) Menegh. West, West and Carter, 1923. Monogr. Brit. Desm. 5:131. Pl. 150, Figs. 5-9. This species has variabls Shaped semicells, the usual expression being cyanthiform or subfusiform. The angles are projected into very short, truncate processes which may be either emarginate or ornamented with small granules at the apices. Small granules are arranged in concentric series around the processes and may occur in a transverse row around the base of the semicells. The vertical view is 3-9 angled with the central portion of the apices smooth. The lateral margins are concave. Sometimes the apical granules within the lateral margins are very well developed. 466 Measurements: L 24-(27.5)-35u; W. 24-(32)-48u; I. 6—10-(10.5)u. Distribution: SLP, Berrien, Barry (2), also Ingham (N & A 1932) and Macomb (Pieters 1894); NLP, Roscommon, also Cheboygan (N & A 1932, Welch 1938a); EUP, Chippewa, Schoolcraft (3), also Schoolcraft (N a A 1932); WUP, Gogebic (3), Baraga (2); Isle Royale (Prescott (1937) ). 128. var. robustum West and.West West, West and Carter, 1923. Monogr. Brit. Desm. 5:133. Pl. 150, Fig. 13. This variety is somewhat more stout than the typical. In vertical view, there is an emarginate verruca on each side of the base of the process. Measurements: L. 25.5u; W. 27u; I. 8u. Distribution: Isle Royale (Prescott 1940). 129. Staurastrum protectum var. planctonicum G.M.Smith Pl.29, Fig. 3. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):870 P10 74, Figs. 1-4. This organism has broad,obversely triangular semi- cells with the angles continued into divergent processes of a short or medium length. Each process is tipped with two stout divergent Spines, and ornamented with concen- tric series of granules. The apices have tridenticulate verrucae. The vertical view is triangular with concave lateral margins. The central portion of the apex has a circle of about five tridenticulate verrucae. The pro- 467 cesses on specimens from Calhoun County are shorter and somewhat less divergent than those illustrated by Smith (1924a). Measurements: L. ssp. 23-31u; L. csp. 32-(34)-39u; W. ssp. 28-35u; W. csp. 40-(43)-57u; I. 6-9u. Distribution: SLP, Calhoun. Newkrecord for Michigan. 130. Staurastrum proboscideum (Bréb.) Arch. West, West and Carter, 1923. Monogr. Brit. Desm. 5:129. Pl. 143, Figs. 14-16. The semicells of this species are transversely sub- elliptic or subcuneate. The processes are short and stout, truncate, parallel or slightly convergent and terminated by a ring of small granules. In addition, there are several concentric rings of granules around each process as well as a single transverse row around the base of the semicells. The vertical view is tri- angular (sometimes quadrangular) with concave lateral margins and short, stout, truncate processes. The pro- cesses have several concentric rings of granules and the apical portion of the semicell bodykhas two lateral series of granules along each lateral margin, the inner- most often being composed of emarginate verrucae. Measurements: L. 35-(43)-45u; W. 30-43-53u; I. lO-(11.5)- l5u. . Distribution: NLP, Cheboygan (N a: A 1932): EUP, Delta. 131. var. ornatum var. 22!, P1. 29, Fig. 6. This organism.differs from the typical in the pos- 468 session of well-develOped linear series of verrucae along the lateral margin between the processes. Speci- mens from Gogebic County lacked the transverse row of granules around the base of the semicells found inwthe typical. An apparendbsomewhat reduced form was collected from Marquette County. In this latter expression, the organism has the transverse row of granules across the base of the semicell and the processes and cell are some- what shorter. Measurements: L. 29436u; W. 32-42u; I. lO.5-l2.5u. Distribution: EUP, Gogebic, Marquette. 132. Staurastrum Sebaldii Reinsch West, West and Carter, 1923. Monogr. Brit. Desm. 5:166. Pl. 148, Figs. 5, 6. The cyathiform semicells of this species have short, stout converging processes which are ornamented by con- centric series of denticulations and terminated by three or four spines. The convex apical margins possess a row of large simple or bifid-quadrifid spines. In addition, there may be a subapical row of similar structures along the lateral margin between the processes. The vertical view is triangular with straight or slightly convex lat- eral margins and short denticulate processes. A linear series of large spines is located within the lateral mar- gin, and sometimes a secondary row will be found upon the margin itself. 469 Measurements: L. 50-85u; W. 55-100u; I. 17-24u. Distribution: SLP, ‘alamazoo (N a A 1932); NLP, Cheboy- gan (N & A 1932); WUP, Iron, Menominee. 133. var. ornatum Nordst. P1. 29, Fig. 5. West, West and Carter,l923. Monogr. Brit. Desm. 5:167. P1. 148, Fig. 7. This variety has longer processes thankthe typical. There also may be a group of verrucae on the lateral margin just below the base of the processes and a trans- verse row of granules or short spines across the base of the semicells. Measurements: L. 50-(52)-(60)-81u; W. (60)-(68)-88-132u; I. 15-(17)-(18)-22u. Distribution: SLP, Oakland; NLP, Emmet. New records for Michigan. 134. Staurastrum pseudosebaldii Wille West, West and Carter, 1923. Monogr. Brit. Desm. 5:133. Pl. 146, Fig. 4. This Species has cyathiform semicells with stout, horizontal or convergent processes which are terminated by 3-4 spines. The granulation occurs in concentric series around the processes and in a single transverse row along the base of the semicells. The vertical view is triangular with concave lateral margins. The ornamentation consists of two linear series of bifid spines, one within and one upon the lateral margins. 47o Specimens from Oakland County are smaller than typical but have the characteristic bifurcate apical spines. The measurements are close to var. simplicius, West which lacks the bifurcate spines. Measurements: L. (32)-43-55u; W. (43)-60-65u; I. (9)-9-l3u. Distribution: SLP, Oakland, Barry; EUP, Alger; Isle Royale (Prescott 1940). 135. Staurastrum rugosum Irénee-Marie P1. 29, Fig. 7. Irénee-Marie, 1938. Flor. Desm. de la Reg. Mont. :311. P1. 59, Figs. 4, 5- The elliptic angular semicells have short processes which are trifid at the apices. The granulation is in concentric series around the processes. The vertical view is triangular, with slightly concave lateral mar- gins and with a central ring of 10-12 large granules which may be emarginate or Spinous. A few specimens from Oaklandcg‘oenstgmble this species and are questionably assigned here because the apical ornamentation consisted of an outer linear series of 3-4 granules, and an inner series of four granules within each lateral margin. Measurements: L. 35-36u; W. ssp. 35-40u; W. csp. 45-50u; I. 13-15u. Distribution: SLP, Oakland. New record for Michigan. 136. Staurastrum vestitum Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:158. Pl. 151, Figs. 9-11; Pl. 162, Figs. 5, 6. 471 This characteristic species has subfusiform semi- cells with long parallel or somewhat divergent processes which are ornamented with several concentric rows of denticulations and terminated by three divergent spines. The lateral margin between the processes has either a linear series of Simple spines in which the middle two are larger, or the series is reduced in number and only two granules or spines (bifurcate or simple) are present. The apices may be convex or straight with a crown of verrucae. The lateral view is triangular with concave lateral margins and denticulate processes. A linear series of verrucae which may be emarginate or Spinous is present within each lateral margin andaSecondary series (sometimes reduced to two) is present an the margin. Measurements: L. 24-(38)-(43)-43u; w. 58-(64)-(74)-(87)- 90u; I. 9-(10.5)-13-(14.5)u. Distribution: SLP, Oakland, Barry (2), Calhoun, Barry; NLP, Cheboygan (N & A 1932, Welch 1936b); EUP, Chippewa (2); WUP, Gogebic (2). 137. var. tgrtum. West Irénee-Marie, 1938. Flor. Desm. de la Reg. Mont.:326. P1. 56, Figs. 4, 5. This variety differs from the typical in possession of processes which are all curved in the same direction (in vertical view). Measurements: L. 34-35u; W. 45-(59)-65u; I. 15-l6u. Distribution: SLP, Barry; NLP, Cheboygan(N & A 1932); EUP, Alger. 472 138. var. subanatinum West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:159. P1. 153, Fig. 5. This variety has long and slightly divergent pro- cesses. The arrangement of the verrucae is similar to that of S, anatinum Cooke and Wills but the emarginate verrucae or Spines ontthe lateral margins easily dis- tinguishes it. Measurements: L. 30-(32)-42u; W. ssp. 22-(30)-30u; W. csp. 60-66-72-102u; I. lO-(lO.5)-(l3)-l3.5u. Distribution: SLP, Calhoun, Barry; NLP, Cheboygan (N & A 1932); EUP, Schoolcraft. 139. var. semivestitum. West fa. P1. 30, Fig. 5. West, West and Carter, 1923. Monogr. Brit. Desm. 5:160. Pl. 152, Figs. 7, 8. This variety is smaller than the typical and the processes in vertical view are sometimes twisted. Char- acteristically, the spines are much reduced withfightire dorsal series absent and the lateral series consisting of a single bifurcate spine on one side at the base of each process. Specimens from Chippewa County have the processes only slightly twisted and two bifurcate pro- cesses are present on each lateral margin. Measurements: L. 20-(2l.5)-28u; W. (28)-34-42.5u; I. 4-(6.5)-8u. Distribution: EUP, Chippewa. New record for Michigan. 473 I 140. Staurastrum quebecense Irgnge-Marie var. ornatum var. nov. P1. 30, Fig. 2. This organism very well might be related to many species, but is assigned here as a new variety for the reasons to be discussed below. The semicells of this variety as in the typical, are distinctly inflated at the bases, although the ornamentation in this region con- sists of three transverse rows of small granules or a single row of tridentate verrucae, rather than a single transverse row of large granules. A large sinus separ- ates the basal inflation from the upper lateral margins which are continued into slightly attenuated processes which are terminated by short spines at their apices. The processes are ornamented by large Spines along both. margins, several spines near the base of the processes on the dorsal margin being replaced by small verrucae. The lateral margin between the processes bears two small granules or spines. The vertical view of the semicell is triangular with straight lateral margins (concave if considering the processes) that are ornamented with two minute spines or granules, and with the angles continued into long, undulate, marginal processes which are term- inated by four spines at the apices. The apices possess a circle of emarginate verrucae composed of two pairs within each lateral margin. The base of the processes also has one or two pairs which are placed parallel with the process. 474 This organism should be compared with illustrations of one identified by Dick (1919) as S, gracile var. coro- nulatum Boldt. which differ greatly from the illustra- tions shown by West, West and Carter (1923), and with S, gracile var. Splendidum Messikommer (Messikommer 1928). The Michigan specimens differ from the former in type of basal ornamentation, in the presence of the secondary apical verrucae on the dorsal base of the processes and in the presence of a pair of Short Spines or granules on the lateral margins between the processes (rather than tridentate verrucae). It differs from the latter(S, ‘ra- cile var. Splendidum) in the more pronounced basal in- flation, in the basal ornamentation, in the secondary apical verrucae on the dorsal base of the processes and in the presence of a pair of short spines or granules on the lateral margins between the processes (rather than a pair of verrucae). S, pSeudosebaldii var. gostyniense Racib. has both similar basal inflation and ornamentation, but the processes are markedly convergent, the lateral margins are verrucose and the apical ornamentation is different. Measurements: L. 40-43u; W. csp. 49-55u; I. 10.5u. Distribution: EUP, Alger, Delta. 141. Staurastrum aculeatum (Ehrenb.) Menegh. West, West and Carter, 1923. Monogr. Brit. Desm. 5:161. P1. 153, Figs. 1-4. 475 The transversely subelliptical or subfusiform semis cells of this Species have the angles very slightly pro- duced (sometimes scarcely at all) into processes which are ornamented with one or two series of denticulations and terminated by 3-4 sharp spines. The apical margin possesses a series of spines of which the middle few are often emarginate. In addition, the lateral margin pos- sesses another series of Spines between the angles. The vertical view is triangular or quadrangular with straight or slightly convex lateral margins and Slightly produced processes which terminate in three or four Spines. Orna- mentation consists of a linear series of spines (the middle ones sometimes emarginate) within the margin and an additional series upon the lateral margin. Measurements: L. 33-50-(52)u; W. csp. 38-(54)-60u; I. 12-16-(19)u. Distribution: SLP, Washtenaw; NLP, Cheboygan (N a A 1932). 142. Staurastrum Cerastes Lund. West, West and Carter, 1923. Monogr. Brit. Desm. 5:141. Pl. 150, Fig. 16; Pl. 151, Fig. 1. This very characteristic species cannot be easily confused with any other Species of Staurastrum.as yet reported from.Michigan. The trapeziformerectangular semicells have a strongly convex dorsal margin and strongly convergent processes. The apex has a row of 476 strongly developed verrucae which become reduced to conical verrucae when continuing upon the processes. In addition, there is a lateral row of simple verrucae upon the lateral margin, and also a transverse row of papillae or mucros upon the base of the semicells. The vertical view is triangular or quadrangular with concave and verrucose margins, and with an additional row of verrucae upon the lateral margin. Measurements: L. 45-(54)-57u; W. 40-(66)-72u; I. 10-(13.5)-l7.5u. Distribution: SLP, Berrien; NLP, Cheboygan (N & A 1932); WUP, Gogebic. 143. Staurastrum longiradiatum West and West Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):90. P1. 74, Figs. 5-11. This species has campanulate semicells with cyathi- form bases and with long, slightly attenuated, parallel or slightly convergent processes. The processes are crenulate upon both the upper and lower margins, but more shallow in the latter, and are terminated by four short, divergent spines. The vertical view is triangular with straight or slightly concave lateral margins and with long processes with undulate or crenulate margins which terminate in four short spines. The apices have two or three verrucae within each lateral margin. Measurements: L. ssp. 41-49u; L. csp. 46-(89)-96u; W. ssp. 20-28u; W. csp. 73-(80)-108u; I. 8.5-(9)-10u, 477 Distribution: SLP, Barry; Isle Royale (Taylor 1935). 144. Staurastrum protractum. (Wolle) Johnson Johnson, 1895. Bull. Torr. Bot. Club. 22(7):295. P1. 2, Fig. 35. This species has semicells (without processes) that are nearly rectangular. The base of the semicell} is swollen and provided with two minute spines on the margin. The processes are short, ornamented by concentric series of denticulations and terminated by three spines. The vertical view is triangular with concave margins and the apices are ornamented with a circle of six bifid or tri- fid granular projections. Measurements: L. 44u; W. 50-52u. Distribution: SLP, Washtenaw (Johnson 1895). 145. Staurastrum elongatum. Barker West, West and Carter, 1923. Monogr. Brit. Desm. 5:156. Pl. 151, Figs. 2-5. This very characteristic species has cells that are about Six times longer than broad (without processes). The semicells are cyathiform with inflated bases that are ornamented with three or four transverse rows of granules. The apex which is truncate in the middle is ornamented with several emarginate verrucae. The pro- cesses which are short and usually parallel, are orna- mented by three concentric series of sharp denticulations and terminated by three small spines. The vertical view 478 is triangular with concave bi-verrucose lateral margins and short, stout processes. There are two additional verrucae within each lateral margin. Measurements: L. (58)-60-77u; W. ssp. 14-15u; W. csp. 40-(43)-48u; I. 7.5-(8.5)-9u. Distribution: NLP, Cheboygan (N & A 1932); EUP, Chippewa. 146. Staurastrum anatinum Cooke and Willis West, West and Carter, 1923. Monogr. Brit. Desm. 5:142. P1. 146, Fig. 7; Pl. 142, Fig. 1. This Species has broad cyathiform.semice11s with long, slightly attenuated, subparallel or divergent pro- cesses which are ornamented with several concentric series of denticulations and terminated by 2—3 divergent spines. The body ornamentation consists of an apical row of 6-7 emarginate verrucae and of a subapical row of similar verrucae. The vertical view is triangular with slightly concave to slightly convex lateral margins which are verrucose. The apices are smooth except for a linear series of verrucae within each lateral margin. Measurements: L. ssp. 33-46u; L. csp. 50-65u; W. ssp. 40u; W. csp. 80-ll3u; I. lO-l5.5u. Distribution: NLP, Cheboygan (N & A 1932). 147. var. longibrachiatum West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:146. P1. 147, Fig. 5. This variety lacks the subapical row of verrucae and -. W—W 479 possesses much longer processes than the typical. Measurements: L. ssp. 30-37u; L. csp. 37-80u; W. ssp. 28-37u; W. csp. 68-13lu; I. 10.5-12u. Distribution: NLP, Cheboygan (N & A 1932). 148. var. truncatum. West P1. 30, Fig. 1. West, West and Carter, 1923. Monogr. Brit. Desm. 5:145. Pl. 146, Fig. 8. The semicells of this variety are more elliptical than the typical and the processes are inserted lower on the semicells and appear to arise rather abruptly. Measurements: L. 50-(60)-68u; W. 75-(80)-lOOu; I. 15- (16)-20u. Distribution: EUP, Schoolcraft. New record for Michigan. 149.. Staurastrum floriferum West and West. P1. 31, Fig. 1. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):91. P1. 74, Figs. 12-18. This species has obversely trapeziform semicells with long, parallel or divergent processes. The pro- cesses are tipped with three sharp divergent spines and the margins of the processes are ornamented with short spines. The apices have a row of emarginate verrucae. The vertical view is triangular with slightly concave lateral margins (without processes) and with two emar- ginate verrucae within each lateral margin. Measurements: L. ssp. 22-26u; L. csp. 23-(38)-44-(52)u; w. ssp. 19-26u; w. csp. 52-(62)-(68)-(75)-86u; I. 6.5-8u. "- fi:_-—_;r_—e-—-— ’ 480 Distribution: SLP, Barry, Oakland; NLP, Presque Isle. New record for Michigan. 150. Staurastrum boreale West and West P1. 30, Fig. 3. West, West and Carter, 1923. Monogr. Brit. Desm. 5:112. Pl. 146, Fig. 5. This species has cup-shaped semicells with long, slightly divergent processes which are ornamented with several concentric series of denticulations and terminated by three Spines. The bases of the semicell have a trans- verse row of sharp granules, and the apices have a row of emarginate granules. The semicells are triangular in vertical view, with a single series of three granules and further within three emarginate’submarginal verrucae. Measurements: L. 27-31-(32)u; W. 43-46-(52)u; I. 7-8-9u. Distribution: EUP, Schoolcraft. New record for Michigan. 151. Staurastrum Manfeldtii Delp. West, West and Carter, 1923. Monogr. Brit. Desm. 5:114. Pl. 148, Fig. 2. This species has subcuneate to cyathiform semicells with long parallel processes which are ornamented with several concentric series of denticulations and terminated by three small spines. The apices have a row of emar- ginate verrucae, and the body of the semicells may be irregularly covered with denticulations or have small groups of minute granules irregularly scattered or forming a band around the base of the semicells. The vertical 481 view is triangular with a linear series of emarginate verrucae just within the straight or slightly convex lateral margins. Measurements: L. 42—57u; W. 55-lOOu; I. 9-l3u. Distribution: NLP, Cheboygan (N & A 1932). 152. Staurastrum gracile4_Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:96. Pl. 144, Figs. 3-7. The concept of this species characteristics is some- what variable. Carter (West, West and Carter 1923) who monographed the genus Staurastrum with the use of the Wests critical notes and drawings, states that the pro- cesses are either horizontal or sometimes slightly con- vergent, and that this feature distinguishes this species from S, paradoxum Meyen. However, Smith (1924), after examining the original collection of the Wests, believes that the two species cannot be separated on the basis of the length and divergence of the processes, and notes that the presence of a linear series of paired granules (apical verrucae) within the lateral margin in end view, is the only characteristic which aptly separates them. The writer follows Smith in this matter. The semicells are broadly triangular to cyathiform, with the apices possessing a row of small emarginate verrucae. The pro- cesses may be parallel or divergent, and are ornamented with concentric series of granules, and terminated by 482 three or four small spines. The vertical view is tri- angular with slightly concave lateral margins, and with linear or intramarginal pairs of granules (sometimes with additional single row of granules between the lat- eral margin and the paired granules). Measurements: L. 27-107u; W. 44-(45)-ll8u; I. 5.5-llu. Distribution: SLP, Wayne (Campbell 1886), Macomb (Pieters £1894), Washtenaw (West and West 1898), Kent (N & A 1932) and Ionia (Wade 1949); NLP, Roscommon, also Cheboygan (N a A 1932)( Welch 1936a); EUP, Alger; WUP, Gogebic. 153. var. coronulatum Boldt. P1. 30, Fig. 4. West, West and Carter, 1923. Monogr. Brit. Desm. 5:100. P1. 144, Fig. 10. This variety is often smaller than the typical, and possesses shorter processes. The apex has two emar- ginate verrucae on each Side of the process. The ver- tical view is triangular or quadrangular with two emar- ginate verrucae within each lateral margin. Measurements: L. 21-(33)-36u; W. 32.5-(42)-43u; I. 6- (9)-llu. Distribution: EUP, Chippewa. New record for Michigan. 154. var. 22222. Wille West, West and Carter, 1923. Monogr. Brit. Desm. 5:100. Pl. 144, Figs. 8, 9. This variety is separated from the typical on the basis of the smaller size. The apical view 18 3-5 angu- 483 lar. Specimens from.Emmet County appear identical with this variety except for a single transverse row of granules at the base of the semicell. Measurements: L. l4—(24)-27.5u; W. 23-(32)-36u; I. 4-(8.5)—8.7u. Distribution: NLP, Emmet, also Cheboygan (N & A 1932); Isle Royale (Prescott 1937). 155. Staurastrum gyrans Johnson P1. 31, Fig. 2. Johnson, 1894. Bull. Torr. Bot. Club. 21(7):290. Pl. 211, Fig. 4. This species has cyathiform semicells with long, undulate, convergent processes which are ornamented with a median series of Spines and terminated by three short spines. The vertical View is pentagonal with a Single straight horizontal Spine at the base of each of the processes. These spinegfglways on the same side (right in vertical view) of the processes. The apices usually have a single large verrucae or granule between the bases of the processes. Measurements: L. 20-(23)-26u; W. ssp. 12-15u; W. csp. 40-(48)-50u; I. 10.5-(10.5)-ll.5u. Distribution: SLP, Barry. New record for Michigan. 156. Staurastrum distentum Wolle var. Michiganensis var. nov. P1. 31, Figs. 3, 4. This 5-radiate organism compares favorably with S, distentum Wolle. However, the Michigan Specimens have 484 a median linear row of small denticulations on the dor- sal margins, the processes are less distended at their apices which are quadrifid, and the sinus between the bases of the processes (in vertical view) is larger and not linear. The processes in Wolle's organism have an acutely pointed basal inflation, whereas the Michigan specimens have a distinct bifid secondary process on each side of the base of the semicell. This variety should be compared with S, pinnatum var. subpinnatum West and West from which it differs in the lack of both the apical ornamentation and the transverse row of granules at the base of the semicells. It also resembles S, 237 EEEEE var. asperum (Perty) Schmidle, but this organism also has apical ornamentation and a transverse row of granules across the base of the semicells. The writer was fortunate to procure this variety in zygospore forma- tion. The zygospores are Spherical and covered by long, slender spines which are slightly bifurcated at their apices. Measurements: L.23.7u; W. csp. 38.7u; I. 8.6u; Zygospore: ssp. 23.6u; cep. 43u. Distribution: SLP, Barry. 157. Staurastrum incisum Wolle Wolle, 1892. Desm. of U. S.:146. P1. 52, Figs. 12-14 This species (in vertical view) has 5-6—angled semi- cells with processes (which are toothed on the margins) 485 that are separated at their broad bases by an acute-angled or linear incision. Measurements: Diameter 36-40u. Distribution: Washtenaw (Johnson, 1894, West and West, 1898) and Macomb (Pieters, 1894). 158. Staurastrum pentacerum (Wolle) Smith Smith, 1924. Bull. Wise. Geo. and Nat. Hist. Surv. 57(2):112. P1. 80, Figs. 15-18. This very characteristic species has trapeziform- quadrate semicells with subparallel, slightly attenuated processes which are crenulate upon the upper margin and whichageerminated by three short spines. The apex bears a row of subapical verrucae. The vertical view is pen- tagonal (rarely hexagonal) with the processes of one semicell alternating with those of the other semicell, and with a large verrucae between the bases of each pair of processes (sometimes with a single smaller ver- rucae on each side of the major verrucae). 'Measurements: L. 36-fi5u; W. ssp. 18-20u; W. csp. 82-105u; I. lO-l3u. Distribution: SLP, Calhoun; NLP, Cheboygan (Taft 1939); WUP, Gogebic (2); Isle Royale (Prescott 1940). 159. Staurastrum rotula Nordst. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):116. P1. 81, Figs. 5.8. This species has subhexagonal semicells with long 486 processes arising about midway between the apex and the isthmus. The processes are ornamented by three or four concentric series of granules, and terminated by three short apines. The vertical view is 8- or 9-radiate with a single large granule or emarginate verruca at the base of each process. Measurements: L. 40-(fl6.5)-48u; W. ssp. 22-30u; W. csp. 58-70-105u; I. 10.5-l7u. Distribution: SLP, Barry; NLP, Cheboygan (Taft 1939); EUP, Schoolcraft; Isle Royale (Prescott l9#0). 160. Staurastrum ankyroides var. pentacladum G. M. Smith P1. 32, Fig. 1. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):11h. P1. 81, Figs. 1, 2. This species has cylindrical semicells in which the upper portion is projected into long convergent processes which are crenulate upon the margins, verrucose in the middle (especially near the base) and terminated by sev- eral small spines. The vertical view is five-angled with a semicircular verruca between the bases of the pro- cesses. The processes have lateral bifid verrucae near the bases and simple spines near the trispinate apices. Measurements: L. 60-(60)-68u; W. ssp. 22-28u; W. csp. 96-(107)-150u; I. (l3.5)-14u. Distribution: SLP, Barry. New record for Michigan. 161. 162. 487 Staurastrum Arachne Ralfs. West, West and carter, 1923. Monogr. Brit. Desm. 5:151. Pl. 150, Fig. 1. This Species has broadly campanulate semicells with long convergent processes which are ornamented with con— concentric rings of granules and terminated by three small spines. The vertical view is five or six radiate with a few scattered granules or only a pair, between the bases of the processes. Measurements: L. (24)-26-42u; W. ssp. 14—18u; W. CSp. 40-(43.6)-65u; I. 7.5-(ll)-l6u. Distribution: SLP, Barry (2), Calhoun, Berrien, Living- ston; NLP, Crawford, also Cheboygan (N & A 1932); WUP, Gogebic; Isle Royale (Prescott 1937, 1940, var.). Staurastrum Qphiura Lund. West, West and Carter, 1923. Monogr. Brit. Desm. 5:158. Pl. 153, Figs. 1, 2. This large species cannot be confused with any other species of this genus reported from.Michigan. The cy- athiform semicells have long, convergent processes, a transverse row of stout, conical verrucae at the base of the semicell, and a row of apical verrucae. The semicells in vertical view are usually 7-rayed (rarely 8- or 6-) and possess two emarginate verrucae withinhthe lateral margin between the processes in addition to a circle of bifid or conical verrucae. 488 Measurements: L. 47-(68)-91u; W. ssp. 34-46u; W. csp. 96-(125)-l69u; I. 10.5-26u. Distribution: SLP, Barry, Calhoun, Livingston; NLP, Cheboygan (Taft 1939), also Otsego (Taft 1939); EUP, Schoolcraft. 163. var. cambricum (Lund.) West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:154. P1. 152, Figs. 3, 4. This variety has relatively short processes and more convex apices. Measurements: L. 75-80u; W. csp. 98-110u; I. 16-18.5u. Distribution: Isle Royale (Prescott 1937). 164. Staurastrum arctiscon (Ehrenb.) Lund. West, West and Carter, 1923. Monogr. Brit. Desm. 5:193. P1. 157, Fig. 5. This large species with an accessory whorl of pro- cesses has subspherical Semicells. In vertical view, the semicells are circular and possess nine straight marginal processes and six intramarginal processes. The only other species (reported as yet from Michigan) which is circular in transverse view and which has accessory processes is §3 leptacanthum Nordst. This latter species possesses only four intramarginal accessory processes. Measurements: L. SSp. 51-96u; L. csp. 90-(107)-l55u; w. ssp. 40-68u; w. csp. 90-(107)-l60u; I. 21-(30)-33u. Distribution: SLP, Calhoun, also Muskegon (Transeau 1917) 489 and Macomb (Pieters 1894); NLP, Cheboygan (Welch_1938b); Isle Royale (Prescott 1940). ' 165. var. glabrum West and West Smith, 1924. Bull, Wisc. Geo. and Nat. Hist. Surv. 57(2):125. P1. 83, Fig. 15; P1. 84, Figs. 3-5. This variety is separated from the typical by the lack of granules on the processes. Intermediates between this variety and the typical have been reported by Smith (1924) and Iréhee-Marie (1938). Measurements: L. ssp. 60-65u; L. csp. 105-127u; W. ssp. 40-50u; W. CSp. lOl-llSu; I. 21-26u. Distribution: SLP, Oakland; NLP, Presque Isle; Isle Royale (Taylor 1935). 166. Staurastrum leptacanthum, Nordst. Smith, 1924. Bull. Wise. Geo. and Nat. Hist. Surv. 57(2):123. P1. 83, Figs. 12-14. In vertical view, this species is circular and pos- sesses six marginal processes and four intramarginal processes. In front view, the semicells axesubcircular to subhexagonal with a lower whorl of six processes arising midway between the isthmus and the apex, and an upper whorl of four processes arising at the apex. The processes are without ornamentation and bifurcate at the apices. Measurements: L. SSp. 24-48u; L. csp. 44-(68)-110u; w. ssp. 20-28u; w. csp. (52)-54-ll4u; I. ll-(13)-l4u. 490 Distribution: SLP, Livingston (N & A 1932); NLP, Che- boygan (Welch 1938b); EUP, Schoolcraft. 167. Staurastrum Senarium_(Ehrenb.) Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:176. Pl. 166, Fig. 3. This species has elliptic to subfusiform semicells with nine lower whorl processes and six upper whorl pro- cesses. The smooth processes are bifid at their apices. In vertical view, the semicells are triangular with lower whorl processes appearing at each angle. There is also an additional lower whorl process on each side of the angle. The six intramarginal upper whorl processes are arranged singly on each side of the angle. Nichols and Ackley (1932) report S, Hantzchii Reinsch from.Che- town‘s boygan. The writer believes, after an examination of the original description and original figures, that this species cannot be separated from S, senarium. A specimen illustrated by Irenee-Marie (1938), and iden- tified as S, tohopekaligense var. nonanum Turner, agrees well with the Michigan specimens, but Smith (1924) after examining collections from.England, the Eist Indies and Africa, states that the var. nonanum is synonomomwith var. trifurcatum West and West. Measurements: L. csp. 42-46-48u; W. csp. (38)-46-58u; Distribution: NLP, Cheboygan (N & A 1932, S, Hantzschii Reinsch); EUP, Schoolcraft. 491 168. Staurastrum ggmelliparum Nordst. P1. 33, Fig. 3. West, West and Carter, 1923. Monogr. Brit. Desm. 5:177. Pl. 156, Fig. 5. This species has subelliptical semicells with two short processes at each basal and apical angle. The pro- cesses are bifid, the short Spines being in the same vertical plane. In vertical view, the semicells are tri- angular with each angle being truncate and bearing four processes, the lower pair of processes being visible under the upper pair. Measurements: L. ssp. 17-25u; L. csp. 26—30-(33)u; W. esp. 20-26-(27)u; I. (5)-7.7-lOu. Distribution: SLP, Oakland, Barry. New records for Michigan. 169. Staurastrum furcatum (Ehrenb.) Breb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:175. Pl. 155, Figs. l-4. This species is characterized by transversely el- liptical-hexagonal semicells with three lower processes arising midway between the isthmus and the apex and six upper processes which are subapically inserted. The ver- tical view is triangular, with straight lateral margins and very short processes that merge gradually with the body of the semicells. Two intramarginal processes, one near each angle of the cell, arise from each side of the semicell. S, tohopekaligense Wolle has the same number 492 and arrangement of processes but the semicells are broadly oval to subglobose, the processes are much longer and the size of the semicells is much larger. Measurements: L. ssp. 20-(25)-30u; L. csp. 25-(39)-47u; W. ssp. l4-(21.5)-22u; W. CSp. 20-(32)-40u; I. 6-(lO.5)- 11.5u. Distribution: NLP, Cheboygan (N a A 1932); EUP, Chip- pewa (2), also Chippewa (N & A 1932); WUP, Gogebic. 170. var. Taylorii var. nov. P1. 34, Fig. l. This variety is distinguished from the typical by the presence of very short lateral processes which are terminated by a very stout (bifurcate near tip) Spine. Another distinctive characteristic is the insertion of two stout simple spines on the lateral margin between the processes, each Spine being in the same vertical plane as the apical process. This organism is closely related to an un-named variety reported by Taylor (1935) in which some of the lateral processes are hollow through- out, and others are similar to the Michigan specimens wherein the process has become solidified into a stout spine. Taylor's variety also has a Single spine on the periphery of the lateral margin, whereas the Michigan specimens have two on the lateral margin as described above. This variety should be compared with S, forficu- latum subheteropol fa. implex Gronblad (1920) and S, forficulatum var. subheterophorum.Gronblad (1921) from 493 which it differs in the lack of body ornamentation ex- cept the spines, and the possession of distinct apical processes rather than spines. Measurements: L. ssp. 33u; L. cop. 47u; W. ssp. 34u; W. csp. 57u; I. 8u. Distribution: EUP, Chippewa. 171. fa. spinosa Gronblad P1. 34, Fig. 2. Gronblad, 1920. Acta. Soc. pro. Faun et Flor. Fenn. 47(1): P1. 1, Figs. 31, 32, 37. This form has very Short processes which are bifur- cate at their apices. Specimens from Gogebic and Hough- ton Counties resembe this form and also S, furcatum var. aculeatum Schmidle (1895).: The general shape of the cells of both organisms are the same, but the bifurcate nature of the short processes necessitates placing them here. The processes, although bifid, were acutely pointed in some specimens, thus resembling the variety aculeatum. Irenee4Marie (1938), illustrates an organism identified as S, aciculiferum which is very similar to the Michigan specimens but which has few granules at the lateral angles. Measurements: L. ssp. 21.5u; L. csp. 25-27u; W. ssp. 21.5u; W. csp. 25-27u; I. 6.5-10.5u. Distribution: WUP, Gogebic, Houghton. New records for Michigan. 172. var. pisciforme Turner P1. 31, Fig. 5. Irenee-Marie, 1938. Flor. Desm. de la Reg. Mont. 329. P1. 55, Figs. 9, 10. 2:91: This variety has granular ornamentation on the periphery of the lateral margins of the angles. The sinus is also less open than in the typical. Measurements: L. sap. 24-27-32u; L. csp. 32-(38)-40u; w. ssp. 24-(27)-36u; w. csp. 34-(42)-48u; I. 8-9-10.5u. Distribution: EUP, Alger. New record for Michigan. 173. Staurastrum arcuatum Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:180. Pl. 155, Fig. 8. This species has fusiform semicells in which the ventral margins, which are concave, and the dorsal mar- gins, which are almost straight, are projected into short processes which terminate in two stout diverging spines. Granules are arranged in concentric series around the processes. The vertical view is triangular with concave lateral margins and sharp angles. A pair of bifid intramarginal projections are placed at each angle, one on each side of the terminal spines. Measurements: L. ssp. 20-24u; L. csp. 32-36u; W. ssp. 26-28u; W. cap. 32-49u; I. 6.5-l2u. Distribution: Isle Royale (Prescott 1937). 174. var. pseudopisciforme fa. Lgéhgg-ugzig nob. P1. 33, Fig.2. Staurastrum pseudopisciforme Irenee-Marie non Eichl.&Racib. 1938 Flor. Desm. de la Reg. Mont.:330. P1. 55, Fig. 11. Staurastrum pgeudopisciforme.lich1. and Racib. has been assigned as a variety of S, arcuatum.Nordst. Thus 495 Iréhee-Marie's (1938) report of an organism identified as S, pseudopisciforme must be considered as a variety of S, arcuatum. However, an examination of the original illustration of Eichl. and Racib. (1893) reveals an en- tirely different plant than the one shown by Irenee- Marie. The original figures have long, narrow, divergent lower whorl processes which are terminated by two stout, divergent spines. The bases of the processes have a few granules. In the upper whorl, the processes are bi- spinate. Specimens from Schoolcraft County are very Sim- ilar to those illustrated by Irenee-Marie (1938). The processes are very slightly projected, only very slightly divergent and ornamented with three concentric series of granules. The apical whorl processes are 3-6 spinate with the spines being small. The writer believes that these two organisms are sufficiently the same and that they Should be united under a new form name. Measurements: L. ssp. 27-30u; L. csp. 34-(36)-42u; w. ssp. 25-30u; w. 34-40-(42)u; I. 8-(1o.5)-117. Distribution: EUP, Schoolcraft. 175. Staurastrum forficulatum Lund. West, West and Carter, 1923. Monogr. Brit. Desm, 5:187. Pl. 154, Figs. l4-l6. This species has subtrapeziform to subelliptical semicells with two emarginate Spines or short bifid pro- cesses on the apices. The lateral margins each have a 496 short, stout process terminating in two sharply diver- gent spines. In vertical view, the semicells are tri- angular or quadrangular with short processes terminat- ing in short spines and concave lateral margins. Each side has two spines or processes upon each margin and two spines or porcesses within each margin. Measurements: L. ssp. 40-45u; L. csp. 48-64u; W. ssp. 37-60u; W. csp. 54-95u; I. 9-l6u. Distribution: NLP, Cheboygan (N & A 1932). 176. var. cornutiforme var. nov. P1. 33, Fig. 1. This organism, while closely related to S, forficu- l§£2m_Lund., and varieties of this species, possesses a pattern of apical verrucae which is suggestive of S, 225- 22332 Archer. In front view, the elliptical semicells are similar to the former. Also confirming the close re- lationship of this organism to S, forficulatum (as seen in vertical view) is the insertion on each lateral mar- gin of a single spine or projection on each side of the angle. Two bifurcate processes are also placed within each lateral margin. The intramarginal linear rows of emarginate granules or verrucae within the bifurcate projections, however, is suggestive of S, cornutum, es- pecially those specimens illustrated by Gronblad (1920). Measurements: L. 48u; W. ssp. 44u; W. csp. 67u. Distribution: NLP, Crawford. 177. Staurastrum tohopekaligense Wolle West, West and Carter, 1923. Monogr. Brit. Desm. 5:178. Pl. 155, Fig. 12. 497 This Species had broadly oval to subglose semicells with three lower parallel processes and six upper divergent processes. In vertical view, the triangular semicell has each angle projected into long processes which have two or three hollow spines at the apices. Two intra- marginal accessory processes, one near each angle, arise from each side of the semicell. The different semicell shape and the longer processes separate this species from S, furcatum (Ehrenb.) Breb. Measurements: L. ssp. 29-5lu; L. csp. 48-91u; W. ssp. 23-28-40u; W. csp. 50-96u; I. l3-l9u. Distribution: Isle Royale (Prescott 1940). 178. var. brevispinum G. M. Smith P1. 33, Fig. 4. Smith, 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):121. P1. 82, Figs. 8-11. This variety is distinguished from the typical by the shorter processes and the much Shorter spines ter- minating the processes. Measurements: L. ssp. 26-(30)-32u; L. csp. (43)-46-53u; W. ssp, (21.8)-24-25u; W. csp. (34)-37-50u; I. ll-(13)-l5u. Distribution: NLP, Roscommon, Emmet; EUP, Schoolcraft. New records for Michigan. 179. Staurastrum furcigerum Breb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:189. P1. 156, Figs. 7, 8, 11. This species has elliptic-hexagonal semicells with 498 two whorls of processes. The three processes in each whorl all have concentric series of granules. The ver- tical View is triangular with short truncate processes which are ornamented with several concentric series of granules. An additional intramarginal process is present at each angle. 4 Measurements: L. ssp. 30-48u; L. csp. 50-(55)-72u; W. ssp. 22-40u; W. csp. 45-(50)-80u; I. 12.5-(15)-19u. Distribution: SLP, Barry, Washtenaw, Jackson also Macomb (Pieters 1894); NLP, Cheboygan (N a A 1932); EUP, Alger, Schoolcraft, also Delta, Manistique (N a A 1932); WUP, Iron; Isle Royale (Prescott 1937, 1940). 180. var. armigera (Breb.) Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:191. P1. 146, Fig. 10. This form is separated from the typical by the longer processes whicha'c‘renulate-undulate rather than denticu- late, and by the six processes in the upper whorl. Measurements: L. ssp. 31-45u; L. csp. 49-80u; W. 889- 25-35u; W. csp. 52-70u; I. lO—l5u. Distribution: NLP, Cheboygan (N & A 1932); WUP, Mar- quette. 181. fa. eustephana (Ehr.) Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:190. Pl. 157, Fig. 1. This form has the six upper whorl processes as in 499 var. armigera, but they are ornamented with concentric series of granules as in the typical. Measurements: L. ssp. 32—40u; L. csp. 40-(42)-58u; W. ssp. 28-30u; W. csp. 46-(56)-56u; I. l2-16u. Distribution: SLP, Wayne (Campbell 1886); NLP, Crawford, also Cheboygan (N & A 1932); EUP, Schoolcraft, Delta, Alger; WUP, Menominee. 182. Staurastrum monticulosum Breb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:183. Pl. 154, Fig. 8. This species has subtrapeziform semicells with two whorls of processes. The six short conical processes in the upper whorl are not ornamented with concentric rings of granules and possess only single spines. The pro- cesses of the lower whorl are short and stout, ornamented with concentric rows of granules, and bear two divergent spines. The vertical view is triangular with straight or very slightly convex lateral margins. Two short in- tramarginal projections with simple spines occur at each angle which is bispinate (one Spine above the other). Measurements: L. csp. 40-57u; W. csp. 35-42u; I. 13-l9u. Distribution: WUP, Marquette. (Pres. and Mag. 1935). 183. var. bifarium Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:184. Pl. 154, Fig. 9. This variety is separated from the typical by emar- 500 ginate apical processes and by the possession of bifid projections along the middle of the lateral margins of the semicells. Specimens from Barry County lack this latter characteristic but have bifid apical processes. Measurements: L. sSp. 29-37u; L. CSp. (49)u; W. ssp. 30-34u; W. csp. (45)u; I. 10-13—(15)u. Distribution: SLP, Barry; NLP, Cheboygan (N & A 1932). 184. Staurastrum bicoronatum Johnson P1. 34. Fig. 3. Johnson, 1894. Bull. Torr. Bot. Club. 21(7):290. P1. 211, Fig. 9. This species has subhexagonal semicells. The angles are prolonged into processes, each of which have tri- serrate margins and a trifid apex. The vertical view is triangular with each process possessing a pair of short, bifid secondary processes at the base. A pair of bifid verrucae are located inside each lateral margin. Speci- mens from Oakland and Calhoun Counties are slightly larger than typical measurements. Measurements: L. 14-16-(18)u; W. 22-25-(32u; I. 6-(10)u. Distribution: SLP, Calhoun, Oakland. New records for Michigan. 185. Staurastrum erasum fa. espinulosa Lund. West and West, 1898. Jour. Linn. Soc. 33:312. Lundell, 1871 Nov. Act. Soc. Scient. Upsal. Ser. 3, 8(2):62. This writer has been unable to obtain the original 501 description of this organism because the journal is un- available. Nor are there any references (known to the writer) made to this form in any publication, except by West and West (1898) who merely report its occurrence in Washtenaw County. 22.‘ ONYCHONEMA Wallich 1860 Cells usually small and somewhat wider than long, united in filaments by two capitate asymmetrically disposed apical processes on each semicell overlapping the adjacent semicell, and often enclosediin a mucilaginous covering. Cells com- pressed, with a deep median constriction and narrow sinus. Semicells elliptic in front view, sometimes with a single, long, convergent spine on each lateral angle. Cell wall finely punctate, smooth or with transverse rows of granules or pores. Cells in vertical view fusiform-elliptic with apical processes alternately inserted and the poles rounded or with a Single Spine. Each semicell with a single axial, plate-like chloro- plast with a single pyrenoid. Zygospores spherical with Simple short spines. Key to Species of Onychonema 1. Lateral angles of the semicell with a sharp projection or spine . . Q, laeve 1. Lateral angles of the semicell broadly rounded and without spines 9, filiforme l. Onychonema laeve Nordst. West and West and Carter, 1923. Monogr. Brit. Desm. 5:218. Pl. 160, Figs. 15, 16. 502 This species is characterized by the convergence of the lateral margins into a long horizontally pro- jecting spine. Measurements: L. l6-(l7)-l7u; W. ssp. (20)-20.5-(24)- (25u; W. csp. (24)-25-(29)-46; I. 3.5-6. Distribution: SLP, Calhoun, Oakland, Jackson; NLP, Cheboygan (N & A 1932). 2. var. micracanthum Nordst. Iréhee-Marie, 1938. Flor. Desm. de la Reg. Mont.:345. P10 61, Figs. 4-6. This variety has the lateral margins of the semi- cells converging to a sharp point or a very Short pro- jection. The writer has observed filaments in which some cells had very reduced Spines and other cells had much longer spines, thus indicating intermediate forms between the typical and this variety. Measurements: L. 15-(15.2)-16u; W. SSp. l6-19-21u; W. csp. 20-(23.5)-26u; I. 3.5-(4)-4u. Distribution: SLP, Barry, also Macomb (Johnson 1894 and Pieters 1894); NLP, Cheboygan (N & A 1932). 3. var. latum. West and West P1. 35. Fig. 4. Smith, 1924. Bull. Wids. Geo. and Nat. Hist. 57(2):136. P1. 86, Fig. 16. —This variety has a truncate elevation at the mid- region of the apical margin. Measurements: W. sp. (13)-15.5-20u; W. cp. 20-29u; W. ssp. l5-(l7)-28.5u; W. csp. (22)-23-36.5u; I. 3.8-6u. 503 Distribution: SLP, Calhoun; WUP, Gogebic, Houghton. New record for Michigan. 4. Onychonema filiforme (Ehrenb.) Roy and Biss. West, West and Carter, 1923. Monogr. Brit. Desm. 5:216. Pl. 160, Figs. 13-14. This Species has semicells with rounded lateral mar- gins without spines. Measurements: L. sp. 8.5-(10.9)-13.5u; L. cp. 92-(15)- 18u; W. 8.5-(13)-17u; I. 3.5-(5)-5.6u. Distribution: SLP, Barry, Calhoun, Livingston, Oakland, also Kalamazoo (N & A 1932); NLP, Cheboygan (N & A 1932); EUP, Alger, Schoolcraft; WUP, Iron, Marquette, Menominee, Gogebic. 23. SPHAEROZOSMA Corda. 1834 Cells generally small, often slightly wider than long, compressed, moderately constricted, with a linear, narrow or open sinus, united into filaments by apical processes or granules that are inserted on opposite sides of the semicells. lls in front view elliptic to oblong with lateral mar- Semice gins granulate or smooth. Semicells in transverse view el- liptic. Cell wall smooth, punctate or granulate. Chloroplast axial, one with a Single pyrenoid in each cell. Zygospore variable, spherical to subrectangular; walls smooth or with simple spines. Key to Species of Sphaerozosma 1. Cells joined together with inter- locking elongate apical processes. 2 504 Cells joined together with inter- locking granules . . . . . . . . . 3 2. Cell wall smooth or punctate . (3) S, vertebratum 2. Cell wall with two transverse rows of granules . . . . . . (l) S, Aubertianum var. Archeri Cells with smooth walls . . . . . . 4 Cells with some granules on wall . . (8) S, granulatum 4. Lateral margins of cells smooth . . . . . . . ... . . (2) S, exigdm 4. Lateral margins of cells gran- ular . . . . . . . . . . . . (6) S, excavatum Sphaerozosma Aubertianum var. Archeri (Gutw.) West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:208. P1. 159, Figs. 14-17. The much wider than long, transversely elliptical semicells with the two transverse rows of granules on the cell wall and the long interlocking apical processes clearly distinguish this organism. Measurements: L. sp. l2-20u; L. cp. 22-27u; W. 19-35u; Io 505-1211. Distribution: Isle Royale (Taylor 1935). Sphaerozosma exiguum Turner P1. 35, Fig. 3. Smith 1924. Bull. Wisc. Geo. and Nat. Hist. Surv. 57(2):138. P1. 86, Fig. 21. This species has transversely elliptic semicells, and a broad, fairly deep sinus. Granules are not present on the cell wall and upon the lateral margins. 505 Measurements: L. (10.5)-14u; W. (10.5)-l2.5u; I. 6.5u. Distribution: WUP, Gogebic. New record for Michigan. 3. Sphaerozosma vertebratum (Breb.) Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:209. P1. 159, Figs. 9, 10. This species has long interlocking apical processes, transversely, narrowly oblong or reniform semicells and a smooth cell wall. Measurements: L. 19u; W. 21-24u; I. 9-10u. Distribution: NLP, Cheboygan (N a A 1932). 4. fa.mi_r_i_g.r_ West West, West and Carter, 1923. Monogr. Brit. Desm. 5:210. Pl. 159, Fig. 12. This variety has slightly more depressed cells, a relatively wider isthmus and a smaller size than the typical. Measurements: L. 8-10u: W. l2-14u; I. 7.5-8u. DiStribution: NLP, Chebpygan (N & A 1932). 5. var. punctulatgm_ West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:210. Pl. 160, Fig. 12. This variety differs from the typical in the pos- session of punctate cell walls and more angular cells. Measurements: L. l4-16u; W. 17.5-20u; I. 8-9.5u. Distribution: NLP, Cheboygan (N & A 1932). 6. Sphaerozosma_g§cavatum Ralfs. West, West and Carter, 1923. Monogr. Brit. Desm. 5:211. P1. 160, Figs. 1—3. 506 This species has oblong elliptic semicells. The constriction is large’resulting in a large semicircular sinus. The cell wall is usually smooth although the lateral margins possess two to three granules. Occasion- ally there may be as few granules within the lateral margins. Measurements: L. 7.5-14u; W. 7—12.5u; I. 3.5-7.5u. Distribution: SLP, Oakland, also Muskegon (Transeau 1917); NLP, Emmet, also Cheboygan (N & A 1932). 7. var. subquadratum West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:212. P1. 160, Figs. 4, 5. This variety differs from the typical in having' relatively wider cells with a narrow and apically obtuse Sinus and oblong semicells. Measurements: 7.8-10u; W. 9—10u; I. 2.5-4u. Distribution: NLP, Cheboygan (Taft 1939). 8. Sphaerozosma granulatum Roy and Biss. West, West and Carter, 1923. Monogr. Brit. Desm. 5:213. Pl. 160, Figs. 6, 7. This species has elliptical semicells with rounded lateral angles, a semicircular sinus and three to five granules on the lateral margin. The cell wall also has at least a single granule within the margin. Measurements: L. 8-10-(10.5)u; W. 8-(8.5)-10u; I. 3.4-{ (4.2)-5u. 507 Distribution: SLP, Calhoun, Barry; NLP, Crawford, also Cheboygan (N & A 1932); EUP, Chippewa, Alger, School- craft; WUP, Gogebic. 24. SPONDYLOSIUM Breb. 1844 Cells, of variable size, often small, of a variable length-width ratio, deeply constricted, united end to end into filaments which may be twisted and enclosed in a mucil- aginous sheet. Semicells transversely elliptic, or oblong, or pyramidate with the poles truncately flattened, the apical margin sometimes concave, or in some,with the poles elevated and the apical margin convex, never with apical processes. Cell wall rarely with granules in a definite pattern, usually punctate or smooth. Chloroplasts axial, usually with a single pyrenoid. Zygospores spherical, with simple spines or smooth. Key to Species of Spondylosium l. Semicells transversely elliptical or subelliptical (may have slight truncate apices) . . . . . . . . . 2 1. Semicells truncate pyramidate . . . (l) Sp, pulchellum 2. Lateral margins of semicells with three small granules . . (2) Sp, papillosum 2. Lateral margins otherwise . . . 3 3. Cells large, more than 40u long . . (3) Sp, pulchrum 3. Cells smaller, less than 40u long . 4 4. Cells 5-8u long, 4-8u wide . . (4) Sp, pygmaeum 4. Cells larger, more than 8u long 5 and 8u wide . . . . . . . . . 508 5. Semicells transversely elliptical, length of cell 19.6-24u . . . . . (6) Sp, ellipticum 5. Semicells transversely oblong, length of cell 9.5-19.5u . . . . . . . . (7) Sp, planum l. Spondylosium pulchellum Arch. West, West and Carter, 1923. Monogr. Brit. Desm. 5:227. P1. 161, Figs. 1-3. The truncate-pyramidate semicells easily distin- guish this Species. Measurements: L. l2-(l3)-15u; W. (9.6)-10-llu; A. 5n; I. ”-5.611. Distribution: SLP, Barry, also Muskegon (Transeau 1917); NLP, Cheboygan (N & A 1932); EUP, Mackinac (Transeau 1917); WUP, Gogebic. 2. Spondylosium pplchrum (Bail.) Arch. Smith, 1924. Bull. Wis. Geo. and Nat. Hist. Surv. 57(2):140. P1. 87, Figs. 3, 4. The transversely oval (much elongated) semicells, the cells much wider than long, and the large size easily separate this species from all others in the genus. The re elevated and decidedly truncate. apices a Measurement: L. 40-54u; W. 70-85u; I. l8-22u. Distribution: SLP, Muskegon (Transeau 1917); NLP, Che- boygan (Welch 1936b); EUP, Mackinac (Transeau 1917). 3. Spondylosium papillospm_ West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:223. P1. 161, Figs. 6, 7. 509 This small species has the lateral margins pro- vided with three minute granules. Measurements: L. 8-9.5u; W. 8.5-9.5u; I. 4.5-5u; Distribution: NLP, Cheboygan (N a A 193a); EUP, Chippewa (Transeau 1917). 4. Spondylosium pygmaeum (Cboke) West West, West and Carter, 1923. Monogr. Brit. Desm. 5:220. P1. 160, Figs. 18, 19. This minute species is about as wide as long, and has transversely elliptic semicells which are united together by a relatively small portion of the apical surfaces. Measurements: L. 5-8u; W. 5-8u; I. 2.5-3.2u. Distribution: NLP, Cheboygan (N & A 1932). 5. var. monile (Turn.) West and West West and West and Carter, 1923. Monogr. Brit. Desm. 5:221. Pl. 160, Figs. 20, 21. This variety has cells that are relatively longer than the typical. The semicells are broadly oval. Measurements: L. 7u; W. 4u. Distribution: NLP, Cheboygan (N & A 1932). 6. Spondylosium ellipticum_ West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:222. Pl. 161, Fig. 15. This species has elliptical semicells with convex apices. It resembles S, planum but the shape of the semi-. 510 cells and the greater length of the cells easily dis- tinguishes it from this Species, which has transversely oblong semicells. Measurements: L. 1916-24u; W. 20-22u; I. 6.7-7u. Distribution: SLP, Ingham (N a A 1932). 7. Spondylosium planum (Wolle) West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:222. P1. 160, Figs. 23-25. This species has transversely oblong semicells with the lateral angles broadly rounded. The constriction is deep with the sinus open but obtuse at the apex. Measurements: L. (9)-9.5-(13)-19.5u; W. 9.5-(10)-(14)- Distribution: SLP, Barry (2), Calhoun, Livingston; WUP, Ontanagon (N & A 1932). 25 HYALOTHECA Ehrenb. 1841 5. Cells cylindrical or discoid, sometimes longer than wide, often wider than long; united in untwisted filaments, often covered by a mucilaginous sheath; median constriction either a slight indentation or notch or a broad shallow depression of the lateral margins; apices flattened and without projections, angles usually rounded. Cell wall smooth, or punctate, espec- ially near apices, sometimes with two transverse rows of small granules near poles. Chloroplast axial with several radiating lobes, each chloroplast with a central pyrenoid. Zygospores smooth and spherical. W L0 0 o 511 Key to Species of Hyalotheca Cells with two parallel transverse rows of granules just below apices . . . . . . . . . . . . . . (l) S, mucosa Cells without two parallel transverse rows of granules below apices . . 2 2. Cells about as wide as long (never over 1 1/4 times longer than wide) or wider than long . . . . . . . . . . (3) S, dissiliens 2. Cells more than 1 1/4 times longer than wide . . . . . . 3 Length of cells less than l8u . . . (7) S, undulata Length of cells more than 25u . . . (6) S, neglecta Hyalotheca mucosa (Mert.) Ehrenb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:235. Pl. 162, Figs. 1-4. The two transverse parallel rows of granules just below the apices clearly differentiate this Species. Measurements: L. l4-26u; W. l6-22u. Distribution: SLP, Barry; NLP, Cheboygan (N a: A 1932, Welch 1938b); EUP, Delta, Alger, Schoolcraft; WUP, Mar- quette, Gogebic; Isle Royale (Taylor 1935, Prescott 1937, 1940). var. _m__ip_o_r_ Roy and Biss. West, West and Carter, 1923. Monogr. Brit. Desm. 5:232. Pl. 162, Fig. 5. This variety is distinguished from the typical by its smaller size. 3. 4. 512 Measurements: L. 12.5-14.5u; W. 9-l2u. Distribution: NLP, Cheboygan (N & A 1932). Hyalotheca dissiliens (Smith) Breb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:229. P1. 161. Figs. 16-27. This somewhat variable species has the following characteristics: the cells are about 1 1/4 - 2 times wider than long; the cylindrical discoid cells have the constriction reduced to a Slight concavity or indenta- tion, and the apices are flattened. Cell wall smooth, or punctate, especially near the apices. Measurements: L. 10-(17)-33; W.20-39u. Distribution: Very common and widespread in the writer's collection. SLP, Barry (3), Calhoun, Washtenaw (2), Jackson; also Barry, Calhoun, Ingham, Kalamazoo (N & A 1932), Allegan, Muskegon (Transeau 1917) and Macomb (Pieters 1894); NLP, Crawford, Emmet, also Cheboygan (N & A 1932, WeICh 1936a, 1936b); EUP, Delta, Alger, Schoolcraft (4), Mackinac, also Chippewa, Luce, Mackinac (N & A 1932) and Schoolcraft (Transeau 1917); WUP, Gog- ebic (3), Marquette (2), Houghton, Baraga, also Houghton, Onatanagon (N & A 1932); Isle Royale (Prescott 1937, 1940). var. plgpp' Wolle I West, West and Carter, 1923. Monogr. Brit. Desm. 5:234. Pl. 162, Figs. 16-18. This variety is often conspicuously constricted at 513 the joints. The lateral margins are distinctly convex with a distinct median indentation or notch. The cells are also usually much longer than wide. The writer's specimens from Roscommon agree favorably with the form illustrated by Taylor (1935) from New Foundland. Measurements: L. (11)-12-22u; w. 20-(28)-32u. Distribution: SLP, Ingham, Saginaw (N & A 1932); NLP, Roscommon, also Cheboygan, Mecosta (N & A 1932); EUP, Chippewa. 5. var. tatrica Racib. P1. 35, Fig. 2. West, West and Carter, 1923. Monogr. Brit. Desm. 5:234. P1. 162, Fig. 19. This variety is almost as long as wide, or longer than wide, the somewhat quadrangular cells having a dis- tinct median constriction. The filaments are often with- out mucilanginous sheaths. Measurements: L. 12-(13)-(15)-22; W. (15)-16-(17)-20u. Distribution: NLP, Roscommon; WUP, Gogebic. New record for Michigan. 6. Hyalotheca neglecta Racib. West, West and Carter, 1923. Monogr. Brit. Desm. 5:238. P1. 162, Figs. 11-15; Pl. 163, Figs. 1-4. This species is about 2 1/2 - 3 times longer than , wide, with the slightly tumid midregion of cells showing a slight median constriction. Measurements: L. 26-(29)-42u; W. ll-(15)-18.5u. Distribution: NLP, Cheboygan (N a A 1932); WUP, Gogebic. 514 7. Hyalotheca undulata Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:239. Pl. 162, Figs. 6-9. This species is characterized by the cells being 1 1/2 - 2 times longer than wide, and having a broad, shallow lateral indentation. The length of the cells is under 18u, this feature separating the species from some forms of S, neglecta which also has a broad, shallow indentation. Two transverse rows of mucilage pores are found on each semicell. Measurements: L. 8-(9)-(l2)-l7u; W. 5-(5.5)-(9)-9u. Distribution: SLP, Barry, also Calhoun (Pres. & Mag. 1935); WUP, Gogebic. 26. PHYMATODOCIS Nordstedt 1877 Cells quadrangular in front view, about as long as wide, joined together end to end in straight or spirally twisted filaments; median constriction deep and the sinus linear to sublinear; apices and lateral margins flattened or slightly undulate. Semicells in transverse view quadrate, with angles. extended to form arms which are broadly rounded at the apices. Chlordplast, axial and single in each semicell, with two rad- ially laminate plates extending into each arm. Zygospore irregularly quadrangular with irregularly thickened walls. 1. Phymatodocis Nordstedtiana fa. minor West and West P1. 14, Fig. 2. West and West, 1895. Trans. Linn. Soc. 5(5):230. P1. 12. 515 This very rare genus has quadrangular cells ar- ranged end to end to form straight or spirally twisted filaments. There is a deep median constriction and a linear to sublinear sinus. In vertical view, the cell is quadrate with the angles extended into broadly rounded arms. Measurements: L. 33-35.38.5u; w. 27-34.5-(35u)._ I. 11.5-15-(16u). Distribution: EUP, Chippewa; WUP, Gogebic. New record for Michigan. 27. DESMIDIUM c. A. Agardh 1824 Cells united into filaments, which are usually twisted, sometimes enclosed in a broad mucilaginous sheath. Cells usu- ally broader than long, and radially symmetrical, not markedly compressed; in front view semicells transversely semi-ellip- tical, trapeziform or narrowly oblong; median constriction usually distinct and moderately Shallow; apices plane or when depressed, forming an opening between adjacent cells; cells in vertical view broadly elliptic, cylindrical, sub-cylindri- cal, oblong, tri-or quadrangular; chloroplast, axial, single and central in each semicell, with lobes or plates (each with a pyrenoid) projecting into each angle. Zygospores spherical or ellipsoidal, wall smooth or with small flattened conical papilla. Key to Species of Desmidium Vertical view broadly elliptical, cylindrical or subcylindrical, often with a nodule at each pole . Vertical view otherwise . . . . . 2. Vertical view angular . . 2. Vertical view otherwise . . . Filaments twisted . . . . . . . Filaments not twisted . . . . . . 4. Vertical view quadrangular (syme metrical) . . . . . . . . . . 4. Vertical view triangular (very rarely quadrangular) or asym- metrically triangular . . . . Vertical view asymmetrically tri- angular . . . . . . . . . . . . Vertical View symmetrically tri- angular . . . . . . . . . . . . 6. Lateral margins convex in ver- tical view . . . . . . . . . 6. Lateral margins not convex in vertical view . . . . . . . Apices plane or nearly so, area be- tween apices of adjacent cells very small or none . . . . . . . Apices with broad depressions, area between apices of adjacent cells large and distinct . . . . . . 8. Median incision well defined 8. Median incision not well de- fined . O O O O C C O O C O 516 11 2 4 3 (11) S, pseudostrepto- nema (4) D. aptogonum var. Ehrenbergii (9) S, Swartzii var. quadrangulatum (l) S, asymmetricum 6 (13) S, aequale 7 9 8 (2) S, Aptogonum (5) S, Baileyi 11. ll. 13. 51? Semicells in front view transversely and narrowly oblong . . . . . . . 10 Semicells in front view transversely oblong semi-elliptical . . . . . . (6) S, occidentale 10. Spaces between apical adjoined processes transversely nar- row-oblong or linear, often difficult to detect . . . . . (7) D. Swartzii 10. Space between apical adjoined processes transversely ellip- tical, distinct . . . . . . . (11) 2, pseudostrepto- nema Cells 19-22u long by 25-29u wide . . (12) S, quadratum Cell measurements otherwise . . . . 12 12. Cells 17- 22u long by 29- 35H wide . . . . . . . . . . (13) S, aequale 12. Cell measurements otherwise . . 13 Width of apex of semicells one-third or less of the width of the cell at its greatest diameter . . . . . (14) S, coarctatum Width of apex of semicell more than one-third of the width of the cell _ at its greatest diameter . . . 14 14. Apex of semicell l6-24u wide . (15) D. coarctatum var. Eambricum l4. Apex of semicell 26-40u wide . (16) S, Grevillii Desmidium asymmetricum Gronbl. Gronblad, B., 1920. Acta. pro. Faun.et Flor. Fenn 47(4):85. Pl. 1., Figs. 5-7. This species in vertical view has triangular semi- cells that are assymmetrical. In front view, the lobes of the semicells lie in different planes because the cells within the filament are turned at various angles. 518 Measurements: L. 15.6-23.4; W. 27-28u. Distribution: Isle Royale (Prescott 1937, 1940). I 2. Desmidium Aptogonum Breb. West, West.and Carter, 1923. Monogr. Brit. Desm. 5:242. Pl. 164, Figs. 1-3. This species is the only one except 2, Baileyii that possesses a large elliptical cavity between adjacent cells. It can be separated easily from the latter by the marked constriction of the semicells. Measurements: L. l2-(l9.3)-20u; W. 21-(28)-43u; I. 14- (17)-35u. Distribution: Well distributed throughout States in writer's collections. SLP, Barry (2), Berrien, Jackson, Ingham, Washtenaw, also Wayne (Campbell (1886), Kalamazoo, Kent (N & A 1932) and Macomb (Pieters 1894); NLP, Che- boygan, Roscommon, Crawford, Emmet, also Cheboygan (N & A 1932); EUP, Alger, Mackinac, Schoolcraft, Chippewa (2); WUP, Marquette, Menominee, Houghton, Gogebic (2), also Isle Royale (Prescott 1937, 1940). 3. var. acutius Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:244. P1. 64, Fig. 6. The lateral angles of this variety are not rounded as in the typical, but are slightly retuse in the upper part, thus producing a sub-acute angle pointing toward the apex. Otherwise, the variety conforms to the typical. 519 Measurements: L. 15-(15)-23u; W. (28)-32-43u; I. (21)-34u. Distribution: SLP, Barry, Washtenaw, also Ingham (N & A 1932); NLP, Roscommon, Crawford; EUP, Chippewa, School- craft. 4. var. Ehrenbergii Kuetz. P1. 14, Fig. 3. West, West and Carter, 1923. Monogr. Brit. Desm. 5:243. P1. 164, Figs. 4, 5. This variety is not triangular in vertical view like the typical, but is oblong-rectangular, with rounded poles and with concave lower and convex upper lateral margins. Also unlike the typical form,the filaments are not twisted. Measurements: L. 14-(2l)-22u; W. 25-(32)e32.5u; I. 22-(22)-24u. Distribution: EUP, Alger; WUP, Menominie. New record for Michigan. 5- Desmidium Bailgyi (Ralfs.) Nordst. Smith, G. M., 1924. Wisc. Geo. and Nat. Hist. Surv. Bull. 57(2):145. P1. 88, Figs. 5-7. This species is sharply differentiated in front view by the rectangular shape of the cells, the almost ‘ straight (sometimes two very slight undulations) lateral margins with only a suggestion of a median constriction. It also has very pronounced elliptic cavities between adjacent cells that are also found in 2, Aptogpnum and its varieties. The variety minor Allorge and Allorge 520 appears to differ only in smaller size and is included here under the typical. Measurements: L. 15-(2l.5)-26u; W. 19-(2l.5)-30u. Distribution: SLP, Barry (2), also Kalamazoo (N & A 1932), Wayne (Campbell 1886) and Macomb (Pieters 1894); NLP, Cheboygan (N & A 1932); EUP, Alger, Delta, Schoolcraft (2), also Schoolcraft (Transeau 1917); WUP, Menominee, Gogebic; Isle Royale, (Prescott 1937. 1940?(2, Baileyi var. EiflEE)’ 6. Desmidium occidentale West and West P1. 35, Fig. l. West, West and Carter, 1923. Monogr. Brit. Desm. 5:245. P1. 164, Fig. 11. This species is close to S, Swartzii from which it is separated by the semi-elliptic shape of the semicells. It is proportionately longer and the lateral angles are shorter and more rounded. The Michigan specimens are smaller than measurements given by West, West and Carter (1923). Measurements: L. (21.5)-25.5-28u; W. (29)-32.5-38.5; I. (21.5)-23-38.5u. Distribution: Eup, Delta. New record for Michigan. 7. Desmidium Swartzii C. A. Agardh West, West and Carter, 1923. Monogr. Brit. Desm. 5:246. Pl. 163, Figs. 5-8. Characteristically, this species has transversely narrow, long, trapeziform semicells with lateral margins obliquely truncate. The upper lateral margins are dis- 521 tinctly projected toward the apex and the lower lateral margin is generally rounded. The space between the a- pices of adjoined cells is often difficult to distinguish. Measurements: L. 12-(17.5)-2o.5; w. (34.3)-35-(39)- 50u; I. 27-(34)-40u. Distribution: One of the most common and wide-spread species in Michigan. SLP, Barry (3), Ingham, Washtenaw, also Ingham, Kalamazoo, Kent, Mecosta, Muskegon, Newaygo, Ottawa (N & A 1932). Muskegon (Transeau 1917 and Macomb (Pieters 1894); NLP, Roscommon, Crawford, Emmet, also Cheboygan N & A 1932), Cheboygan (Welch 1936b, 1938a); EUP, Chippewa, Mackinac, Alger, Delta also Chippewa, Mackinac, Schoolcraft, Luce (N & A 1932), Schoolcraft (Transeau 1917); WUP, Menominee, Gogebic (5), Marquette, Houghton, also Dickinson, Houghton, Ontanagon (N & A 1932); Isle Royale (Prescott, 1937, 1940). 8. var. amblyodon Rabenh. West, West and Carter, 1923. Monogr. Brit. Desm. 5:249. P1. 165, Fig. 7. This variety is separated from the typical form by its possession of rounded lateral margins. Measurements: L. l5-2lu; W. 30-50u; I. 25-45u. Distribution: NLP, Newaygo (N & A 1932). 9. var. quadrangulatum (Ralfs.) Roy West, West and Carter, 1923. Monogr. Brit. Desm. 5:248. P1. 163, Figs. 9, 10. 522 This variety differs from the typical in being quadrangular in vertical view and in having a much greater width. Measurements: L. 24.8u; W. 57.6-60u. Distribution: NLP, Cheboygan, Presque Isle (Taft 1939). 10. var. spinuosum Ackley Ackley A., 1929. Trans. Amer. Microsc. Soc. 48:304. P1. 35. Fig. 13- This variety has been described by Ackley (1929) as possessing numerous short spines at all the lateral angles. The writer has not seen such a form in his col- lections, although frequently some specimens were found to have mucilage threads extruded from the cells, Simu- lating Spinous-projections. More specimens of this or- ganism must be collected and examined before it can be considered valid. Measurements: L. l7-2lu; W. 31-37u; I. 28-30u. Distribution: Ackley (1929) reports having collected this variety from near Augusta, Michigan which is in Barry County. However, in (1932) She reports the same variety as occurring only from Newaygo County. 11. Desmidium pseudostreptonema West and West West, West and Carter, 1923. Monogr. Brit. Desm. 5:244. P1. 165, Figs. 5, 6. Characteristically, this species has transversely and narrowly oblong semicells with rounded lateral mar- 523 gins. The cells are about one and one-half to two times wider than long. The apex is convex resulting in a small elliptical space between the apices of ad- jacent cell attachment regions. The vertical view is either triangular or oblong, the latter being bilobed with a slight constriction between each angle. This species resembles Spondylosium pulchrum (Bailey) Archer and S, Swartzii var. amblyodon,Rabehn. superficially. It is separated from the former by the connecting pro- cesses on the apices and from the latter by the shape and size of the Space between the apices of adjacent cells. The triangular form was not found in the writer's collections. Measurements: L. l7-(20.7)-21u; W. 31-(34.5)-35u; I. 13.5-22-(25u). Distribution: NLP, Cheboygan (N & A 1932); EUP, School- craft, Delta, Alger; WUP, Menominee. l2. Desmidium quadratum Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:254. P1. 166, Figs. 6, 7. This Species is closely related to 2, aeguale West and West from.which it is separated by the greater width. (See discussion under 2, aequale for characteristics of this species.) ' Measurements: L. 19-(22)-22u; W. 25-(27)-29u. Distribution: SLP, Livingston, also Jackson (N & A 1932); 524 NLP, Roscommon, also Cheboygan (N & A 1932); EUP, Chip- pewa, also Chippewa (N & A 1932). 13. Desmidium aequale West and West West and West, 1896. Trans. Linn. Soc. of Lon., Bot. 5(5):233. P1. 12, Figs. 17, 26. This species is closely related to 2, quadratum Nordst. from which it is separated by the greater width of the semicells. In vertical view 2, gpadratum is sub- circalar whereas 2, aequale may be subcircular or trian- gular (with convex margins). A nodule is at each pole in both species. The cell proportions give 2, aequale, in front view, a transversely narrow oblong shape while 2, gpadratum has a short pyramidate truncate shape. Measurements: L. 17—l9u; W. 29-35u; I. 28u. Distribution: NLP, Cheboygan (N & A 1932). 14. Desmidium coarctatum Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:252. Pl. 165, Figs. 1, 2. Cells elliptical, from about one and one-half to two times broader than long, with a narrow apex about one-third the width, and with a slight median constric- tion. The vertical view is usually narrowly elliptical with a nodule at each pole. The cell wall has several longitudinal rows of minute punctae. Measurements: L. 25-34u; W. 34-38-(42); I. 33-(35); A. 12-14-(15). 525 Distribution: SLP, Livingston; NLP, Roscommon, also Cheboygan (N & A 1932). 15. var. cambricum W. West. West, West and Carter, 1923. Monogr. Brit. Desm. 5:252. Pl. 165, Figs. 3, 4. This variety differs from the typical in the dif- ferent prOportions of the cell, and in the greater width of the apex. It approaches 2, Grevillii (Kuetz.) De Bary in general form but the apex is always shorter than the latter. Measurements: L. 22.5-24u; W. 40-45u; I. 35-37u; A.16-24u. Distribution: SLP, Calhoun (Pres. & Mag. 1935). 16. Desmidium Grevillii (Kuetz.) De Bary West, West and Carter, 1923. Monogr. Brit. Desm. 5:249. Pl. 164, Figs. 7-10. The use of Ralfs (1848) as a starting point for nomenclature necessitates the use of this name Grevillii although 2, cylindricum antedates it. Characteristically, this species has short pyramadate truncate cells, at least twice as wide as long, plane ap- ical attachment and, in vertical view, an elliptical shape with a nodule at each pole. It is closest to S, coarctatum var. cambricum W. West from which it differs by the greater width of the apex. Measurements: L. 20-(26.5)-(27.5); W. (40)-41-(44)-63; I- (34)-35-(37)-47u; A. 26-40u. 526 Distribution: Well-distributed throughout the state in the writer's collections. SLP, Barry (3) also Muskegon (Transeau 1917); NLP, Crawford, also Cheboygan (N & A 1932, Welch 1936b); EUP, Chippewa (2); WUP, Gogebic (3), Houghton; Isle Royale (Prescott 1937, 1940). 28. GYMNOZYGA Ehrenb. 1841 Cells cylindrical or barrel-shaped, always longer than wide, joined together in long, untwisted (rarely twisted) filaments, median constriction very slight, basal part of the semicells usually inflated; apices flattened and without pro- tuberances. The cell wall is smooth or with longitudinal striae near the poles. Cells in transverse view circular with two opposite mammillae. Chloroplasts axial with radiating longitudinal plates; each chloroplast with a single centrally located pyrenoid. Zygospore smooth, spherical to broadly ellipsoidal. 1. gymnozyga moniliformis Ehrenb. West, West and Carter, 1923. Monogr. Brit. Desm. 5:255. Pl. 165, Figs. 8, 9. This organism is the only species of Gymozyga re- ported as yet from.Michigan. It is chiefly character- ized by the barrel-shaped cells joined together in long untwisted filaments. A slight median constriction is present and the basal part of the semicells is inflated. The cell wall has a series of longitudinal striae near the pole. 527 Measurements: L. 20-(28)-37u; w. 16.5-(19)-(2l.5)-26u. Distribution: Very common and widespread in writer's collections. SLP, Barry (3), Calhoun, Livingston, also Kalamazoo (N & A 1932), and Muskegon (Transeau 1917); NLP, Cheboygan, also Cheboygan (N & A 1932, Welch 1936a, 1936b), Emmet (N a A 1932); EUP, Delta (2), Alger, Chip- pewa, Schoolcraft, also Mackinac (Transeau 1917); WUP, Gogebic (4), Marquette, Menominee, Baraga, Houghton (2), also Ontanagon (N & A 1932); Isle Royale (Prescott 1937). 2. var. gracilescens Nordst. West, West and Carter, 1923. Monogr. Brit. Desm. 5:256. Pl. 165, Fig. 10; Pl. 166, Fig. 10. This variety has a relatively smaller width than the typical. Measurements: L. 24-(26)-30u; W. l3-(15)-17u. Distribution: SLP, Barry; NLP, Crawford, also Cheboygan (N a A 1932); EUP, Alger. 538 XII. BIBLIOGRAPHY Ackley, A., 1929. New Species and varieties of Michigan algae. Trans. Amer. Microsc. Soc., 48:302-308. 2 phi Bernard, 0., 1909. Sur quelques algues unicellulaires d'eau douce recoltees dans le domaine Malais. Dep. do L'Agric. aux Ind. Neerland. Buitenzorg. 9h pp. 6 pls. Boergesen, F., 1890. Desmideae brasilieae: Symbolae ad F1. Bras. Centr. Cognosc. ed. E. Warming particula 34. Vid. Medd. Nat. For1., (1890):929-958. P1. 2-5. Borge, 0., 1918. Die von Dr. A. Lofgren in Sao Paulo gesammelten Susswasseralgen. Ark. f. Bot., 15:1-108. , 1921. Die Algenflora des Takernsees. Sjon TEEerns Fauna och Flora utgiven av K. Svenska Vet., C1921):3-48 o 3 figs- , 1923. Bietrage zur Algenflora von Schweden. Ark. ?. Beto, 18:10.3“. 2 p13. , 1925. Die von Dr. F. C. Hoehne wahrend der der Expedition Roosevelt-Rondon gessamelten Susswasser- 318311. Ark. f. B0130, 19 (17):].‘560 , 1930. 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Sci., Arts, and Letters, 27:27-36. Heimerl, A., 1891. Desmidaceae alpinae. Ver. k. k. Zool- Bot. Gas. in Wien: 41. 587-609. Pl. 5. Hirano, M., 1949. Some new or noteworthy Desmids from Japan. Acta. Phytotaxon. et Geobotan., 14 (l):1-4. Hirn, K. E., 1903. Zur Kenntnis der Desmidiaceen Finnlands. Acta Soc. Fauna et Flora Fenn., :1-24. 2 pls. Homfeld, 1929. Bietrag zur Kenntnis dor Desmidiaceen nordwestdeutschlands besonder ihrer Zygoten. Pflanzen- forschung, 12:1-97. 9 pls. 530 Insam, J. and Krieger, W., 1936. Zur verbreitung der gattung Cosmarium in Sud-tirol. Hedwigia, 76:95-113. p130 ' Irenee-Mario, Frere, 1938. Flora desmidale do la region do Montreal. La Prarie. 547 pp. 69 pls. , 19u8. Contribution a la connaissance dos DesmidiEos do la region dos Trois-Rivieros. Le Nat. Can., 75:139-173. 3 pls. , 1949. Contribution a la connaissance dés Dosmidieos do 1a region dos Trois-Rivieros. Lo Nat. Can., 76:16-u2. 4 p18. g , 1949. Quolquos Dosmidioes du lac Mszatassini. Lo Nat. Can., 76:2u2-26l, 265-316. , 1951. Dosmidieos do la region do Quoboc. Lo Nat. Can., 78:88-127. , 1952. Dosmidiees do 1a region do QuebSCQ Le Nat. Can., 79 (l):ll-u5. Jewell, M. E. and Brown, H. W., 1929. Studies on Northern Michigan Bog Lakes. Ecology, 10:427-475. Johnson, L. N., 1894. Some new and rare Desmids of the United States. I. Bull. Torr. Bot. Club., 21 (7):285- 2910 1 p10 , 1895. Some new and rare desmids of the United States. II. Bull. Torr. Bot. Club, 22:289-298. 2 p130 Joshua, W., 1885. On some new and rare Desmideae. III. Jour. Bot., 23 (2):33-35. P1. 254. Krieger, W., 1932. Die Desmidiaeceen dor Deutschos Limnologischons Sunda EXpedition. Arch. f. Hydrobiol., 11:129-230. 25 pls. , 1933-1937. Die Desmidaceon EurOpas mit Boruéksfchtigung dor aussorouropaischen Arton aus Rabenhorst's Kryptogamonflora von Deutsohlands, Ostor- reich und der Schweiz, 13 (1):1-375. P1. 1-96. , 1939. Die Desmidaceon Europas mit Beruck- sichtigung dor aussoreurOpaischen Arten. Dr. L. Rabonhorst's Kryptogamenflora von Deutschlands, Oster- reich und der Schwotz, 13 (2):1-117. P1. 97-142o Lagerheim, G., 1885. Bidrag till Amerikas Desmidioflora. Ofvers. Kgl. Sv. Vot.dlkad Forh., 42 (7):225-255. P1 27. 531 , 1887. Kritische Bormerkungon zu einigen in den‘Ietiten Jahren boscrriebenen Arton und Varietaten von Desmidiaceen. Ofvers. K. Sv. Vet. Akad. Forh., 8: 535-541. LaPorte, L. J., 1931. Recherches sur la biologic et la systomatiquo des Desmidieos. Encyc. Biol., 9:150 pp. 22 p180 Leverett, F., 1917. Surface Geology and Agricultural Conditions of Michigan. Mich. Goo. and Bio. Surv. Publ. 25, Geo. Series 21. 215 pp. 15 pls, 25 figs. Lundell, P. M., 1871. De Desmidiaceis quao in Suecia inventao sunt observationes criticao. Nov. Acta Rog. Soc. Sci. Upsale, III., 8 (2):100 pp. 5 pls. McIntoor, B. B., 1938. Distribution of the algae of Kentucky in relation to soil regions. Castanoa: Jour. So. App. Bot. Club., 3:33-35. Messikommer, E., 1927. Biologische Studien im Torfmoor von Robonhauson untor bosondorer Beruckschtigung. Inaugr. Dissort. Mitt. Botan. Mus. Univ. Zurich, 122: 1'1710 6 p13, 1 fig. , 1938. Bietrag zur Kenntnis der Fossilen und sfib-fossilon desmidacoon. Hedwigia, 78:107-201. 9 pls, 1 fig. Millar, E. C. Soils of Michigan. Extension Bull. 290. COOporative Ext. Sorv. Mich. State College. Neel, J. K., l9h8. A limnological investigation of the Psammon in Douglas Lake, Michigan with sapocial reference to shoal and shoreline dynamics. Trans. Amer. Microsc. 50°C: 67 (1)31'330 Nichols, G. E. and Ackley, A. B., 1932. The Desmids of Michigan, with particular reference to the Douglas Lake region. Pap. Mich. Acad. Sci., Arts, and Letters, 15:113-1H0. Nordstedt, C. F. 0., 1878. De algos aquae dulcos ct do Characeis ex insulis Sandviconsibus a Sv. Borggren 1875 reportatis. Minn. Utg. F siogr. Sallsk. Lund, i anlodn. af dess hundraarsfest., 1 78:1-24. 2 pls. , 1888. Freshwater algae collected by wDr. S. Borggren in New Zealand and Australia. Kongl. Vet. Akad. Handl., 22:1-18. 7 pls. , 1895. Index Desmidacearum. Lundae. h“ 3I0 pp. [C 532 Okada, Y., 1934. The desmid-flora of the northern Kurilo Island. Jour. Imp. Fis. Inst. (Tokyo), 30:123-199. 15 pls, 10 figs. ’ Pearsall, W. H., 1921. A suggestion as to factors in- fluencing the distribution of free-floating vegetation. Jour. E0010, 932141-2530 , 1932. PhytOplankton of the English Lake District. II. The composition of the phytOplankton in relation to the dissolved substances. Jour. Ecol., 20:2“.1-2620 Pennak, R. W., 1946. The dynamics of fresh water plankton' pOpulations. Ecol. Monogr., 16:339-356. Pieters, A. J., 1894. Plants of Lake St. Clair. Bull. MiCho FiSh COMQ, 2:1'120 1 p10 Prescott, G. W., 1935. Notes on the dosmid.flora of New England. II. Desmids from Cape Cod and the Elizabeth Island. Rhodora, 37:113-121. P1. 12. , 1937. Preliminary notes on the doSmids of IsIo‘Hoyale, Mich. Pap. Mich. Acad. Sci., Arts, and Letters, 22:201-213. P1. 19. , 1938. Further notes on the desmids of IsIe RoyaIe, Mich. The genus Cosmarium. Paper. Mich. Acad. Sci., Arts, and Letters, 25:205-214. 4 pls. , 1939. Some relationships of phytOplankton to’lfmn6Iogy and aquatic biology. Problems in Lake biology. Amer. Assoc. Adv. Sci. Pub1., 10:65-78. Figs. , 1940. Desmids of Isle Royale, Michigan. “*The genera Staurastrum, Micrasterias, Xanthidium, and Euastrum, with a note on SpinocIosterium. Pap. Mich. Acad. Sci., Arts, and Letters, 25:23-30. 2 pls. , 1941. A concluding list of desmids from ‘ISIo RoyaIe, Michigan. Pap. Mich. Acad. Sci., Arts, and Letters, 26:23-30. 2 pls. , 1948. Desmids. Bot. Rev., 14 (10):644- 676. , 1951. Algae of the Western Great Lakes area, exclusive of Desmids and Diatoms. Cranbrook Institute of Science Bull. 3l:xiii and 946 pp. 136 pls. __, and Magnotta, A., 1935. Notes of Michigan desmids with descriptions of some Species and varieties new to science. Pap. Mich. Acad. Sci., Arts, and Letters, 20:157-170. 3 pls. 533 and Scott, A. M., 1942. Desmids from lMissISsippI'with descriptions of new Species and varieties. Trans. Amer. Microsc. Soc., 61:1-29. 3 pls. . , 1943. The desmid genus Micrasterias Agardh‘In southeastern United States. FEp. Mich. Acad. Sci., Arts, and Letters, 28 (1942): 67-82. 6 p18. g , 1945. The freshwater algae o? southern Unitéd States. III. The desmid genus Euastrum, with descriptions of some new varieties. Amer. Mid. Nat., 34:231-237. 8 pls. Raciborski, M., 1889. Dosmidyje nowo. Pam. Wydz. Mat.- Przyro Akad. Umiejo, 1731-3; 73'113;l"u.10 ,3 p180 Schmidle, W., 1893. Algon aus dom Geboito dos Oberrheins. Ber. d. Deutsch Bot. Gesell., 11:544-555. 1 p1. , 1895. Beitrage zur Alpinom Algenflora. fiSterro BOto Zeit., u531‘380 L‘- p18, 1 fig.‘ 2449-253; 305-311; 346-350. 2 pls.; 387-391. , 1898. Uber einigo von Knut Bohlin in Pite Lappmafk und Vesterbotten gosammelte Susswasseral on. Bihang till K. Sven. Vet. Akad. Handl., 24 (3):2- 9. 3 p18. Scott, I. D., 1921. Inland lakes of Michigan. Mich. Goo. and Biol. Surv. Publ. 30, Geo. Series 25. 371 pp. 20 pls, 93 figs. Scott, A. M. and Prescott, G. W., 1949. Spinocosmarium quadridens (Wood) Pros. and Scott and its varieties. Trans. Amer. Microsc. Soc., 68 (4):342-349. P1. 1-2. Shoup, C. S., 1947. Geochemical interpretations of water analysis from Tennessee streams. Trans. Am. Fish Soc., 74-(1944). Skuja, H., 1928. Vorarbeiton zu einer algenflora von Lettlands IV. Acta Horti Bot. Univ. Latvionsis, 3: 103-218. 4 pls, 1 fig. , 1930. Algae Botanische Ergebnisse dor Doutschon Zentralasien Ex edition 1927-1928. Mitt. Bot. Mus. der Univ. Zurich, 1 3:1-76. 1 pl. Smith, G. M., 1924a. PhytOplankton of the inland lakes of Wisconsin. II. Desmidiaceae. Wis. Goo. and Nat. Hist. Surv. Bull. 57 (2):227 pp. 37 pls, 17 figs. 534 , 1924 b. Ecology of the plankton algae of the Palisades Interstate Park, including the relation of control methods of fish culture. Roos. Wild Life Bull., 2:93‘1950 2’4. p180 , 1933. The freshwater algae of the United States. McGraw-Hill Book Co., Inc., New York and London. 716 pp. 449 figs. Strom, K. M., 1919. Freshwater algae from Tuddal in Telemark. Nyt. Mag. f. Naturv., 57:143-195. 3 pls. , 1926. Norwegian Mountain algae. Skrift. Utgi, av Det. Norske Vidensk-Akad. i Oslo I. Mat. Nat. Kl., 6:1-263. 25 pls. Taft, C. E., 1939. Additions to the algae of Michigan. Bull. Torr. Bot. Club, 66:77-85. , 1945. The desmids of the west end of Lake Efio. ‘0hio Jour. Sci., 45:180-205. 5 pls. Taylor, W. H., 1934. The freshwater algae of New Found- land, Part I. Pap. Mich. Acad. Sci., Arts, and Letters, 19:217-278 (1933). 13 pls. , 1935a. The freshwater algae of New Found- ‘Iand, Part II. Pap. Mich. Acad. Sci., Arts, and Letters, 20:185-229 (1934). 17 pls. , 1935b. Phytoplankton of Isle Royale. Trans. Amer. MiErosc. Soc., 54:83-97. 4 pls. Telling, E., 1948. Staurodosmus, genus novum. Bot. Not., 194 :49-83. 72 figs. , 1950. Radiation of desmids, its origin and its consequences as regards taxonomy and nomenclature. Bot. Not., 1950:299-327. Figs. 1-34- Theroux, F. H., Eldridge, E. D., and Mallman, W. L., 1943. Laboratory manual for chemical and bacterial analysis of water and sewage. McGraw-Hill Book Co. Inc., New York and London. x and 274 pp. Transeau, E. N., 1917. The algae of Michigan. Ohio Jour. 301 o g 17 3 217-2320 Turner, W. B., 1892. Algae aquae dulcos Indiae orientalos. Kongl. Sv. Vet. Akad. Handl., 25 (5):l-187. 23 pls. Veateh, J. 0,, 1937. Geology in relation to Peddlogy. Pap. Mich. Acad. Sci., Arts, and.Letters, 23:503-505. 1 map. 535 , 1941. Agricultural land classification and land types of Michigan. Spec. Bull. 231 (First Revision) October, 1941. Agr. EXp. Sta. Mich. State College. 67 pp. 1 map. Wade, W., 1949. Some notes on the algal ecology of a Michigan Lake. Hydrobiologia, 2 (2):109-117. Wailes, G. H., 1933. Protozoa and algae from Mount HOpeless, B. C. Art, Hist., and Sci. Assoc., Vancouver City'Museum. Welch, P. S., 1935. Limnology. McGraw-Hill Book Co. Inc., NGW'YOPK and London. , 1936a. Limnological investigation of a strongly basic bog lake surrounded by an extensive acid-forming bog mat. Pap. Mich. Acad. Sci., Arts, and Letters, 21 (l935):727-751. , 1936b. A limnological study of a small Sphagnum-1eather-leaf-black Spruce bog lake with Special reference to its plankton. Trans. Amer. Microsc. Soc., 55:300-312. , 1938a. A limnological study of a bog lake which has never deve10ped a marginal mat. Trans. Amer. Microsc. Soc., 57:344-357. , 1938b. A limnological study of a retro- gradingbog lake. Ecology, 19:435-453. Fig. 1, 3 tables. Wesenberg-Lund, 0., 1905. Comparative study of the lakes of Scotland and Denmark. Proc. Roy. Soc. Edinburg, 25 2 (4.01 -L(.L).8 0 West, G. s., 1914. A contribution to our knowledge of the freshwater algae of Colombia. In: Fuhrman, 0., and Mayor, E., Voyage d'eXploration scientifique in Colombia; Ncuchatel, Attenger Freres, 5:1013-1051. 3 pls. West, W., 1889. List of Desmids from Massachusetts, U.S.A. Jour. Roy. Microsc. Soc., 5:16-21. 2 pls. and West, G. 3., 1896. On some North American Desmideae. Trans. Linn. Soc. of Lon. Bot., II (5): 229-274. 7 pls. . __, 1897. Welwitsch's African TreShwater algae. Jour. Bot., 35 (412):1-78. 6 pls. , 1898. On some desmids of the United StaEES. Jour. Linn. Soc. Bot.. 33:279-322. 3 p13. ‘.w'> a O . U I K a O I 0 ‘ t . 536 pg), 1902. A contribution to the Freshwater algae of Ceylon. Trans. Linn. Soc. Bot., and Ser., 63123-2150 7 p13. . , 1904. A monograph of the BritiSh Desmidiaeceae. Roy. Soc. London, 1:224 pp. 32 p150 , 1905. A monograph of the British Desmidiaeceae. 'Roy. Soc. London, 2:204 pp. 32 pls. , 1906. A comparative study of the plankton 0? some Irish lakes. Trans. Roy. Irish Acad.. 33:77—116. 6 pls. , 1908. A monograph of the British Desmidiaeceae. Roy. Soc. London, 3:274 pp. 21 pls. , 1909. The British freshwater phytOplankton with Special reference to the desmid plankton and the distribution of British Desmids. Proc. Roy. Soc. London, B, 81:165-206. ' , 1912. A monograph of the British Desmidifieoeae. *Roy. Soc. London, 4:191 pp. 32 pls. and Carter; N., 1923. A mono raph cg the British Desmidiaeceae. Roy. Soc. London, 5:269 pp. 2 p13. Whelden, R. M., 1943. Notes on New England algae. III. Some interesting algae from Maine. Farlowia, 1:9-23. 18 £188. Wolle, F., 1884. Desmids of the United States and a list of American Pediastrums with eleven hundred illustrations on fifty-three calored plates. Bethlehem, Pa. 14 and 168 pp. 53 pls. , 1892. Desmids of the United States and list 0 American Pediastrums. Bethlehem, Pa. 10 and 182 pp. 6L1 p13. XIII. COLLECTI 0N DATA Southern lowor_peninsula Barry county Otis lake Unnamed bog lake on Quinby Rd. South and west of Hastings Small marshy pond on Whittemore Rd. East of Otis lake Unnamed bog lake between Dalton and Hickory corners Perch lake Berrien county Mud lake bog (collections furnished by M. L. Britton) Koenigshof lake (collected by Mr. Koenigshof) Calhoun county Winipeg lake (sometimes called Calhoun lake) Swampy bog near Battle Creek (collected by G. W. Prescott) Clinton county Park lake (mat collections only) Ingham county Mud lake near Holt Ewers lake Huntoon lake Bear lake Three lakes Jackson county Squeezings from mosses in swale - Waterloo area Brill lake Little Pleasant (Weilch) lake Huckleberry marsh south of Little Pleasant lake Goose lake - Mat on west shore Small unnamed lake near Cloverleaf east of Jackson on U030 #12 Livingston county Old marsh east of Fowlerville on U.S. #16 Unnamed bog lake south and east of Howell Oakland county Softwater lake Golfcourse pond - Webster Walters lake Pungs lake Small lake east of Pungs lake Shiawassee county Burke lake Shallow "pot-hole" between hills near Burke lake Rose lake Washtenaw county Small ”pot-holes" on both sides of Territorial Rd. west of Hudson Mills Mud lake - Waterloo area L“? .Ja’ Small unnamed lake in Waterloo area Cavanagh lake - Waterloo area Whittemore lake bog - (Dead lake ?) Northern lowergpeninsula Cheboygan county East Twin lake West Twin lake Little lake 16 Crawford county In brush near Beaver Creek Wakely lake east of Gaylord Kalkaska county Twenty One lake - On Michigan Rt. #66 south of Kalkaska Roscommon county Robinson lake Roadside ditch near Robinson lake Eastern upper_peninsula Alger county Marshland by Munising county park Chippewa county Unnamed lake beside road from Paradise to Tahquamenon Falha Mud lake on Rt. #2 near Rudyard CLO J Delta county Second lake Unnamed bog lake north of Harris Au Train swamp Mackinac county Old marshland on U.S. #2 west of St. Ignace Cedar and Tammarack woods along U.S. #2 west of St. Ignace Schoolcraft county Cedar lake Crane lake Doyle lake Marshland near Seney Marsh along Rt. #9# north of Manistique (collected by G. W. Prescott) Western upper_peninsula Gogebic county Swamp along road north of Fuller Baraga county Vast Tammarack marsh between L'anse and Marquette on Rt. #28 & kl Bog lake near fish hatchery at Fuller (collected by G. W. Prescott) Marsh east of Watersmeet near Gun lake 5&1 Marshland along railroad tracks Cloverleaf lake near Cisco lake Small unnamed lake near Cloverleaf lake Houghton county Small unnamed lake on Rt. #26 south of Houghton and east of Baraga Iron county Beaver lake Keweenaw county Unnamed bog lake along Rt. #41 west of COpper Harbor Low marshland adjacent to Objibway cepper mine near Vaughnsville Marquette county Marshland along Rt. #ul west of Ishpeming Swamp five miles west of Ishpeming (collected by G. W. Prescott) Pond at base of Sugarloaf Mountain. 542 XIV . PLATES 1. 2. 3. u. 5. 6. 7. 8. 9. 10. 11. 12. 13. Pl ate 1 Mogotaenium Endlicherianug Naeg. Cylindrocyécig crassa DeBary. Mg cambrica West and West fa. R. obtusa var. montana West and West. Penium polymorph_u_m_ Party. Closterium; acuity; var. variable (Lemm.) Kriegom _C_l_._. Subulatum (Kuetz.) Breb. 91;. prononum Breb. 93... prononum Breb. _C_l_._. Subscoticgg Gutw. Q. Baillyanum var. alpinum (Viret) Gronblad ta. 9;. didymocotgm var. glabrum Barge. 9.1: BEBE V315 _1‘°_b..fi.,8tmn (G. S. West) Krieger- l. 3. 1+. 5. 6. 7. 8. aster-13m juncidum var. elongatum 9;. 9;. 9;. 9;. 9;. 9;. 9;. Plate 2 p_r_aelongum Breb. idiosporum West and West lineatum var. costatum Wolle ulna Focke. costatum var. Westii Cushman Braunii Reinsch Brauni i Reinsch Roy and Biss. CI, l. 2. 3. 5. Plate 3 Closterium cynthia DeNot. El. calquorum var. brasiliense Boerg. El- W var. subcostatum (Nordst.) Krieger 9;. venus var. verrucosum (Roll) Krieger 9;. Ralfsii Breb. fa. \\ I! If H H 1!an M H“. . .'. .' 1. 2. 3. 1L. 5. 6. Plate 1|. Pleurotaenium constrictum (Bailey) Wood. _P_l_. trabecula var. rectissimum West and West. 31;. subcommulam var. 933313 West and West. fl. minutum var. gracile Wille. Pl. verrucosum (Bailey) Lund. Pl. minutum (Ralfs) Delp. ”DO-"mu— 1. 2. 3. LL. 5. 6. 7. 8. Plate 5 Triploceras verticillatum Bailey Euastrum cuneatum var. subansatum Kossinsk. E. ansatum fa. Scottii nob. E. ansatum var. submaximum Borge E. pingue Elfv. 'E. sublobatum var. obtusatum (Gutw.) Krieger E. sublobatum Nordst. E. validum var. glabrum Krieger 1. 2. 3. u. S. 6. 7. 8. 9. 10. 11. Plate 6 Euastrum intermedium var. longicolle Barge. E. intermedium Cleve fa. E. binale (Turp.) Ehrenb. (E. sibiricum Boldt. ‘E. sinuosum var. aboense (Elfv.) Cedegr. E. oculatum var. tonsum‘West and.West. .§° denticulatum var. angusticeps Gronblad. E. bipapillatum Gronblad. ‘E. abruptum Nordst. E. lapponicum Schmidle fa. E. Ciastonii Racib. 1. 2. 3. LL. 5. 6. 7. 8. 9. 10. 11. Plate 7 Euastrum verrucosum var. alatum (Ehrenb.) Wolle. E. W var. W (Racib.) West and West. E. evolutum var. Glaziovii Barge. Arthrodesmus impar (Jacobs) Gronbl. E. _t__e'nui ssinlgg Archer. "1’ triSpinatus West and West. __-—‘ I? O crassus West and West fa. Borge. “1’ controversus var. brasiliense Borge. ——i I'P O _i_._I_1_0_1_1_§_ var. longi spine Ei chl . and Racib. I? O incus fa. semilunaris Schmidle. l‘P O Ergangulagig; Lagerheim. 1. 2. 3. LL. 5. Plate 8 Arthrodesmus curvatus var. minor var. nov. 5, Ralfsii var. Brebissonii (Racib.) Smith. Xanthidium obsoletum Taylor. ‘E. cristatum var. Hippargui Irenee-Marie. E. tetracentrotum var. intermedia var. nov. Pl. 8 ”Qt 1U; ' sf!" slat-u?“ 1. 2. 3. Plate 9 Xanthidium cristatum fa. mucronata West and West. E. cristatum var. papilliferum Irenee—Marie. E. antiEopaeum var. basiornatum Eichl. and Racib. Plate 10 1. Xanthidium antiIOpaeum var. oligacanthum Schmidle. 2. E. subhastiferum var. Johnsonii fa. Smithii fa. nov. P1. 10 midi—Kw- ' 6.7m34“«'1~!§| 9 e , . ' ' e e O I e Plate 11 l. Xanthidium antiloPaeum fa. michiganensis fa. nov. 2. E. antiIOpaeum var. triquetrum Lund. 3. Spinocosmarium guadridens (Wood) Pres. and Scott. P1. 11 Plate 12 l. Micrasterias Nordstedtiana Wolle. 2. fl. radiata var. pseudocrux Gronblad fa. \— Plate 13 l. Micrasterias truncata var. semiradiata (Naeg.)Clmm. 2. E. truncata var. guadrata Bulnh. 15 —‘..A‘_- ”- _ _.——.—\ A ~-........-’// l. 2. 3. Plate lu Micrasterias papillifera var. Speciosa (Wolle) Krieger. Phymatodocis Nordstedtiana fa. minor West and West. Desmidium Aptogonum var. Ehrenbergii Kuetz. l. 2. 3. LI». 5. 6. 7. 8. 9. Plate 15 Cosmarium cyclicum var. Nordstedtianum (Reinsch) West and West. E. ocellatum Eich. and Gutw. fa. E. cucumis (Corda) Ralfs. 9. moniliforme fa. punctata Lagerh. _C_. moniliforme fa. ‘panduriformis Heimerl. Q. canadense Irenee-Marie. _Q. moniliforme var. subpyriforme West and West. 9. moniliforme fa. elongata West and West. 9. depressum var. achondrum (Boldt) West and Waste . - . " . I .-. ' e _ . ' - , e ‘ _ . . - e ’ _ 9 e 0 ' _ . . - - C . . . ._ e v - . ' _ e- ~ . . ~ - . e D . O .. "'P‘-. I 1. 2. 3. LL. 5. 6. 7. 8. 9. 1o. 11. 12. 13. 1L1. 15. 16. Plate 16 Cosmarium subdepressum West and West. 9. phaseolus fa. $3333 Boldt. E. phaseolus var. elevatum Nordst. E. bioculatum var. EEEQ§9West and West. 9. trilobulatum var. basichondrum Nordst. IQ . Pokornyanum (Grun.) West and West. variolatum var. cataractarum Racib. fa. IO 0 IO 0 trilobulatum fa. retusa Reinsch. IO 0 arctoum var. tatrica Racib. IO 0 minimum West and West. lo 0 an ulare var. octangulare var. nov. IO 0 pseudopyramidatum var. stenonotum Nordst. IO 0 variolatum Lund. fa. IO 0 bireme Nordst. IQ . geometricum var. suecium Borge. Q. galeritum Nordst. l. 2. 3. 5. 6. 7. 8. 9. 10. 11. 12. 13. 1k. 15. 16. 17. 18. 19. 20. Plate 17 t. Cosmarium pseudonitidulfl var. validum West and W65 9_. 9. 9_. IO lo I0 I0 I0 IO lo I0 IO I0 l0 I0 l0 I0 I0 IO 0 O O O o o o O 0 o o o e o e 0 pseudOpyramidatgn; var. _c_a_rniolic_u_m_ Luetk. ihbreviatjgr; Racib. ghbreviagg; var. Bil—1.93 West. subcapitulfl West. Sphagnicolum West and West fa. refringens Taylor. m_o_erlian_u_m_ var. brasiliense Borge fa. difficile Luetk. abbreviatgg; var. planctonicum West and WBSto Reggellii var. minimum Eichl. and Gutw. quadratul_m_r; var. applanatum Insam and Krieger. Regnesii var. tritum West. gufadratulg; (Gay) De Toni. E5913 var. getangularlg (Wille) West and West. clepsydra Nordst. monomazum var. Bolmazum Nordst. excavatum var. duplo-major Lund. Witttrockii var. quasidepressg; $101330 ordinatum (Boerg.) West and West. m .17 (Don eon) n J 0') gteou ‘00 OD UV Plate 18 1° W W var. simplicius West and West. 2. _C_. annulatum var. elegans Nordst. 3. 9. Netzerianum Schmidle fa. o e hroideum Wittr. 1+. 9_. p rtianum var. n p 5. 9_. Pieudoornatum 216111. and Gutw. 6. g. taxichondrum var. Irenee-Marie nob. 7. 9_. taxichondrum var. obsoletumifogng var. 5131. 8. 9. tagciohondruy; var. nudmn Turner. 9. Q. protracgg; var. basigranulatum var. nov. 10. 9. pseudotaxichondrum var. Foggii Taylor fa. 11. 9_. amoenum var. mediolaeve Nordst. P1. 13 ‘1 1. 2. 3. u. S. 6. 7. 8. Plate 19 Cosmarium subbroomei Schmidle fa. West and West. E. amoenum Breb. zygospore. E. commissurale var. crassum Nordst. E. biretum var. minus Hansgirg. Q. binum Nordst . Q. sexnotatum var. tristriatum (Luetkm.) Schmidle. E. novegicum Strom. .9. margaritatum var. ridibundum Taylor. 18 \\ Sedhhbbxo 669933) one? 3) ® 99 n o no 666% no eeeu 09 © @QU noeoeeu CC 00 PMCCQO (CCrOCrmCC C C C Plate 20 1. Cosmarium margaritatum var. minor (Boldt) West and West. 2. g. ochthode var. navae-terrae Taylor nob. 3. _C_. gayanum var. eborascense G. W. West. 11.. _C_. Bot tis var. subtumidum fa. Irenee-Marie nob. P1. 20 ....5 “kW _' q Plate 21 1. _C_. guadrum var. sublatum (Nordst.) West and West. 2. _g. Botrytis var. tumidum fa. nudum fa. nov. 1. 2. 3. 1+. S. 6. 7. 8. 9. 10. 11. Plate 22 Staurastrum brevispinum Breb. E. brevispinum var. Boldtii Lagerheim. §_. brevispinum var. retusum (West and West) Borge. E. orbiculare Ralfs . [(0 o orbiculare var. extensum Nordst. [CD 0 orbiculare var. Ralfsii West and West. [M e subpygmaeum‘West. IUJ . Clepsydra Nordst. fa. I02 0 pseudopachyrynchum‘Wolle. It!) 0 Prescottii sp. nov. [02 o Prescottii sp. nov. l. 2. 3. h. 5. Plate 23 Staurastrum grands var. parvum West. E. punctulatum var. pygmaeum (Breb.) West and West. _S_. cuspidatum var. maximum var. nov. §_. connatum var. americanum West and West. IUJ . dejectum var. inflatum West. IUJ . granulosum (Ehrenb.) Ralfs. P1. 23 -_-_. cr‘ 3:8 ~.‘.. l. 2. 3. S. 6. Il——_ Plate 2h Staurastrum guadrangulare var. armatum West. .E. trifidum var. inflexum West and‘Eest. . aviculoides Gronblad fa. ND IM 0 m var. subarcuatum (Wolle) West and West. I0) 0 avicula var. coronulatum var. nov. lm O subcruciatum Cooke and Willis. no.-‘MV-LKC“. .a. " Plate 25 l. Staurastrum subcruciatum Cooke and Willis fa. 2. E. subdenticulatum Nordst. fa. 3. E. setigerum Cleve. P1. 25 mt ..- ,‘V‘I.~ I Plate 26 l. Staurastrum setigerum var. brevispinum G. M. Smith. 2. E. setigerum var. Lectinatum West and West. 3. E. gpiculiferum G. M. Smith. L1. E. muricatum Breb. 5. E. Bohlinianum Schmidle fa. P1. 26 1. 2. 3. u. Plate 27 Staurastrum pilosum (Naeg.) Archer. E. Spongiosum var. perbifidum fa. spinosa Dense-Marie. E. cornutum fa. reductum fa. nov. E. brachiatum var. major var. nov. 21. 2'7 r V- ~m..—'71 sf“. ‘ 1. 2. 3. L1. 5. Plate 28 Staurastrum grallatorium Nordst. _s_. §_. 9. WJ IUJ O grallatorium var. forcipigerum Lagerh. natator West. controversum Breb. affine West and West fa. suEgracilimum‘West and West. 1. 2. 3. 1+. S. 6. 7. Plate 29 Staurastrum anchora West and West. 'E. crenulatum var. britannicum.Messikommer. E. protectum var. planctonicum G. M. Smith. ‘E. Johnsonii var. depauperatum G. M. Smith. E. Sebaldii var. ornatum Nordst. .E. proboscideum var. ornatum var. nov. E. rugosum Irenee-Marie. PI. 20 2. 3. LL. 5. Plate 30 Staurastrum anatinum var. truncatum.West. E. guebecense var. ornatum var. nov. IUJ . boreale West and.West. IUJ . gracile var. coronatum Boldt. IUJ . vestitum var. semivestitum fa. 30 PI . C ,- xi < 1. 2. 3. 1+. 5. Plate 31 Staurastrum floriferum West and West. E. gyrans Johnson. E. distentum var. Michiganensis var. nov. E. distentum var. Michiganensis var. nov. E. furcatum var. pisciforme Turner. 31 Pl. 1. Plate 32 Staurastrum ankyroides var. pentacladum 6.1L autm PI. 32 r a Gfifnn J ) s l .. ’ ‘ , . ’ ’ C J 7 .v .9 9 A 9 J I . _ .... 11 «A a fi .v x a u t to o c o .I IIIII I... a a . c v a c .. c . ¢ 3?) ) . -w-r' “1.34.1. TM-‘« ' 11 l. 2. 3. Plate 33 Staurastrum forficulatum var. cornutiforme var. nov. E. W var. pseudoPisciforme fa. Irenee-Mgiq nob. E. gemelliparum Nordst . E. tohOpekaligense var. breviSpinum G. M. Smith. P1. 33 l. 2. 3. Plate 3k Staurastrum furcatum var. Taylorii var. nov. E. furcatum fa. sBinosa Gronblad. E. bicoronatum Johnson. 1. 2. 3. "LR Plate 35 Desmidium occidentale West and'West. ...—L 1— A wf-w — - 4 Hyalotheca dissiliens var. tatrica Racib. Sphaerozosma exiggum Turner. ‘ ...- Onychonema laeve var. latum West and West. 1 x -—_"."‘.K;' n.---' MtCHIGAN STAYE UNIVERSH’Y LIBRARIES 7W ”3' 1|! 7H; ‘1 1 7“ 7 93 03177 “M“ M : 50 ‘ 7 l1 1+ 79