1:. K ,H J. F D. 30¢. .y'u. § that? {£37.29 _. 3‘ W, .1... ziu‘m .\ - .v ‘ F ~' [1‘1Ku3‘ . L H, ‘ . " Kit, a} “. ' k A ‘f ‘ (a ‘ ': fifilfifigécfi 4 . 3w} firi‘a“ ‘ * , :- {P'aufifl’fhg‘f} 4 3% 31.1“. » . 4, o - dump»; L . 1—4452 "3 ~ w awn?" {a . *0“ it) I, I j ‘ 1‘ {i‘ g», $33.: W1- 3 lat. "x as... ‘ " '.‘,“- ii “137‘ .. . *ggléqé-E‘x. '3:- “Aug? V I, ‘ \ {u “.1 ~ .wt\._ 3:. "1.. “31‘ " ‘\ wb“ ‘ - ’15:?“ ”I 7 . v v i g .vv-f\"£f,u‘ I“ ~ 1:!- 1. ?:l“\;« nv:_ '7‘1’“"'.3- m ,7, a . u, “n.1,; up. .I---== o I I W *1 tan we be!) we mu Bose Apex Figure 21. Unlobed lamina/total lamina (u/t), length/width (l/w), and distance to sinus/distance to midrib (s/m) ratios for leaves from a Type II (no inflorescence) shoot (same as Figure 20) of g. thbrida. 65 fifimuuuum 8 Mmmuofkdh u¢1 um: has nae um: flue Aux Figure 22. Number of teeth on leaves from a Type II (no inflorescence) shoot (same as Figure 20) of P. Xh brida. "Typical" teeth are those representing extenSions of the leaf lamina while papillate teeth represent minute projections without accompanying lamina. 13. -d—VuMb * +e/mreflo +33]an .03 I 0“ '31 T T r U j [‘91 £0.12 MS LMG M5 Lad. fine Max Figure 23. Unlobed lamina/total lamina (u/t), length/width (l/w), and distance to sinus/distance to midrib (s/m) ratios for leaves from a stump sprout of g. thbrida(?). 66 shoots: the first three to five leaves had very few teeth, then the number of teeth suddenly increased by three-fold. This increase is primarily due to papillate teeth fed by tertiary or quaternary veins. Tooth size of Type I leaves varies as greatly as in inflorescence shoots although the greatest number of large teeth (those fed by craspedodromous secondaries) only occurs in the distal half of the shoot. Late season leaves have very few secondary veins that do not directly enter teeth. The angles of the apices do not show a clear pattern, but increase in one case and appear erratic in another (Figure 16). Basal angles, however, do show a conspicuous increase as the beta pectinals increase in strength and angle of departure, and the lamina base grows increasingly reflexed (Figures 17). The l/w ratios of one long shoot initially decrease and then show little change (Figure 19). The l/w ratios of the shorter shoot show a gradual decline which is consistent with that found in inflorescence shoots (Figure 18). The s/m ratios increase in both Type I shoots examined and the u/t ratios decrease (Figures 18 and 19). This indicates a deepening of the lateral lobe sinuses in successive leaves. Type II shoots begin with narrower leaves (higher l/w ratios) than the other canopy shoots (Figure 21). Lateral lobes become pronounced by the third leaf and continue to broaden through the sequence in the usual manner. Similarly to leaves of stump sprouts, the teeth do not follow the customary pattern of increasing in number, but 67 all the leaves have high numbers of teeth (Figure 22). Additional crown shoots need to be collected to assess whether or not trends in tooth number of these leaves exist. Most of the secondary veins in all of the leaves end in teeth, in distinction to the early leaves of typical canopy foliage. Another distinctive feature of Type II leaves, but characteristic of stump sprouts, is the presence of the minute papillate teeth on all of the leaves, including the first two. The lamina base of the first leaf is not truncate, but sharply angled at nearly 90 degrees. By the fourth or fifth leaf the angle broadens to 180 degrees or more (Figure 20). Apical angles decrease slightly through the series (Figure 20). Length/width ratios decrease through successive leaves; s/m ratios slightly increase; and u/t ratios slightly decrease (Figure 21). These ratios indicate that the leaves become broader and the lateral lobe sinuses become deeper although the sinuses are still not as deep as in Type I leaves or inflorescence shoot leaves. The foliage most physiognomically distinct from typical crown foliage is that produced as stump sprouts or sprouts from the base of a standing tree. These leaves differ from crown shoots in both gross morphology and the organization of vein architecture. Three sprouts were collected from one stump of unknown age in a parking lot on the campus of Michigan State University. It is not known Whether this stump is 12- mm or 2.. W 68 because the standing tree was not observed. The largest stump sprout does not have the same pattern of progressively increasing lamina area, perimeter, and tooth number as canopy foliage (Figure 24). The lamina area is initially large and decreases through the series (Figure 25). It should be noted that at least the terminal two leaves probably did not complete their expansion so that the ultimate area of these laminae is not known. The number of teeth found on the leaves roughly follows an opposite pattern to that of inflorescence leaves: tooth number is initially high (44) in the first leaf, jumps to 82 and 84 teeth in the second and third leaves, then diminishes (Figure 28). Most of the larger teeth in the first two leaves are broad, but become progressively attenuated through the series. High numbers of small, papillate teeth occur in the early leaves, particularly the first two, but diminish in number in later leaves. Again, this is contrary to the architectural development of Type I and inflorescence leaves. Perimeter measurements reflect the increase in tooth number and size (Figure 27). In conjunction with the narrowing of the teeth, the apical angles also narrow through the series (Figure 26). The base of the lamina is decurrent in all of the stump sprout leaves examined. The first leaves of the largest sprout have an obtuse base; succeeding leaves have progressively broader leaf bases, including the recurved aspect of canopy leaves (Figure 26). Petioles of the first leaves are short and stout, and the lower portion of the primary vein is 69 to pe 8e ma much more robust than in canopy leaves. The lower primary vein and petioles show conspicuous vertical striations in pressed specimens. Sprout leaves have large laminae that do not have deep lateral lobe sinuses. In an extreme case, one long narrow leaf has no lateral lobes. Vein architecture becomes more organized through successive leaves of the stump sprouts. Both secondary and tertiary veins are much less symmetrically organized in the initial two or three leaves than in later leaves. Many of the tertiary veins in the first leaf are reticulate and forked percurrent, but become progressively ordered until the :majority‘ are ‘truly percurrent. Intersecondary and composite intersecondary veins, which add to the dissymmetry of early leaves, are less frequent in later leaves. Normally, in Blatanug xnybriga the lowermost strong lateral veins can be unambiguously labeled as alpha pectinal veins. But the first leaf of a stump sprout can have additionally strengthened lateral veins so that the pectinal terminology is difficult to apply. Furthermore, the pectinal terminology is also often difficult to apply to the abmedial secondary veins (that is, to designate beta pectinals) because several of them may be strengthened. Beta pectinal veins can diverge from the alpha pectinals at many points, and only one side of the lamina may have a beta pectinal vein. Inferior secondary veins are relatively well developed because of the suprabasal departure of the alpha pectinal veins and the decurrent 70 Figure 24. Leaves from a stump sprout (same shoot as Figure 23) of B. thbrida(?) numbered from the most basal leaf in the sequence. 71 Figure 24 72 g 4 Lamina one (mm ) § 7///////// 5W SJ////////2 3- M E/ M— bell Apex g4 80 Figure 25. Leaf lamina area for successive leaves from a stump sprout (same shoot as Figure 23) of E. thbrida(?). 35¢. -0-beeelnele 200* 150-1 g 4 2 5' 1w- ”-1 o f I —T I fi W1 Led! Led) LedG W5 lad. Bose Apex Figure 26. Leaf lamina apical and basal angles for successive leaves from a stump sprout (same shoot as Figure 23) of g. thbrida(?). 73 10101 . d O C d o *////////////////////// EJ”////////////// \ m- ust: we Bose Apex 710 §~////////////////% 3% 3/////2 Figure 27. Leaf lamina perimeter length for successive leaves from a stump sprout (same shoot as Figure 23) of g. thbrida(?). arena-um .“Wbeth ”a: i s"- : x o 3 lx-‘i , E a 2nd .1 teen teen Leda Lee” has Lute Bose Apex Figure 28. Number of teeth for successive leaves from a stump sprout (same shoot as Figure 23) of E. thbrida(?). "Typical" teeth are those representing extensions of the leaf lamina while papillate teeth represent minute projections without accompanying lamina. 74 .7 : $5 \\\\\\\\\\\\\\\\\\\\\\\\\\xww .4e.e.e.e.e.e.e.e.e.e.e.e 9.. I .weweeeeeeeeeeeueeeeeeeeeeee. oee e.e.e.e.e.e.e.e.e.e.e.e.e.e e.. eweeemeweeeweweeeweeeeeeeweeeeeeeeee. OOOOWOOOVOOOOOWOMOOOO. O O O O O O O O 0 0.0000000. 0000000000.». 00000 e.e.. .e.e e ee e. w w ‘ 0.06.0.06...’ O...0.0.0.0.0.0.0.0.0 0.0.0... 000 0.0 00. 000.000.... eeeeeeee . .o. .o. .o. . . . . . . . . .ewowomowomom a§§§§8§8§§§§€§8§x m 0,9...06 OM0...’ 0.. 2 COO eeeeeeeeeee.eee e e.. .‘e.e.e.e,e.. .3. 000 eoe. N‘ ‘ A q ‘ E (1 .5 60.3 2..qu w CI w Leaf lamina area of successive from two non-inflorescence shoots (shoots 6 and 7) of Platanus occidentalis. leaves 29. Figure — 7 .\\\\\\\\\\\\\\\\\\\\\\\xw meeeeeeemeweeemeeeeeeeeeeeeeeee. C 0.0.0.0000 9 ..e.e.e.e.e.e.e.e.e.e.e.e.e.e .eeweweweweweweueweeeeeweeewemeweeee. oe.e.e.e.e.e.e.e.e.e.e.e.e.e.e.e.. 3 e eeeeeeeeeeeeeeeeweweeeeeeeeeeee. v. . . ...)...e...h.'.0.§.0.v.e ..e.e.e.e.e.e.e.e.e.e.e.e.o e.e.e e.e.. 5 .e.e.e e... e e e e eeeweuewewewewewew. . w -96.... 4 0.0.0.0...0.... . . Kx£.: O 11001 4 d ‘ AEEV c8253.. 0553 w perimeter Leaf lamina Figure of length 30. successive leaves from two non-inflorescence shoots (shoots 6 and 7) of P. occidentalis. 75 cond: )eav have sUn TYP' lot tee Pa; at! spi Fol of ad a1 ca se has $12 Len .735 Ovat from condition of the lamina. Additional shoots which consisted of only two to four leaves were collected from the lower inner crown. These have an obtuse leaf base (some are decurrent) similar to stump sprout and Type II leaves, and the large teeth of Type I and inflorescence leaves. Well developed lateral lobes without deeply incised sinuses are present. The teeth are almost entirely of the large type; small, papillate teeth are usually not present. The teeth are attenuated, and the apices are unique in having long, spinose tips. Foliar characteristics of Elatanus gggifientalis L. The following description is based upon a collection of 17 leaves (three shoots) from one tree, none of which were from an inflorescence-bearing shoot. Twelve additional leaves were measured from herbarium specimens. The leaves of this plane tree are usually three-lobed although early sucker leaves and leaves with large teeth can have less defined or weaker lobes. The earliest seasonal leaves often lack lateral lobes even though strong basal secondary veins feed large teeth which approach the size of lobes and provide a triangular aspect to the leaf. Length/width ratios for canopy (non-sucker) leaves averages .735 (range .76 to 1.24; n= 36). Newly sprouted trees have ovate to obovate leaves. The texture of the leaves ranges from chartaceous to coriaceous and from glabrous to 76 der 9;; deg lot lor the 16 mum is larg Part The 82 “hid densely pubescent on either surface. Typical 2. W5 leaves have a more squarish outline than B. XDXDIida, that is, the base of the lamina is closer to 180 degrees and is nearly as broad as the laminar width between lobe apices. The apices of the lobes range from acute to long and attenuated. The average angle of divergence for the apex of the central lobe is about 31.7 degrees (range 16 to 62; n= 26). sinuses between the lobes are rounded and shallower than 2. XM or 2. 9113113115. The average angle of divergence between the central and lateral lobes is 116 degrees (range 98 to 149; SE= 1.92; n= 33). The bases of the leaves range from recurved to truncate to obtuse, except in sprout leaves which have acutely tapering bases. The lamina often extends down the petiole in either a decurrent fashion, such as is common in sucker leaves, or in a more obtuse extension, such as is common in typical late season leaves. The mean angle of divergence for the leaf bases is 223.5 degrees (range 122 to 310; n= 29). A. great. deal of 'variation. occurs in ‘the size and number of the teeth. The average number of teeth per leaf is 30.3 (range 7 to 71; n= 28). Some leaves have very large teeth which approach the aspect of incipient lobes, particularly those which are fed by the alpha pectinals. The smallest teeth are simply papillate projections formed by veins which extend beyond the margin of the lamina. Shapes of the teeth conform to Hickey's (1979) types B1, B2, C1, and C2, and usually terminate in a spinose tip which may be quite long. Several tooth types may appear on 77 one type tee1 Peti typj strc and curx base 0.7 secc 0f ; SUPE euca Abme at a Thei SeCo: Sinu5 Super one leaf and all of the teeth except the minute papillate type are typical platanoid teeth. The sinuses between the teeth (excluding the papillate type) are scalloped. Petioles have a swollen base covering the axillary buds typical of subgenus Elatgnus. The venation of later seasonal leaves is either strongly actinodromous or palinactinodromous. The midrib and alpha pectinal veins are stout and straight to weakly curved. The alpha pectinals diverge from the midrib either basally or suprabasally at a distance ranging from 0.0 to 0.7 cm (mean= .12cm; SE: .033; n= 32) from the lamina base and at an average angle of 52.8 degrees (range 36 to 70; n= 57). The first leaves of the season are pinnately veined and lack alpha pectinals. By the second or third leaf of the shoot beta pectinal veins have developed and diverge off of the alpha pectinals at distance ranging from 0.6 to 1.6 cm from the alpha pectinal--midvein juncture. Superior secondary veins arise from the midrib at an average angle of about 54.4 degrees (range 45 to 72; n= 60). The superior secondaries can 1x2 either craspedodromous, eucamptodromous, brochidodromous, or’ semicraspedodromous. Abmedial secondary veins diverge from the alpha pectinals at an average angle of 56 degrees (range 33 to 77; n= 36). Their marginal course is like that of the superior secondaries. The secondary veins which approach the lobe sinuses may branch and form connecting loops to both the superjacent superior secondary and the admedial secondary 78 veins. Inferior secondary veins are weak and may either terminate in teeth or form brochidodromous loops. They' occur in suprabasally actinodromous leaves, especially where the lamina extends down the petiole. Intersecondary veins are infrequent and most often occur between the alpha pectinals and superior secondaries, or in the upper third of the lamina, or as abmedial veins. Both simple and composite types of intersecondaries are common. As in most Elatanus leaves the tertiary veins vary from strongly percurrent to forked-percurrent to reticulate. Chevrons are formed by the tertiaries in the axils of the primary veins, and the axils of the secondary and primary veins. Tertiary veins can join admedial secondary veins and thereby also form Chevrons proximal to the lobe sinuses. Tertiaries are orthogonal (average angle of divergence is 84.2 degrees, range 69 to 96; n= 102) and consequently those associated with the abmedial secondaries are longitudinally oriented with respect to the midrib, and those associated with the superior secondaries are obliquely oriented. Tertiary veins are spaced an average of 0.3 cm (range 0.1 to 0.5 cm; SE= .0126; n= 54). The quaternary veins are normal in thickness and approximately orthogonal. Quinternary veins form the areoles and vary from random to orthogonal in course. Well-developed areolation is quadrangular or polygonal in shape. The marginal ultimate venation is looped. 79 Foliar heteromorphism in Elatanus occidentalis Significant and repetitive trends in the physiognomy of successive leaves on the shoots of Blatanus occidentalis were found. Recurring patterns in the leaves were exhibited by both gross morphological and architectural features. The leaves of this species which were examined in greatest detail were from sterile crown shoots. When inflorescences occur, they terminate a shoot; continued apical growth beyond the inflorescence does not occur as it does in 13. KM. Stump sprouts were not included in this study. The overall change in gross leaf shape between the earliest leaves and the latest leaves is quite pronounced. The first three or four leaves have the squarish aspect seen in the pre-inflorescence leaves of L M11513: the outer margins of the lobes are roughly perpendicular to the base, and the alpha pectinal veins are nearly perpendicular to the midvein. Change from this morphology is easily followed by noting the increase in the basal angles of the laminae which proceeds throughout the growing season. Initially, the lamina bases are broadly obtuse or truncated, but each succeeding leaf developes a more reflexed base (Figure 32). That is, the beta pectinal veins grow stronger, become acute with respect to the petiole, and develop strong abmedial secondary veins. The apical angles of the laminae did not follow the clear pattern of 2. XM. Figure 31 shows that the apical angles increase along one shoot studied, while another 80 shoot did not show any clear pattern. Additional sampling is needed to determine whether the increase in apical angles of the distally successive leaves is consistently present or not. A leaf form has been observed from several trees in which the lamina forms a semi-peltate condition where narrow finger-like extensions of the lamina occur at the petiole-lamina. juncture. Schwarzwalder (1986) indicated that this condition is caused by the sycamore anthracnose (gnomonia veneta), a pyrenomycete. However, such an explanation may be questionable as Agrios (1988) states that this pathogen causes shoot blight and leaf blight, resulting' in symptoms that are completely unlike these lamina extensions which occur on otherwise healthy leaves. These laminar basal extensions are quite simiar to some found in fossil platanoid leaves (Ward 1888, 1890). Lamina size was found to increase through successive leaves, but the seasonal peak in size among different shoots did not necessarily occur at the same node (Figure 29). Leaves from later in the season are progressively smaller. The l/w ratios showed a slight trend toward increasing, that is, a proportionate increase in lamina length through successive leaves and the u/t ratios decreased through successive leaves, indicating a deepening of the lateral lobe sinuses (Figures 33 and 34). The number of teeth can increase at least five-fold (Figures 35 and 36), and high numbers of teeth can occur by the third 81 -+-.aeet0 ”q + M7 ‘0: 3 ;§”d _4////,\\\\5 3 ...1 ~33 10‘ o I 1 V T'— I 1 W1 M2 W3 W6 mu L001. L001? Bose Apex Figure 31. Leaf lamina apical angles of successive leaves from two non-inflorescence shoots (shoots 6 and 7) of E. occidentalis. 350- *M' +830“? "3004 '3’ u e 1; V 0 22501 § 820m 160 r 1 W1 Lest! Lee!) “(94 we: Led. Figure 32. Leaf lamina basal angles of successive leaves from two non—inflorescence shoots (shoots 6 and 7) of g. occidentalis. 82 1" *Ihm ! i Figure 33. Unlobed lamina/total lamina (u/t), length/width (l/w), and distance to sinus/distance to midrib (s/m) ratios for leaves from a non- inflorescence shoot (shoot 6) of E. occidentalis. 11 +Ihm0 a~ h“~\‘k\\ .H o I I r I 1 “I M! “It! I.“ we WI flue Max Figure 34. Unlobed lamina/total lamina (u/t), length/width (l/w), and distance to sinus/distance to midrib (s/m) ratios for leaves from a non- inflorescence shoot (shoot 7) of g. occidentalis. 83 'Ww Number of teeth be“ Lean Lest: we we me new Base Apex Figure 35. Number of teeth of successive leaves from a non-inflorescence shoot (shoot 6) of P. occidentalis. "Typical" teeth are those representing extensions of the leaf lamina while papillate teeth represent minute projections without accompanying lamina. arauca-m fiSmuuwmm Number of teeth 8 Wt W2 M3 we ”5 Last. Bose Apex Figure 36. Number of teeth of successive leaves from a non-inflorescence shoot (shoot 7) of P. occidentalis. "Typical" teeth are those representing extensions of the leaf lamina while papillate teeth represent minute projections without accompanying lamina. 84 85 leaf (in contrast to the inflorescence shoots of E. thpriga). Tooth size also varies greatly although an abundance 360 degrees), and in the decurrent or loosely peltate condition found in some canopy leaves and most sucker shoot leaves. of .some species. Other taxa which superficially resemble jplatanaceous leaves, such as the Vitaceae and yibnxncm, can be eliminated by their foliar regularity and lack of decurrent or peltate lamina bases. As Ward (1888, 1890) observed, the presence of narrow basilar projections of the lamina around the petiole is also an indication of this family. Schwarzwalder and Dilcher (in press) refer to the lamina bases of W, gradnczia, W and stump sprouts of m ccciccncalia as being perfoliate. However, I question whether this term is appropriate. Perfoliate refers to leaves which are sessile and have the stem passing through them. This morphology would be highly unusual for the Platanaceae. I have never seen a stump sprout of P. ccciacntalis, E. thczida, or B. raccmcaa with this morphology, nor have any figured platanoids that I have seen convincingly show this condition. Those figured fossil platanoids with apparent peltate lamina bases and no visible petiole may simply have the petiole curving downward into underlying sediments. 137 Schwarzwalder and Dilcher (in press) report that the multidimensional scaling' and.lcluster' analysis tended 'to separate leaves *with. a jperfoliate (peltate?) base into distinct groups based upon other morphological characters. As they note, this would be expected based upon the present state of Placanac variability. Tooth architecture is usually of the pflatanoid type, but this feature too, is not consistent throughout the family. Elacanac kczzii has unique marginal venation which includes unusual tooth architecture consisting of vascularization by branches of an inner marginal vein, and bracing on either side by an outer marginal vein (Schwarzwalder and Dilcher, in press). Wing (1981) also found Placaaaa gcillclmac from the Eocene to have violoid teeth. The presence of extensive heteromorphism also suggests significant applications in the systematics of fossil species already identified as belonging to the Platanaceae. Workers with platanoid leaves should strongly consider the potential that their suites of variable leaves represent heterophyllic shoots, including sucker shoots, derived from a single taxon (or even a single individual). Characteristics such as, the presence or absence of alpha and beta pectinal veins, highly ordered versus dissymmetrical venation, lobe number, tooth number and size, angles between lobes, and shape of the lamina base, have all been used to distinguish fossil form-species, but all of these can be highly variable within even a single 138 modern species. The possibility that different fossil Platanus species represent adult and sapling foliage of a single species has been suggested by Wing ( 1981) for two sets of taxa. He suggested that film W may be the sapling foliage of E. hm which occurs in the same locality because 2. gaillclmac has characteristics similar to those of the sapling foliage of P_. W- He also suggests that B. mnclcaii and B. 112111.113. may have a similar relationship. Fossil leaf taxa that fall into the general category of the platanoids have been consistently confused with taxa morphologically and architecturally similar to the Platanaceae. Several points can be made here concerning some of the families and genera that are easily mistaken for unlobed platanaceous leaves. The following observations are not based upon complete surveys of the families and genera in question, but they are valid for at least portions of these groups. The Vitaceae, 111mm, and the Menispermaceae are some of the most potentially difficult taxa, especially the unlobed forms. All three of these taxa have members with actinodromous primary venation and percurrent tertiary veins (which also often form chevrons in the axils of primary and secondary veins). These features are conspicuous and shared with the Platanaceae (subgenus Platanus) so that they have frequently been a source of 139 misidentifications. However, none of these taxa has platanoid teeth. The majority of the Vicia herbarium material which I examined commonly has teeth that conform to Hickey's (1979) types A1 (convex-convex) and B2 (straight-straight). These tooth types are uncommon in Blatanaa. Some Viburnum species do have dimorphic foliage (unlobed and three-lobed leaves) as well as primary, secondary, and tertiary venation similar to 21m, but lack platanoid teeth. Some members of the Menispermaceae are similar to Biacaaca; Maniapccmam canaacncc even bears unlobed, three-lobed and five-lobed leaves. In addition, Ruffle (1968) considers the Cretaceous chdnczia cancificiia to be menispermaceous rather than platanaceous on the basis of gross leaf morphology. He also states that the cuticle of this fossil bears some similarities to the Menispermaceae. waevery Hollick. (1930), Brown (1962), Depape and Brice (1966), Kutuzkina (1974), and Schwarzwalder and Dilcher (in press) all regard gzcdncnia as belonging to the Platanaceae. Wolfe (1977) indicates that the Menispermaceae can be identified by the presence of :marginal (fimbrial) veins, and. irregularly' branching intercostal tertiaries. Finally, none of 'the representatives of the above taxa that I have examined possess the heteromorphic variability found in subgenus Elacanas: the variability in secondary venation, tooth size and number, and particularly the lamina base. Large suites of fossil platanaceous leaves would be expected to demonstrate considerable heteromorphism (unless, of course, 140 the fossil taxon is more similar to extant subgenus cacganccphyiicm which has simple, unlobed leaves). The status of Cretaceous platanoids The identification of angiosperm leaf megafossils in the Cretaceous, as well as other time periods, is impeded by several difficult problems. Two of the problems are especially significant if the goal of the inquiry is the reconstruction of "whole plants" from the fossils. The first problem concerns the high degree of intraspecific foliar variability in modern taxa and the recognition of such variability in fossil taxa. Foliar heteromorphism is present in varying degrees in many woody taxa, and some, such as the extant Elacamis examined in this study, and Acacia, are remarkably heteromorphic. Others, such as Cercidiphyllum, members of the Aceraceae, and Ginkgc, are at least dimorphic if not polymorphic. If pronounced intraspecific variability is present in extant taxa, the possibility of similar variability in related fossil taxa must be considered. Among the fossil angiosperms, Cretaceous and Paleogene platanoids and trochodendroids are notorious for forming what are often called "complexes" where the intergradation of leaf morphologies obscures taxonomic boundaries. This intergradation of leaves in the fossil record could have several sources. Spicer ( 1986) suggests that Cretaceous leaf fossils may be exhibiting extensive morphological 141 intergradation because of evolutionary radiation, overlapping population samples, hybridization, polyploidy, or phenotypic plasticity. Surprisingly, he devotes the least consideration to plasticity when, in fact, the Cretaceous platanoid leaves which form a significant part of his data base, are today represented by Eiacanac which exhibits tremendous foliar plasticity. How can questions concerning hybridization, polyploidy, and evolutionary radiations be addressed prior to thorough considerations of heteromorphic variability in the highly plastic modern equivalents? The second problem is the practical side of the first: How are the leaves and leaf fragments of taxa with suspected high intraspecific variability to be identified and named? If the leaves of a modern Elaianac Xhmrida were preserved in a sedimentary basin, what could the "fossil" record look like? First, it should be emphasized that sucker shoot leaves would be expected to constitute a very small percentage of the total Eiaganua thbzida leaves in a deposit. But at least leaves from four shoot types, each of which bears a somewhat distinct heterophyllic pattern, could potentially be found. It is probable that when the entire melange of leaves was sorted out, four or even five (due to the "reset" phenomenon) distinct heterophyllic sequences might be recognized. In addition, because of the rarity of sucker shoot leaves and the inevitable gaps in the morphological transitional series among leaves and shoot types, the situation that would 142 emerge is a "complex" of leaves showing much intergradation, but also apparent morphogical discontinuities. To what extent should individual taxa be segregated from this assemblage of leaves? This is a difficult question and it has been approached from both "splitting" and "lumping" perspectives. Many of the older workers such as Lesquereux (e.g. 1892) and Hollick (1930) opted for a high degree of taxonomic "splitting". Hollick (1930) named new fossil Elaiamic species which, on morphological criteria, could certainly have come from the same tree. He also named new platanoid genera (e.g. Eacudcprctcphylicm and Pccadcaspicicpnyiiam) on the basis of relatively minor differences. Some modern approaches to dealing with fossil leaves showing high variability and intergradation of morphologies have sought a more realistic method for identifying and naming the fossils. One approach is that of Spicer (1986) who suggests a preliminary taxonomic framework for Cretaceous leaves which groups specimens into forms that are broad morphological categories prior to assignment to formal names. The utility of this approach is that it seeks a larger data base to accomodate the variability of populations of leaves and thereby hopefully avoid excessive taxonomic revisions necessitated by premature conclusions. However, these same goals are inherent in the traditional form species and genus concepts. A careful approach to the 143 naming of Cretaceous angiosperms using form species and genus names attendant upon a critical assessment of the variability of suites of both fossil and modern leaves would accomplish the same goals. Eleven different forms were used by Spicer (1986) to accomodate Alaskan Cretaceous leaves. Most of these categories are subdivisions of, or equivalent to, Krassilov’s (1977) earlier foliar morphological types. The recent quantitative approach of Schwarzwalder and Dilcher (in press) is another attempt to delimit Cretaceous fossil leaf taxa in light of foliar variability. They conducted a phenetic analysis of Cenomanian Platanaceae utilizing cluster analysis and multidimensional scaling, and erected or emended thirty-two species in five genera using methods which utilized all of the available data, deemphasized morphologically plastic characters, eliminated or minimized overlap between taxa, and were broadly defined for ease in identification. Mid-Cretaceous and Upper Cretaceous angiosperm leaf fossils have been grouped under informal descriptive names by Crabtree (1987) in a manner like that of Spicer (1986) and Krassilov (1977). Crabtree's categorization of platanoid leaves is worth reporting here because of its bearing on the Blackhawk platanoids. Three morphotypes of what can be loosely called platanoid leaves were distinguished by Crabtree from mid-Cretaceous floras of western North America. The pentalobaphyll leaf type is characterized by 144 Crabtree as having 3-5 lobes, palinactinodromous primary venation with a suprabasal departure, eucamptodromous, weakly developed secondary veins, reticulate to transverse tertiary veins, an entire margin, and a more or less cuneate base. He indicates that although Doyle and Hickey (1976) include Azaiiacphyiiam thuailgbum in their platanoid line, he believes that it falls within a nonplatanaceous pentalobaphyll type because of the entire margins, eucamptodromous secondaries, weak tertiary venation, and absence of orthogonally branching tertiary and quaternary veins. Crabtree does not believe that palmate lobing and palinactinodromous venation are alone sufficient to regard a leaf as pdatanoid, especially when they are accompanied by other "nonplatanaceous" morphological characteristics (as in Azaiiacphyiinm cbcaaiicbam). Other examples of the pentalobaphylls bear a lauralean affinity as suggested by cuticle morphology, sinus bracing, mesophyll secretory' glands, and. possible basilaminar secondary veins. A rosid affinity is also apparently suggested by the secondary and tertiary venation of this leaf type. The second leaf type is termed the platanophylls because of their obvious similarity to subgenus Platanus. These are characterized by lobed or unlobed leaves, entire or serrate margins, palinactinodromous venation with several pectinal secondaries on laterals, and straight secondaries that fork or branch exmedially. Also, the 145 secondaries may be either craspedodromous with teeth, or brochidodromous with an entire margin; tertiaries and quaternaries form an orthogonal network. The teeth are of the platanoid type and have glandular processes that are often papillate. The protophylls are another variation of the platanoid leaf type. The leaves are sometimes lobed, and have entire or dentate margins. Venation is pinnate where the basal secondaries are sometimes strengthened and bear pectinal veins. Secondary and higher order venation is similar to the platanophylls. The protophylls are distinguished by Crabtree from the platanophylls by pinnate venation and a more consistent craspedodromy in the protophylls, and a greater tendency toward lobation in the platanophylls. Similarities between the two groups are well-defined, orthogonl-reticulate, tertiary and quaternary venation and an intergradation of the two morphotypes in "many cases" such that "recognition is difficult." Crabtree proposes that the platanophylls are closer to the platanaceous line of the Hamamelidales than are the protophylls. Neither Spicer (1986), Schwarzwalder and Dilcher (in press), nor Crabtree (1987) comment on the extensive foliar heteromorphism found in extant species of the Platanaceae. While each of these treatments of Cretaceous platanoids is a vast improvement over previous studies which often defined the fossil taxa too narrowly, none of them treat the range of foliar heteromorphism/heterophylly within the modern family. As they currently stand, Spicer’s three 146 platanoid leaf types could all be found in a single individual of Placanaa ccciccncaiia. CIabtree’s distinction between the platanophylls and protophylls on the basis of lobation and secondary vein architecture should be reconsidered in view of high infraspecific variability. And some of the architectural characters measured by Schwarzwalder and Dilcher among different taxa show less variability than within single individuals of modern 21.33311115- This is not to say that their phenetic analysis was too discriminating, but the study could only benefit from a similar phenetic analysis of the foliar heteromorphism in the living taxa. It is possible that a single individual of 21m thhrida would produce distinct clusters in the same phenetic analysis that could be interpreted as different species, if not distinct genera. Affinities of the Blackhawk platanoids Both the question of familial affinity and the question of applying the appropriate form-species name need to be considered for the Cretaceous leaves of this study. Table 1 compares certain morphological characters of the Blackhawk platanoid to the corresponding characters in the leaves of Platanus anda. 2. Walls. P.- iindcniana, and E. naccmcaa. The Blackhawk platanoid fossils do possess structural characters which are normally suggestive of alliance to the Platanaceae. The fossil 147 opossuvoawuoe m.o I am ae—Iena omaII nIOQ— I fliofl n.~ I an noauaa «as.» n.~o I anal a: emu-agenda ago. I um on._Ima._ IuIII n~¢.~ I amen uaouusuov uo vevasou a pwoaauafie seasxuufim usoaauvoawuoa Inwaan .esaflouvoamuua a~.4~ I am anNIoa one.» ecu I anal mm.o I ma ssIn— ewaau o.~¢ I seen ncIm I an ooI~N owaau o.h¢ I anal sao.¢ I an uoIn once» m.cu I aqua euafifimean van vmoaauefia anec. I an Lun.~-xaa. ImaII «mo. I aaoa uaeoaue aspen voeanoI> no .auavuou .oueoaauu manned .aaaubo .auaaasu Ase n I n flmoawuflh ummmmuam «soaauvaamuoa Iamuaa .eaaaouvoamuoe .ouaaame ae.a I ma ¢o_Is__ ImIII cobnu I “‘0' mw.¢ I um oeIcN owaau um I nevi a! NN~.~ u mm omlc awash «.0 I aqua ouadgmnaa van vmaaauafie Nnuc. I um 04."-nc._ Imcqu w~.~ I seas ouauasuu a» menace n I m acoecovcefi ascaua~m oaoaouvoamuue Iceman Insoaauvoamuoa Iouaasme a~.- I am sonINna ouaII nINNN I use! sfio.— I am NeIou amaeu n.0u I sea! «Na._ I um saunas one.“ c- I seal nna.n I am Nels omaau NIeN I can! auau—mnaa use pmoaeue~e a—Hc. I am nea.uoa. one.“ em». I seal uaaone uaauaue ooamuaEOa uawavaoana ~auen "venouuuu cu auauasuulauaua n I a «Hammmwmwmmm oscauemm usaaauuaamuoe Iamuan .esaiauvoamuue .eueaame n4.a I ma canIaa Ina.“ mun I seal mon.~ I am onuo~ emu-u an I seal New.“ I ma anaIec can.» MINo I deal mm¢.n I an NOaIm ouaau QImn I deal ouefiameae can emaueue—n on—c. I an an.—Iaaa. use.“ «no. I deal unaaaua uuoane wean:- am unouuaoev “vexafiueu a» auauaaquooauno n I — evmununx asaeueam ousuueumsuue aawueao> — oamae deuce 0H»:- “comma nona~ Haueueu can ueuuaou avenues eunu- SuOUu HO Hflfiflflfl hmoHoaeuaI cuppa amueu e\~ euaa£a cacao-auauuam am aueuuan :uoeou: uncaosauol veep ocean" acmueaog .s .n .N .uouuo vuapaauo .mm .dmmmmmmw 2M .dddmemmwd mM ..maaua umuo .eanaufifieea no: .:x oaaouafim mo euouoauesu ~aumwo—osauol unm~6u up naemuenIao .m ounce 1118 finaowosuuo unwanuun no megaflobov wanna: mNo.I um a.In. ownnu “one I 80: nI~ I an soulmc I ownnu sIQw I anal ounaaumuou hganaomnnuoo ou uaouusuuoe unonpn usn. I an HUM-OIOIH OMHCH IONIM I BUOB No.— I um mmInn owanu o.sa I anal nsoloupovoennuu snaoaouVOualnuao Nae. I Nu IO&IQIO owfldh a0¢¢e~ I GU“! os.~ I an hmInN omunu NI°¢ I “HUI peonnunun xennxunam anaowoauuo vooo~o>ov ufioa “no. I um Buo.~ImN. ownnu lusun. I anal mam. I mm males uwunu N” I a“. ounfiaowuou cu unannouuan unenoun ae~. I ma fiU‘ofilhoO ONGQH lO—IN I Diva OQI— I an chlnfi umcuu hohn I ”I”. naoa6uvovoannuu naoaouvovoennuu lmflUn naoBOuvovMsooua naoloueoualnuao wad. I mm lum.~Io omen» §Qe I “‘06 c~I~ I am finnsu ownnu o.on I one: GQOEUUQH OSGIHQHK anaowosuuo voeogeeop "Ho: oo.~ I an calms ownnu “emu I “.0: a: ounasumuou cu unannouuoa anemone n: so.~ I am mmImn owcnu m.me I anal nooBOHvovoannuu n:0§buvovonnnuu Imaon n=OBOuvovfinooua naoa6uvouaanu=o a: mm.N I mm OGIOM Owflflh QIOM I G503 manecumama nocnunum ~naowonuuo voeodoaov flan: ouuo. I an lon.I—. ownnu ion. I anal ouwo. I an noIcn umanu QeOQ I fififla ounaaumuou ou uaouuauuon unonoun deco. I um Bun.NIa. omen» lunn.~ I ones «can. I mm «elm: owanu Ocen I 6'03 noosouvopoennuu naoaouvovonnnuu Imam: n5056uvovmsuoun nsoaouvounanuao ammo. I an 508.10 OMGIH EUN-e I ”‘0' a~o.~ I an ouncn owanu ~.an I anal negnuaovmuuo dmmwunfim finaowosuuo voeoaopov "we: uuao. I mm noIlmuI Dwain *MM. I EGO. wnoo. I am NeINo ownnu MIN” I 9‘03 eunaaamuou ou unouuauuoe unnnoue «moo. I an ~.nIs. anon» do.— I anal weao. I flm colon emanu Ned“ I 5C0- naoaoueovoennuu naoIOIvovaennuu Imlen naoaouvovmsooun naoaouvouelnoao name. I am N._Ic anon» ”OM. I “'0' oo.~ I am «clan owanu n.ne I anal nveunmnx nannunmm ouauoouwsoun nowunno> c .uu name? hunlmue mo nmmxn am name» n he voluou enoupuno Ion name» n nooauoa ouanunmv .o— ououuneov no ofimnn nomunno» n .w~ ouauuoumcuun aomunnu> n In" namep hunnaouenuounn .0— nnmo> N newuonan pontoon nuanunmv .m~ canon nuauuneov Anomnoeanv newunnop u .e~ ouauuoumnuun Anomuoeonv nomunlob a .m— nwwmuo unowuoon o» ouauonam ufiowquInnmlna Iona nun-unwv .N~ euman unsouneov mnnmuuoe .~— voanwuaoo ~ ounna 149 leaves are suprabasally actinodromous, and have prominent secondary and tertiary venation. Orthogonal departure angles for the tertiary and quaternary veins, and a tertiary vein course which is predominantly percurrent (but varying to forked percurrent and reticulate) and forms weak chevrons in the axils of primary and secondary veins are also, in concert, distinctly platanaceous. Leaf apices are not well-preserved. However, lamina bases are preserved in a number of leaves and show variability similar to that found in several extant Placanaa species: variability ranges from truncated to slightly rounded, and most significantly, several bases have distinct decurrent extensions. In some instances where the lamina margin is visible and bears small spinose/papillate teeth it is slightly scalloped. All of the above characters are important diagnostic traits of the extant subgenus Biaganac, and therefore represent, albeit incompletely, the family Platanaceae. Some of the structural features of the fossil leaves are different from the modern family. The large unlobed leaves have few secondaries that are quite widely spaced as opposed to much narrower spacing in unlobed leaves of Platanus, maxicana or E. unccniana. The secondary veins commonly bifurcate well before the margin. In extant subgenus Biacangc bifurcations of the secondary veins occur less frequently and closer to the margin of the leaf. One of the most conspicuous differences is that while the secondary veins of the fossils are craspedodromous, they do 150 not end in platanoid teeth, or even teeth that simply include portions of the lamina. The few visible teeth are small spinose/papillate projections of the craspedodromous secondary veins, which are superficially similar to the papillate teeth in Eiacanaa. However, the papillate teeth in extant Bug-Lam are generally vascularized by the semicraspedodromous condition or other marginal tertiary or quaternary veins, whereas the fossil leaves have the secondaries ending at the margin or forming the small teeth. The Blackhawk leaves also lack intersecondary veins which are consistently present, to varying degrees, in the extant mamas species examined. In both of these last features the fossils more closely resemble Accinicia. However, Accinidia lacks orthogonal quaternary venation and decurrent leaf bases. The tertiary venation forms weak chevrons in the axils of primary and secondary veins, but many of these veins are also straight to nearly straight. The fossil taxon most similar to the Blackhawk platanoids that I have seen is czcdnczia. Crabtree (1987) includes cncdncria in his concept of the protophylls which he suggests are more similar to mainline Hamamelidales than are the platanophylls. But Schwarzwalder and Dilcher (in press) who have recently emended czccnczia as a result of their study of Cenomanian platanoids using multidimensional scaling and cluster analysis place it within the family Platanaceae. Included within their revised concept of the genus are some fossil taxa previously assigned to giacitcs, 151 Paulina. W. and Blatanus. as well as the synonymizing of Ercccphyiiam. The Blackhawk platanoids and typical cacancria are similar in having an unlobed lamina, a broad apex (>60 degrees), suprabasally actinodromous primary venation, percurrent to reticulate tertiary veins, and orthogonal quaternary and quinternary veins. The emended description (Schwarzwalder and Dilcher, in press) indicates that the lamina base is variable, sometimes cordate, and ranges from petiolate to slightly perfoliate (peltate?); secondary veins are primarily craspedodromous and diverge from the midvein at angles ranging from >25 to >50 degrees. cream WW (Krasso) Schwarzwalder and Dilcher bears many similarities to the Blackhawk leaves, especially the course and bifurcating nature of the secondary veins. The Blackhawk leaves are always petiolate and some of them have a prominent decurrent extension of the lamina, others have a more rounded base, but none are perfoliate or peltate; the secondary veins are also craspedodromous, but their departure angles range from 31 to 57 degrees (X= 40.2). The secondary veins are also more widely spaced in the Blackhawk leaves. To accommodate the Blackhawk leaves within the generic circumscription of crcdnczia the generic diagnosis would have to be further emended to account for these variations. It is recognized that interpretations of family boundaries become especially difficult when considering the historical roots of a family and the potential extent of 152 the diversity of extinct members of that family. The Platanaceae, whose extensive geological range spans the mid-Cretaceous to the present, is an example of this problem. As described earlier in this paper, the morphological range of the leaves of known fossil Platanaceae exceeds that found in the extant family (subgenus Eiacanaa and subgenus Qaacanccpnyiicm). in: include "atypical" species, that is, those whose morphologial characters diverge from the known extent of variability, in a higher taxon, there should be either additional characters which are shared with the known taxon, or the divergent characters should lay in a transitional series that provides some amount of continuity with the known taxon. In the case of the Blackhawk platanoids, even though some morphological characters are different from the living species, many foliar architectural features of the fossils are found in the extant family so that an alliance with the Platanaceae is compelling. Indeed, when the range of variability of extinct members of the Platanaeae is considered in conjunction with the extant species, a broader concept of the family unfolds which is even more amenable to inclusion of the Blackhawk platanoids. Although the Blackhawk fossils can be placed into the family Platanaceae, they do bear many differences with the extant genus Placanaa, as ennumerated above. In Perker’s (1976) preliminary investigation of the Blackhawk 153 angiosperms he tentatively assigned the platanoid leaves to the genus Placanua. However, this study has shown that it is more appropriate to place these leaf fossils into a form-genus rather than the extant genus. Consideration must also be given to the number of form-species that should be recognized for the Blackhawk fossils. Parker (1976) divided the specimens into two form-species and assigned to them the names RIM raxnoldsii and Eiacanac aiaca. Hollick (1930) erected the name 2. alaca for two figured specimens each of which is only a portion of the basal half of a lamina. The characteristic upon which Hollick based his diagnosis is the presence of a decurrent leaf base. Several other form- species are also placed in the genus Placanna and figured by him in the same monograph. Taken together, some of these form-species show an intergradation of morphology, including leaves intermediate between the decurrent E. aiaca and those with more truncated leaf bases. As already noted, several of these figured specimens are also reminiscent of the leaves of stump sprouts and vigorous crown sprouts. Based upon Hollick’s (1930) figured specimens, I doubt whether 2. 1131;: should remain a distinct form-species. However, the question remains as to whether the Blackhawk platanoid specimens should be segregated into two form species. As with Hollick’s (1930) material, the only significant difference between the two forms is the presence or absence of a decurrent leaf base. Unfortunately, few lamina bases are preserved intact. 154 Those that are preserved do not form a clear transitional sequence between the bluntly decurrent lamina extensions and the truncated to rounded lamina bases. In addition, these extinct members of the Platanaceae may not possess the same type of variability as the extant species. Therefore, although I consider these two forms to constitute a single form-species, I recommend retaining them as two form-species, pending additional collections that demonstrate a greater degree of morphological continuity. THE TROCHODENDROIDS As used here, the term trochodendroids refers to fossil morphotypes with actinodromously or acrodromously veined leaves and entire, serrate, or crenate margins. Some of these fossils are known to be members of the Cercidiphyllaceae or Tetracentraceae while others have leaf morphologies suggesting alliance to these families. Cercidiphyllaceae and Tetracentraceae The Cercidiphyllaceae is an east Asian family of trees consisting of one genus and two species. Carcicichynm japcnicum Siebold and Zuccarini is native to Japan and central and western China: 9.3331312112113331 mnifisum (Nakai) Nakai is endemic to Honshu, Japan (Spongberg, 1979). The two species are very similar but can be 155 distinguished by minor leaf, stipule, follicle, and seed characters, and the length of the short shoots. Concerning the taxonomic placement of the family, Cronquist (1981) says that it "is generally regarded as related on the one hand to the Hamamelidaceae (especially W) and on the other to the Trochodendrales and Magnoliales". The Tetracentraceae is a monotypic family, native to Nepal, central and southwestern China, and northern Burma (Cronquist, 1981). Iccraccncrcn.§incncc Oliv. and the only species of the Trochodendraceae, Wm azalicicca Siebold and Zuccarini, constitute the order Trochodendrales. Cronquist (1981) regards the order as "the most archaic surviving group of Hamamelidae"; both families also have been associated with the Magnoliidae, particularly on the basis of vesselless wood. The status of fossil trochodendroids The assessment of the taxonomic affinities of fossil taxa is clearly dependent upon a thorough understanding of the potentially related living taxa. However, it is at this fundamental level that problems first arise when the works of modern authorities are consulted. Net only have the familial affinities of the fossil trochodendroids been elusive, but disagreement has existed over the diagnosis of the relevant living families. In commenting on the ability to distinguish between W and carcidimuam in the fossil record, Bailey and Nast (1945) remarked that the 156 leaves of these extant genera are so distinct that differentiating them as fossils could only be difficult if hypothesized overlap actually existed. Wolfe (1977), on the other hand, stated that "the leaves of extant W and W are indeed difficult to distinguish." Disagreements among modern workers might be a telltale sign that the separation of these extant taxa does include some pitfalls, but perhaps not so many as Wolfe implies. In recent years several authors have considered the foliar morphological criteria for recognizing the Cercidiphyllaceae. Chandrasekharam (1974) and Tanai (1981) have been the most thorough in discussing the modern leaves. To understand the mum-like leaves dominating the Paleocene Genesee flora, Chandrasekharam (1974) made extensive quantitative and qualitative observations of select foliar architectural features of living W. However, although he utilizes an extensive data base from the extant species to provide criteria for the segregation of his Genesee material into three species of W, and at various points contrasts the Cercidiphyllaceae with W, Smilax, EQDfllnfi, and other genera, he does not provide family-level diagnostic criteria. Tanai (1981) in revising the Milan-like leaves from the Paleogene of northern Japan does provide a family level foliar diagnosis. He distinguished extant garcicichylm leaves from 29.01.111.15 on the basis of smaller areoles, thicker freely-ending 157 veinlets, larger marginal glands with pointed setae, and thicker tertiary veins in 252911115. W is distinguished upon the basis of marginal gland morphology. He characterizes the marginal glands of carciciphyuam as being globular in shape and sometimes projecting out of the teeth, while glands of W are capped by undetached setae, gradually expand toward the tooth apex in a conical fashion, and do not protrude beyond the margin. He notes similarities between these two taxa to be size and shape of the areolation, and veinlets with two or three freely-ending branches. Among the trochodendroids, the foliar morphological and architectural differences between gcmicichyllnm and W are the thorniest because of their many similarities and the attending difficulties in determining fossil material. Chandrasekharam (1974) reported that W is distinct in having serrate margins with glandular tips and acuminate apices. An examination of fifty leaves showed that the average angles of departure for the alpha pectinal veins is approximately 15°, for the first strong superior secondary vein is approximately 17.5°, and for the alpha abmedials is approximately 20°. In addition, vein islets are regular and intruded by once or twice branched veinlets. Wolfe (1973) distinguishes carciciphyiinm on the basis of six orders of venation, and intercostal venation which is "formed primarily by closely spaced veins directly connecting the secondaries." Wolfe 158 (1973) considers some of Brown’s (1939) Eocene chciciphyiiam leaves, and some of MacGinitie's (1941) MW element-3m to be mm. but he does not explicitly explain his reasoning for this judgment. In his subsequent paper on the Paleogene floras of Alaska, Wolfe (1977) separates the two taxa by the more elongated leaves, and larger, more equally sided teeth of W. But his most definitive criterion is the apical glands of the teeth which are connected by veins to the adjacent sinuses (i.e. chloranthoid teeth of Hickey and Wolfe, 1975) in mm, but not in W. However, a consensus is lacking concerning tooth architecture as Crane (1984) regards both of these taxa to have chloranthoid teeth. Tanai (1981) notes Wolfe’s criterion of unbraced marginal glands in W, and states that the same condition is sometimes present in 9- Wm Apparently, Heer (1876; in Crane and Stockey, 1985) was the first to note the similarity of some actinodromously veined fossil leaves to the genus W. The first erection of a form genus, Ircchcdcndrcidca, to accomodate leaves that resembled carciaiphyiinm was by Berry in 1922 (Crane, 1984). In 1939 Brown reported on the cooccurrence of Trcchcccnczcidas and similar leaves with Nyccidinm infructescences and seeds at 30 separate North American localities and suggested that they belonged to the same plant. Four species of Wm were erected by Brown from this suite of 159 leaves on morphological and stratigraphical grounds, but later he found difficulty in maintaining some of them (Brown, 1962). Despite the ground gained in recent years in understanding fossil cerium-like leaves the situation remains complex. Wolfe (1966) revised Brown's 1939 classification and split Brown’s W arciigmm into five separate species which he felt might even represent five families. His principal criterion for the splitting was variable ultimate venation. These five taxa are Qgcculus flahella (Newberry) Wolfe. Trochcdendrcides..serrnlata. (Ward) Wolfe. Dicetxlenhxllum richardacnii (Heer) Wolfe, and two undescribed species. In part, Wolfe’s impetus for initially suspecting that these taxa were not Cercidiphyllaceae was Chandler's (1961) conclusion that the Magician considered by Brown to be cercidiphyllaceous, was, in fact, not. However, Crane (1984) reexamined the W reproductive material and found it to belong to the Cercidiphyllaceae although not the modern genus. Criticism of Wolfe's treatment of S2- arcticnm has also come from Chandrasekharam (1974) who found that ultimate venation was a tenuous taxonomic character in light of the amount of variability in the two extant species. Hickey (1977) uses the phrase, "cazcicipmm arcticIm complex" to refer to the five taxa segregated by Wolfe plus others of similar morphology. His use of this term is strictly morphological, though, as he 160 includes within it "9999111115" flabcua and W narxazcciatna, which he assigns to the Menispermaceae. Current opinion, however, has again come full circle, and "W" flaw is now regarded as belonging to the Trochodendrales because of its repeated association with the infructescence Ncrccnakiclcia, now known to be in the Trochodendrales (Crane, 1989). Another fossil leaf, formerly thought to belong to the Vitaceae, "W" acazifclia (Newberry) Brown, is now thought to be a trilobed form of the Trochodendrales (Crane, 1989). An extensive collection of leaves from the Paleocene of western Canada was incorporated by Chandrasekharam (1974) into the modern genus and divided into three species, C.- gcncafliancm Chandrasekharam, c. cam (Newberry) Chandrasekharam, and c. ficxncacm (Hollick) Chandrasekharam. This treatment of these three taxa is especially significant because he based their delimitation upon a statistical assessment of a large population of the leaves of both extant species. However, Crane and Stockey (1985) remark that these three fossil species are "extremely difficult to separate." Recently, two partial "whole plant" reconstructions of cercidiphyllaceous plants from the early Tertiary bear foliage remarkably similar to that of the living genus. Leaves from southern England, Trcchcdcndrcicas matuichii (De la Harpe) Crane, are very close to extant W (although dimorphic foliage is unknown) but were kept in the form genus because the "reconstructed 161 plant", called the "Win plant" for associated infructescences, bears some organs that are distinct from the modern genus (Crane, 1984). The most thoroughly known Wan-like plant is m cpciraii Crane and Stockey from the Late Paleocene of Alberta, Canada. Crane and Stockey (1985) apply this single binomial to several organs, including pistillate inflorescences, shoots, and seedlings, which they have found in intimate association. The leaves of mm are "strikingly similar" to extant W, and the reproductive organs are also similar to previously described taxa, but they apply a new name because this plant is known from considerably greater detail than any other. Based primarily on reproductive organs, both the "Magician plant" and lcflrca are considered to be extinct genera within the Cercidiphyllaceae. Diagnosis of the Cercidiphyllaceae and Tetracentraceae Gross leaf architecture similar to the Cercidiphyllaceae and Tetracentraceae, that is, elliptic to broadly ovate leaves with actinodromous and acrodromous venation, is fairly common among a diversity of extant woody taxa such as P93111115, cercia, Smilax, mm, W, and other genera. Leaves of this general architecture also often share similarities in the courses of their secondary veins. These commonalities can, and frequently' do» obfuscate ‘the identity of fossil leaves hearing this general morphology. However, the extant 162 Cercidiphyllaceae and Tetracentraceae can be distinguished from each other and from similarly appearing taxa upon the basis of leaf morphology. Leaves of the Cercidiphyllaceae can be identified by several features. Foliar dimorphism, with respect to the leaves borne on long and short shoots, is a characteristic of both extant species. However, its utility in diagnosing the family is limited since Crane (1984) has not found Imbadendmides 3213531121111. (the "Winn am plant from the Paleocene of England) to be dimorphic. However, J_Q_f_f_r_§_a apaiiaii (from the Paleocene of Canada) is dimorphic, and it is reasonable to expect other extinct members of the family to bear dimorphic foliage. Generally, in the extant taxa, short shoot leaves are quite broad, even to the point of being orbicular, and they have a cordate base; long shoot leaves are distinctly narrower, that is, ovate and have a truncate to rounded or cuneate base. Short shoot leaves normally have 7 primary veins, and long shoot leaves usually have 5 primary veins. The alpha pectinal veins are much more divergent (50-105 degrees) than in Iccraccnczcn. Wolfe (1973) has noted that carcicimm has six orders of venation. Among the more helpful diagnostic traits is the morphology and architecture of the ' leaf margin. Margins vary from crenate to rounded serrate to entire. In all cases, the leaves bear globular glands that may be either emergent or non-emergent, and occur both on tooth apices and in the sinuses between teeth. Tooth architecture has 163 been termed chloranthoid by Crane and Stockey (1985) and Wing (1981), but I prefer to call it "mixed chloranthoid" because of the differences between it and the classical chloranthoid type of Hickey and Wolfe (1975). In standard chloranthoid teeth, such as in W and W, the apical gland is connected to both adjacent sinuses (or sinus regions) by a "bracing" vein. As noted by Tanai (1981), some gczciciphylm leaves are like this. Others, however, have the apical gland connected to the sinus by a series of loops, or a vein may extend from a sinus toward the gland but not connect to it, or the gland may only be fed by a central vein, entirely lacking bracing veins. When the glands occur in the sinuses between teeth, as they frequently do, the chloranthoid terminology obviously cannot apply. The Tetracentraceae can also be recognized on the basis of foliar morphology and architecture. Bailey and Nast (1945) regard the uniformity in gross morphology of the leaves to be diagnostic in relation to the dimorphism of extant carcicichyiim. Uniformity is seen in the generally ovate shape and attenuate to broadly acuminate apices. However, the leaves do exhibit some variability in their bases which range from cordate to truncate. Primary, secondary, and tertiary veins also exhibit less variability than they do in carciciphylinm. Primary venation consists of two or three pairs of lateral primary veins, of which the inner pair is more steeply ascending (i.e. narrower 164 angle between alpha pectinals), and is more nearly parallel to the upper midvein, than in W. In the course followed by the alpha pectinal veins, Iccraccntrcn is more like certain species of zizypnaa than garcidichyiium. Chandrasekharam (1974) reported the inner primary angle to be about 30 degrees. The beta pectinal veins (second pair of lateral primaries) are much weaker than the alpha pectinals, and correspond in size to the first vein in the series of loops formed by alpha abmedial secondary veins. Secondary veins depart abmedially from all primary veins, ascend steeply, and consistently form strong brochidodromous loops. garciciphyiiam also has secondaries which form brochidodromous loops, but they are not as strong, nor do they possess the regularity of W. Tertiary veins also form strong brochidodromous loops exmedially to the secondary loops. Chandrasekharam (1974) and Crane (1984) have used the terminology, "strong superior secondary and weak secondary", to aptly refer to the pattern in carcidiphyiinm where weak secondary veins departing from the lower midvein abruptly increase in strength along the upper midvein. This condition has not been observed in Iccraccnczcn. Instead, the secondary veins departing from the midvein progressively increase in strength distally and are generally more uniform. All of the primary and secondary vein departure angles that were measured were smaller than the corresponding angles in carcicichflm. Two additional characteristics are especially helpful 165 in distinguishing Wm leaves from similarly appearing taxa. One of the most unique features of the leaves is the presence of petiolar (stipular?) flanges that are connected to the petiole and cover the axillary bud. I have never seen purported fossil W in the literature which was reported to have petiolar flanges. Distinct marginal teeth are also diagnostically important. Leaf margins have teeth with nearly equal sides (slightly serrate), approximately equal size and evenly spaced. Teeth always bear apical glands which, as Tanai (1981) noted, are broader at the apex and narrow proximally. Vasculature of the teeth is chloranthoid, as described above. Affinities of the fossil garciciphyiiam-like leaves The fossil canciciphyiiam-like leaves have characteristics found in several extant taxa as well as characteristics unshared. with known Tetracentraceae and Cercidiphyllaceae. Table 2 compares the foliar morphology of these leaves with Tctraccntrcn sincnsc, extant Cercidiphyllum, chfzca, and Ircchcdcndrcidcs pzcstyichii. Leaves of the Blackhawk fossils are actinodromously veined with strong alpha pectinal veins and quite weak beta pectinal veins. The alpha pectinal veins have a narrow angle of departure and their course approximately parallels the midvein in the upper half of the lamina. These features are consonant with both IQLIQQQDLIQD and Zizxphna, 166 and quite distinct from the short shoot leaves of Dimorphism is not present in this population of fossil leaves although some variation in gross shape does occur. Leaf shape varies from ovate to elliptic (usually in the smaller leaves); leaf bases are obtuse to rounded, and leaf apices are acute to attenuate. Although long shoot leaves of g. japcnicgm are often ovate with a rounded base, the attenuated apex and narrow lamina of the fossils are more like Iccracaaczcn. Long shoot leaves of both Icgraccnczcn and Q. japcnicam are more similar to the fossils than the short shoot leaves of either. Weak beta pectinal veins are similar to Icczaccncncn and long shoot leaves of garciciphyiiam, in being the first in a series of brochidodromous loops formed by the alpha abmedial (secondary) veins. These veins form loops which parallel the alpha pectinal veins, in contrast to the usual condition of greater divergenoe and rounder loops of Tctraccntrcn and carcidipnyiinm. Some long shoot leaves of both extant species, though, are similar to this condition. The superior secondary vein to which the beta pectinal vein connects is much stronger than the secondaries proximal to it, which also occurs in carciciphyiinm. The course of the tertiary veins between the midvein and alpha pectinals is only faintly visible in several leaves, but it appears to be apically directed with lateral branches, some of which form chevrons. Better preserved leaves need to be 167 “~33 3 33028 one. AI III-lam .nunn name-ml .6. £633.33 5 canal—en he...» an $3.853 one 33 .333 IA».- 5 383.533 no II... 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Petioles are missing or broken in many leaves so that it is not known whether the petioles bore flanges, in the fashion of Tetracentron- The margins of the leaves and tooth architecture are preserved in a number of specimens and provide an important reference for taxonomic judgments. The teeth are serrate, sometimes bluntly so, and usually occur in pairs where a larger sinus separates every other tooth. Some leaves possess a larger pair of teeth that flank each side of the upper one-quarter of the lamina, and thereby provide a "shoulderedfl appearance. Tooth. architecture is chloranthoid. Some teeth clearly show marginal glands which expand toward the tooth apex as Tanai (1981) noted for W. However, the teeth do not have the consistency of size and shape that are found in extant Wu. In summary, tooth architecture and glands are like those found in Tetracentrgn rather than W, but tooth shape and placement are unlike the extant members of these families. The fossil gergidiphyllum-like leaves from the Blackhawk formation do not fall clearly into any extant family that I have investigated. The leaves were tentatively assigned by Parker (1976) to W argtignm based upon a cursory examination. But, despite a superficial resemblence to cercidiphyllnm, leaf morphology and architecture are sufficiently distinct from this taxon 169 that it cannot be placed in the Cercidiphyllaceae without evidence from reproductive organs that would show the leaves to be, indeed, atypical to the family. Those fossil leaves from the Paleocene known to belong to the Cercidiphyllaceae. 19.1fm. W W. and the Wm from western Canada, are also distinct from the Blackhawk leaves. The leaves are quite distinct from Zizyphus in terms of tooth architecture. The case for a tetracentraceous placement of the fossils is the most compelling due to the overall shape, primary and secondary vein courses, relatively narrow vein departure angles, chloranthoid teeth, and nature of the marginal glands. Hickey and Wolfe (1975) regard tooth architecture in angiosperm leaves to be relatively more conserved evolutionarily than other morphological features. If this is true, the chloranthoid nature and apically expanded marginal glands of the teeth are strong evidence in favor of alliance with the Tetracentraceae. The question raised earlier concerning the recognition of unknown variability in the fossil representatives of a higher taxon is relevant to the problems of these trochodendroid fossils. How far can a fossil taxon morphologically diverge from an extant monotypic family and still be considered as an historic part of the family? In the case of the Platanaceae, several living species and numerous Tertiary form-species provide a good representation of familial foliar morphological diversity, 170 and therefore a good basis for judging the conservability of architectural features. A monotypic family, on the other hand, does not possess such variability, especially if unequivocal fossil representatives are unknown. W W, the only extant member of the Tetracentraceae, may be the final representative of a historically diverse family. Judgments concerning the placement of fossil taxa, especially Cretaceous forms, into the Tetracentraceae (or other extant families), must be based upon foliar architectural characters that are thought to be evolutionarily conservative. In addition, the presence of fossil reproductive organs would, of course, greatly enhance the recognition of the historical members of a monotypic family. A collection of better preserved leaves from the Blackhawk Formation that fully display tertiary and quaternary venation, and cuticle, is needed for further confirmation of the tetracentraceous alliance of these fossil trochodendroid leaves. 171 SUMMARY The determination of the systematic affinities of fossil leaves is improved with a thorough understanding of potentially related extant taxa. Likewise, the assessment of infraspecific variability in fossil taxa, particularly among morphotypes whose modern representatives are known to be heteromorphic, should proceed from an understanding of the ranges of the modern variability. Upper Cretaceous platanoid and trochodendroid leaf fossils are known to commonly exhibit intergradations in morphologies that make the systematic boundaries difficult to ascertain. The purpose of this study was to document the patterns of variability in modern Rhianna. magnum. and Wu leaves in order to evaluate the systematic affinities of always-like and Cercidiphyllum-like leaf fossils from the Upper Cretaceous Blackhawk Formation of central Utah. The following conclusions can be made from this study: 1. Foliar heteromorphism was found to characterize Platanus xnxmgg. Platanus occidentalis. Elm: racemosa, and W W. Shoots from all of these species bear leaves showing heterophyllic patterns of development. 2. The variability in mm KM was examined in the greatest detail. Three types of crown shoots can be distinguished by differences in their heterophyllic patterns: inflorecence-bearing shoots, Type I non- 172 inflorescence shoots, and Type II non-inflorescence shoots. Several morphological characters followed progressive patterns of change through successive leaves of these shoots. Lamina area and perimeter lengths increased through successive leaves, except for a tapering-off later in the season, presumably from incomplete development. Lamina basal angles increased in the leaves along a shoot and the lamina bases often became quite reflexed in the late-season leaves. Leaf apices generally became more attenuated. The number and size of teeth are highly variable; tooth size generally' decreased. distally’ along each leaf lobe and the number of teeth increased through successive leaves on a shoot. The leaves of shoots bearing an inflorescence and Type I shoots initially have very few teeth and eucamptodromous and brochidodromous secondary venation. Successive leaves acquire more teeth, both the typical platanoid type and minute papillate teeth. The papillate teeth are accompanied by semicraspedodromous secondary venation. As the number of platanoid teeth increases so do the craspedodromous secondary veins which enter these teeth. Type II non-inflorescence shoots are distinct by having the lamina base of the first leaf acute to obtuse and broadly decurrent (rather than truncate as in the other two shoot types); in addition, many teeth, including papillate teeth, occur on the first leaf. The first leaf of all three shoot types generally lack lateral lobes, but succeeding leaves progressively develop these 173 lobes. Sinuses between the lateral lobes become more deeply incised through the heterophyllic series. 3. Inflorescence-bearing shoots of Blatanus thbrifia display a "reset" phenomenon where leaves developed after the inflorescence node repeat some of the heterophyllic patterns present in the pre-inflorescence leaves. Morphological features which follow this pattern are lamina size, lamina base angle, lateral lobe sinus incision depth, and the first leaf in the sequence has an unlobed form and pinnate venation. 4. One type of non-inflorescence canopy shoot of Blatanus W was examined and found to display the same heterophyllic trends as E. Xhmma Type I shoots. Inflorescences terminate shoots in E. occidentalis so that "reset" sequences do not occur. 5. Shoots from a stump of E. thbriga or E. occidentalis and shoots from the base of B. W trees display heterophyllic trends similar’ to, but differing in some essential details from, the heterophyllic sequences of the respective canopy shoots. The initial leaves are large with shallow lobe sinuses, many teeth, and dissymetrical arrangements of secondary and tertiary venation. Higher numbers of intersecondary 'veins and. reticulate ‘tertiary veins add to the less-organized aspect of these early leaves. Lamina bases from the same st-ump shoot are conspicuously decurrent. The development of lobation increases in successive leaves of both taxa. The leaves of Platanus racemosa that occur midway along a sucker shoot 174 possess small "accessory" lobes in the sinuses between the central and adjacent lobes. The heterophyllic patterns in leaves from the sucker shoots of both species converge upon a morphology quite similar to canopy shoot leaves. 6. The family Platanaceae can be recognized by a suite of foliar characters although no single character is uniquely diagnostic. The extant subgenus Blatanus is characterized by basally or suprabasally actinodromous or palinactinodromous primary venation, percurrent to reticulate tertiary veins, chevrons formed by tertiaries in the axils of the primary veins, orthogonal quaternary veins, platanoid teeth, swollen petiole bases that cover the axillary bud, and heteromorphism, particularly heterophyllic patterns of development. The subgenus Qastanggphyllum is, however, quite distinct in having elliptic leaves, pinnate venation, different marginal venation, and exposed axillary buds (Schwarzwalder and Dilcher, in press). Blatanus Kgrzii, the only species in the subgenus, was not studied and it is not known if its leaves are heteromorphic. 7. The Way‘s-like leaves from the Upper Cretaceous Blackhawk Formation can be placed within the Platanaceae based upon their possession of most of the above characters. They differ from extant subgenus Blatanns in having craspedodromous secondary veins that generally appear to terminate at an entire margin; some do terminate in minute papillate/spinose teeth, but platanoid teeth are 175 absent. The tertiary veins form very weak chevrons or simply a straight bridge in the axils of the primary veins. Previous preliminary work on the Blackhawk platanoids assigned the leaves to two separate Elatanus form species based upon the presence or absence of a decurrent lamina base. This study has shown that such variability is both diagnostic for the family Platanaceae and commonly occurs as infraspecific variability in some extant species. A treatment of the Blackhawk platanoids as a single species is therefore considered to be a more biologically realistic approach. The Upper Cretaceous form genus most closely resembling the Blackhawk platanoids is grgdngria. 8. The leaves of the Cercidiphyllaceae and Tetracentraceae are quite similar to each other in some features of gross morphology and vein architecture, but some morphological characters do exist that can be used to distinguish them. This study concurs with previous studies that separation of the leaves of these two families may be based upon the following characteristics: foliar dimorphism in cercidiphyllum; attenuated leaf apices and smaller departure angles of the primary and secondary veins in Tetracentzgn. Tooth shape, gland shape and placement, and tooth architecture are also distinct between these two taxa. In addition, this study has noted that the primary, secondary, and tertiary venation of mm is less variable than in W, and that successive secondary veins which depart from the midvein gradually become strengthened distally in Igtraggntrgn rather than an 176 abrupt strengthening as in Qgrgidiphyllum. 9. The fossil. Qezgidiphyllumelike leaves from ‘the Blackhawk Formation can be placed into the Tetracentraceae rather than the Cercidiphyllaceae based upon the following leaf morphological characters: a narrow angle of departure for the alpha pectinal veins, attenuated leaf apices, chloranthoid tooth architecture, and marginal glands which become broader toward the tooth apex and always occur at tooth apices, never in sinuses. 177 APPENDICES APPENDIX A GLOSSARY or SELECTED TERMS1 acrodromous - two or more primary or strongly developed secondary veins running in convergent arches toward the leaf apex. actinodromous - three or more primary veins diverging radially from a single point. See figure 4a. brochidodromous - secondaries joined together in a series of prominent arches. See figure 5, b and c. craspedodromous - secondary veins terminating at the margin. See figure 4b. eucamptodromous - secondaries upturned and gradually diminishing apically inside the margin, connected to the superadjacent secondaries by a series of cross veins without forming prominent marginal loops. See figure 38. intersecondary vein - thickness intermediate between that of the second and third order veins; generally originating from the medial primary vein, interspersed among the secondary veins, and having a course parallel to, or nearly so, to them. See figure 4 c and d. palinactinodromous - primaries diverging in a series of dichotomous branchings, either closely or more distantly spaced. See figure 14, c through k. pectinal vein - a vein which subtends abmedially a distinct series of more or less parallel branches as thick as, or thinner than, themselves, in a similar manner to teeth of a comb. Pectinal veins are normally primary or secondary although they may be of any vein order; they may be basal or suprabasal in origin, and they may bear admedial branches in addition to the abmedials. See figure 4. percurrent - tertiaries from the opposite secondaries joining. See figure 4 or 13. semicraspedodromous - secondary veins branching just within the margin, one of the branches terminating at the margin, the other joining the superadjacent secondary. See figure 37 a and d. 1 Definitions of the leaf architectural terms presented here are taken verbatim from Hickey (1979), except for the definition of pectinal veins which is taken from Spicer (1986). 178 APPENDIX B VICOM COMB FILE * Program: 8000.&.LEAVES.VC David Huber April 14, 1988 it Vicom 1800 CIM command file for digitizing a leaf, thresholding it and penmeter measurements. * * interactively, optionally patching holes (#DRA 2), then taking the area * . :I: CALL O.&.CCD 3k REP ERE Repeat loop begin CAM GRE (OFF) * Prepare next leaf for digitization Pause until user is ready to continue ause Digitize the next leaf DIG l * Perform an interactive thresholding operation * on the leaf image #THR l * Turn on the graphics mode GRE * Shift the data into the graphics bits for AREA * and perimeter measurements to be possible LSH 1>2 (13) * Call up #DRA for optional manual leaf filling in #DRA 2 * Get AREA measurement ARE 2 * Get PERIMETER measurement PER 2 * Pause so numbers can be written down PAUSE *"U**** 179 IPPIIDIX C Table 3. Statistical sullary of foliar lorpholoqical data of Blatanns 1011:1111 and Blatant: occidentalia nnlber of data. 58, standard error. 80, lissing data. 3 4. 6. 7. . Pre-inflorescence leaves 2. 18181111 . Post-inflorescence leaves Llhlhtidl Ion-inflorescence shoot (Type I) E- 10181111 Ion-inflorescence shoot (Type II) 8- 10181118 . Stnlp shoot leaves 8- Xh!hlidi(?) total for inflorescence plus non-inflorescence shoots of E. Xhthtida Ion-inflorescence shoot Lucidantalia n/t ratio lean = .459 lin. = .395 lax. = .532 SE = .0182 l = 7 lean = .405 lin. = .322 lax. = .534 SE = .0242 I: lean = .461 lin. = .335 lax. = .562 SE = .016 l = 16 lean = .562 lin. = .53 lax. = .597 SE = .0139 I: lean = .614 lin. = .512 lax. = .719 SE = .0218 l = 12 lean = .454 lin. = .322 lax. = .597 $8 = .0113 I = 42 lean = .526 lin. = .417 Ill. 8 .632 58 = .0176 l = 17 IIEBEJ 811 angles are in degrees. s/l ratio lean = .49 lin. = .388 lax. = .554 88 = .0253 I = 7 lean = .616 lin. = .477 lax. = .722 $8 = .0295 I = 9 lean = .548 lin. = .391 lax. = .694 $8 = .0203 = 16 lean = .485 lin. = .452 Ill. = .522 SE = .0158 l = 4 lean = .394 lin. = .271 lax. = .51 58 = .0211 = 12 lean = .54 lin. = .386 lax. = .722 58 = .0139 l = 43 lean = .439 lin. = .205 Ill. = .546 $8 = .0198 I = 17 Ill ratio lean .924 lin. .791 lax. 1.05 SE = .0301 I = 8 lean = .909 lin. .833 lax. 1.01 88 = .0186 l = 11 - H a: . II II I. o a ...—a w .995 .777 lax. 1.31 SE = .0957 I = 5 - H. :1 II I. " lean = 1.16 lin. = .828 lax. 2.11 SE = .1075 l = 12 lean = .924 lin. = .777 lax. = 1.31 88 = .0136 I = 48 lean .859 lin. .76 lax. .943 88 = .0119 l = 18 . lean Basal angle, . lean = 232 l1n. = 180 lax. = 267 SE = 9.803 I = 8 . lean = 228 lin. = 180 lax. = 276 SE = 9.157 I = 11 242 145 316 1.66 Iln. lax. SE I II II H 0'5 H II II II . lean = 116 lin. = 88 lax. = 164 SE = 14.46 I = 5 . lean = 142 lin. = 56 lax. = 228 SE = 17.35 I = 12 . lean = 219 lin. = 88 lax. = 316 SE = 7.45 I = 47 lean = 222.5 lin. = 132 lax. = 306 SE = 12.19 I = 17 Apical angle lean = 37.4 lin. = 23 lax. = 56 SE = 3.186 I = 11 lean 25.6 lin. 16 lax. 32 SE = 1.369 I = 16 lean = 33.8 lin. = 23 lax. = 46 SE = 4.641 I = 5 lean = 52.5 lin. = 25 lax. = 107 SE = 7.829 I = 12 lean = 31 lin. = 16 lax. = 56 58 = 1.388 I = 47 lean = 26.7 lin. = 20 lax. = 42 58 = 1.617 I = 15 1.831 lulher of teeth lean = 10.8 lin. = 8 lax. = 16 SE = 1.031 N: lean = 37.1 lin. = 29 lax. = 55 SE = 2.23 I = 11 lean = 47.3 lin. = 10 lax. = 102 SE = 7.606 I = 17 lean = 50.8 lin. = 41 lax. = 63 58 = 3.734 I = 5 lean = 54.8 lin. = 30 nor. = 84 58 = 5.445 I = 12 lean = 35.4 lin. = 8 lax. = 102 58 = 3.488 I = 48 lean =-24.2 lin. = 7 lax. = 47 $8 = 3.453 I = 17 Angle between central and lateral lobes lean = 105 lin. = 69 lax. = 129 SE = 4.303 I = 14 lean = 66.6 lin. = 44 lat. = 98 58 = 4.36 I = 15 lean = 99.7 lin. = 56 lax. = 131 $8 = 3.288 I = 31 lean = 97.9 lin. = 79 lax. = 119 SE = 4.969 I = 7 lean = 118 lin. = 81 lax. = 148 SE = 3.895 I = 22 lean = 92.3 lin. = 44 lax. = 131 $8 = 2.542 I = 79 lean = 116 lin. = 98 lax. = 149 $8 = 1.922 I = 33 Distance froa lalina- petiole juncture to pectinal origin lean = .113ca lin. = 0.0ca lax. = .3ca SE = .026 I = 16 lean = .453Cl lin. = 0.2ca lax. = 1.1ca 58 = .041 I = 20 lean = .ZBSCI lin. = 0ca lax. = .45ca 58 = .0262 I = 20 lean = 0.7250] lin. = 0.3ca lax. = 1.2ca SE = 0.092 I = 10 lean = 2.38Cl lin. = 0.9ca lax. = 3 4ca SE = 0.17 I = 21 lean = 0.36CI lin. = 0.0ca lax. = 1.2ca SE = 0.036 I = 60 lean = 0.1170l lin. = 0.00] lax. = 0.7 $8 = 0.033 I = 32 .1632 Angle of pectinal departure lean = 46.4 lin. = 34 lax. = 60 SE = 1.94 I = 16 lean = 49.5 lin. = 38 lax. = 64 SE = .38 I = 22 lean = 48.6 lin. = 33 lax. = 65 SE = 2.18 I = 22 lean = 34.1 lin. = 25 lax. = 44 SE = 1.946 I = 10 lean = 41.1 lin. = 24 lax. = 51 SE = 1.36 I = 21 lean = 45.5 lin. = 25 lax. = 64 SE = 1.091 I = 62 lean = 54.06 lin. = 36 lax. = 70 SE = 1.674 I = 34 Angle of secondary vein departure lean = 49.8 lin. = 38 lax. = 58 SE = 1.32 I = 16 lean = 52.8 lin. = 46 lax. = 62 58 = .908 I = 22 lean = 52.5 lin. = 44 lax. = 66 SE = 1.19 I = 22 lean = 51.2 lin. = 36 lax. = 59 SE = 2.169 I = 10 lean = 49.3 lin. = 28 lax. = 65 SE = 1.7 I = 24 lean = 51.7 lin. = 36 lax. = 66 SE = 0.695 I= 62 lean = 54.58 lin. = 45 lax. = 64 58 = .796 I = 36 Distance between secondary vein departures lean = 1.91ca lin. = 1.2ca lax. = 3.2ca 58 = 0.141 I = 16 lean = 2.02ca lin. = 1.2cn lax. = 2.9ca SE = 0.085 I = 22 lean = 2.44ca lin. = 1.0ca lax. = 3.50] SE = .1297 I = 22 lean = 2.27cl lin. = 1.4ca lax. = 3.2ca SE = 0.175 I = 10 lean = 2.31cn lin. = 0.8ca lax. = 5.9cn SE = 0.271 I = 24 lean = 1.91cl lin. = 0.7ca lax. = 3.2ca $8 = 0.0678 I = 62 lean = 1.53ca lin. = 0.9cl lax. = 2.3CI SE = 0.0641 I = 36 Angle of departure of tertiary veins lean = 80.75 lin. = 70 lax. = 90 88 = 1.399 I = 24 lean = 81.73 lin. = 62 lax. = 90 SE = 1.328 I = 33 lean = 81.3 lin. = 60 lax. = 90 SE = 1.298 I = 33 lean = 84.7 lin. = 75 lax. = 90 SE = 1.337 I = 15 lean = 76.7 lin. = 56 lax. = 90 SE = 1.282 I = 36 lean = 82.1 lin. = 62 lax. = 92 SE = 0.694 I = 93 lean = 86.4 lin. = 70 lax. = 97 58 = 0.682 = 54 1.Ei3 Distance betveen tertiary vein departures lean = 0.398 lin. = 0.2 lax. = 0.65 SE = 0.025 I = 24 lean = 0.294 lin. = 0.2 lax. = 0.4 58 = 0.012 I = 33 lean = ID lin. = lax. = 58 = lean = 0.363 lin. = 0.15 lax. = 0.6 58 = .033 I = 15 lean = 0.449 lin. = 0.2 lax. = 0.8 SE = .0267 I = 36 lean = 0.334 lin. = 0.15 lax. = 0.65 SE = 0.0111 I = 93 lean = 0.3 lin. = 0.1 lax. = 0.5 SE = 0.0126 I = 54 LITERATURE CITED LITERATURE CITED Agrios, G.N. 1988. 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Blackhawk trochodendroid leaf. 7/30/70 III Blackhawk trochodendroid leaf. 194 Natural size. 6/30/85 7/30/70 II P510-001 47-112 P382-300 HICH 6 0001100