The taxonomic status of the plant species Iva annua, an ancient food seed domesticated by American Indians, is investigated through herbarium studies to answer questions about whether the three subspecies currently recognized are in fact valid. Metrics of the morphology demonstrate that the two extant subspecies should be treated as synonymous, leaving only 1 valid, existing subspecies, and one from the archaeological history of its domestication. The nutritional properties of the oil and its fatty acids, and protein and its amino acids were investigated. Qualitative analysis of the fatty acids showed the composition to be comparable to two other oilseed crops in the Asteraceae. The majority fatty acid is the 18:2 n-6 which is present at approximately three times the levels of the 18:1 fatty acid. Protein analysis, while showing that I. annua amino acid profiles are similar to Helianthus annuus and Carthamus tinctorius, also showed kernel protein levels considerably higher than previously reported for this species, roughly in the range of highs of more than 60 percent. These high nutrient levels mean that the contribution of Iva annua to the diet of the ancient Native Americans makes the enigma of its abandonment even more profound.
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