Sp. Pl.2: 1032. 1753
Phenology: Flowering mid spring–summer; fruiting late summer.
Habitat: Borders of bogs, swamps, marshes, river and lake margins, creek bottoms, sandy or rocky soils, moist or dry woods, hammocks, thickets, limestone or talus slopes, roadsides
Elevation: 0–1500 m
Dioscorea villosa is a highly polymorphic species, exhibiting complex patterns of variation across its geographic range. Characters that have been used previously to delineate taxonomic boundaries within this complex—pubescence, glaucousness, rhizome thickness and shape, length of internodes within the inflorescence, arrangement of proximal leaves, geometry of the stem, and fruit and seed size/shape—fail when individuals from all parts of the range and specimens representing both apical and basal portions of single stems can be examined. At its morphological extremes, D. villosa comprises 1) small vines with tightly congested inflorescences, winged stems, and variously pubescent leaves, occurring in bogs and branch swamps; and 2) robust plants, rigid at the base, the proximal leaves verticillate with large, glaucous blades, from the axils of which arise lax spikes or panicles, inhabiting rocky, upland woods and steep talus slopes. As one ascends from the Atlantic Coastal Plain through the Appalachians, continuing westward to the Great Lakes region, south to the Ozarks, and east to the branch swamps of Georgia, particular morphologies are associated with particular ecological conditions, independent of geography. As well as the morphological extremes, every intermediate condition of leaf, stem, and inflorescence architecture can be found, in all combinations, and variation may be encountered even within individual plants. What sort of genetic structure underlies these patterns of morphological diversity remains an open question. That there is a significant degree of genetic variability within the complex is evident from the chromosome counts thus far reported. Further research is needed to shed light on patterns of gene flow in the complex, and garden studies would be instructive as to the limits of individual plasticity. At present, I can find no natural gaps in the variation between the plants that have been called (albeit ambiguously; see H. H. Bartlett 1910) D. villosa and those called D. quaternata, and therefore I am treating the complex as a single species.
|Author||Lauren Raz +|
|Common name||Wild yam +, yam root + and colic root +|
|Elevation||0–1500 m +|
|Habitat||Borders of bogs, swamps, marshes, river and lake margins, creek bottoms, sandy or rocky soils, moist or dry woods, hammocks, thickets, limestone or talus slopes, roadsides +|
|Illustrator||John Myers +|
|Phenology||Flowering mid spring–summer + and fruiting late summer. +|
|Synonym||Dioscorea cliffortiana +, Dioscorea glauca +, Dioscorea hexaphylla +, Dioscorea hirticaulis +, Dioscorea longifolia +, Dioscorea lloydiana +, Dioscorea megaptera +, Dioscorea paniculata +, Dioscorea paniculata glabrifolia +, Dioscorea pruinosa +, Dioscorea quaternata +, Dioscorea quaternata glauca +, Dioscorea quinata +, Dioscorea repanda +, Dioscorea villosa glabra +, Dioscorea villosa glabrifolia +, Dioscorea villosa glauca +, Dioscorea villosa hirticaulis +, Dioscorea villosa paniculata +, Dioscorea villosa quaternata +, Dioscorea villosa vera + and Dioscorea waltheri +|
|Taxon name||Dioscorea villosa +|
|Taxon parent||Dioscorea +|
|Taxon rank||species +|
|Volume||Volume 26 +|