3. Dioscorea villosa L. (wild yam)
88 d, e; Map 335
D. villosa f. glabrifolia (Bartlett) Fernald
Aerial stems from horizontal rhizomes, these 5–10 mm in diameter when fresh, relatively
straight, smooth and with few or no knobs or short side-branches. Leaves mostly
alternate below (rarely opposite or in whorls of 3), alternate above, 4–19 cm
long, heart-shaped, the base cordate and the tip acuminate. Aerial tubers not
produced. Fruits 13–25 mm long. Seeds 7–17 mm wide including the wing. 2n=60.
Scattered throughout the state (eastern U.S. west to Nebraska and Texas). Mesic
bottomland and upland forests, frequently on mesic, rocky slopes, thickets
along creeks, fencerows, railroad tracks.
For a discussion of the differences between this species and D. quaternata,
see the treatment of that species.