Kansas Wildflowers and Grasses

ATLANTIC YAM

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Dioscorea villosa L.

[=Dioscorea quaternata J. F. Gmel.]

Wildcat Glades, Newton County, Missouri

Perennial vine

Height: 3-23 feet long

Family: Dioscoreaceae - Yam Family

Flowering Period: May, June, July

Also Called:

Wild yam.

Stems:

Twining, grooved or narrowly winged, glabrous or rarely sparsely pubescent.

Leaves:

Lower alternate, opposite, sub-opposite, or whorled, upper alternate; petiole 1.2 to 5.6 inches; blade 7-11-veined, ovate, 1.2 to 5.2 inches long, .8 to 5.2 inches wide, base cordate, margins entire, apex acute to acuminate, abaxial surface glabrous, glandular, or sparsely to densely pubescent.

Inflorescences:

Dioecious. Staminate inflorescences 1 per axil, panicle-like, branched, 1.2 to 3.2 inches long, pendent; cymes sessile, 1-3-flowered. Pistillate inflorescences 1 per node, spike-like, pendent, 1.6 to 8 inches long, 4-18-flowered.

Flowers:

Inconspicuous; perianth greenish white, rotate-campanulate; tepals 6, in 2 whorls of 3, basally connate, petal-like, ovate-elliptic, apex rounded or acute; staminate flowers .04 to .12 inch diam.; stamens 6; pistillate flowers .08 to .16 inch diam.; pistils 3; styles 3, distinct; stigmas 3.

Fruits:

Capsules greenish gold, ovoid to obovoid, .4 to 1.2 inch long, .2 to 1.4 inch wide, 3-winged; seeds 2 per locule, flattened or globose, flattened, winged.

Habitat:

Floodplain and oak-hickory forests, creek banks, thickets; sandy or rocky soils

Distribution:

East 1/5 of Kansas

Origin:

Native

Comments:

Dioscorea, for Dioscorides, a Greek physician and naturalist and villosa, soft-hairy, alluding to the leaves.

Atlantic yam inflorescence