Dioscorea villosa

Dioscorea villosa flower petal color is commonly known to be green to brown, or white. Lengths of the flower petals range from 0.5 to 2 mm (1⁄32 to 3⁄32 in). The flowers tend to grow out of the axil; this is the point at which a branch or leaf attaches to the main stem. There is only one flower present on the inflorescence.^{[verification needed]} The fruit of the plant is a capsule that splits and releases the seeds within to then begin the dispersal process^[9] The fruit of Dioscorea villosa ranges in size from 10–30 mm (3⁄8–1+3⁄16 in).^[10] The flower does not produce aerial bulblets. The leaves are heart-shaped, usually a whorl of four at each node, but there can be as many as nine in a whorl.^[11]

Synonyms of Dioscorea villosa include Dioscorea hirticaulis and Dioscorea villosa var. hirticaulis. Common names of Dioscorea villosa include wild yam, Atlantic yam, common wild yam, wild yam-root, yellow yam, colic root, and rheumatism root.^[2][12][13]

Dioscorea villosa contains diosgenin, which despite claims is not a phytoestrogen and does not interact with estrogen receptors.^[14] Other steroidal saponins are also found in the plant.^{[citation needed]}

Some of the English common names of this plant reflect its use in Native American and other traditional medicines.^[15] Native Americans in the southeast cultivated this plant.^[16] In traditional Russian herbal medicine, saponin extracts from the roots of various varieties of wild yam are thought to be an anticoagulant, antisclerotic, antispasmodic, cholagogue, depurative, diaphoretic, diuretic and a vasodilator.^[17]

There is little modern clinical research on Dioscorea villosa, and the one study of a wild yam-containing cream for menopausal symptoms failed to find any value from this therapy.^[18] According to the American Cancer Society, there is no evidence to support wild yam or diosgenin being either safe or effective in humans.^[19]