Dioscore'a villo'sa, Dioscorea, Wild Yam Root, Colic (Rheumatism) Root, N.F. -- Dioscoreaceae. The dried rhizome with not more than 2 p.c. of foreign organic matter; United States; moist thickets. Slender twining climber, dioecious; leaves ovate, cordate, acute; flowers greenis, panicles; fruit triangular winged capsule. Rhizome, knotted, woody, elongated, 6-20 Mm. (1/4-4/5') thick, often compressed, bent, branched, nodular, stem-scars above, slender tough roots beneath, pale brown, scaly; fracture short, tough, yellowish, scattered wood-bundles; odorless; taste starchy, insipid, acrid. Powder, whitish -- parenchyma cells, starch grains, few calcium oxalate raphides, fibrovascular bundles with tracheae and tracheids, epidermal tissue; contains resin, saponin body, starch (dioscorein--"Eclectic" resinoid), ash 2-7 p.c. Diaphoretic, expectorant, emetic; rheumatism, bilious colic. Dose, 3ss-1 (2-4 Gm.); 1. Fluidextractum Dioscoreae (diluted alcohol). 2. Tinctura Viturni Opuli Composita, 3.5 p.c. Decoction, Tincture, Dioscorein. gr. 1-4 (.06-.25 Gm.).