DIOSCOREACEAE, a family of monocotyledonous plants which includes the yam (q.v.), the black bryony (Tames com munis), and the elephant's-foot (q.v.). There are nine genera and about 220 species, all climbing herbs or shrubs with tubers or rhizomes at the base. The flowers are usually regular, unisexual, inconspicuous ; the parts are in threes.