Description from Flora of China
Herbs twining or woody vines, rarely erect, small herbs. Rootstock rhizomatous or tuberous. Stem twining to left or right, pubescent or glabrous, sometimes prickly. Leaves alternate or opposite, petiolate, simple or palmately compound, basal veins 3--13, interstitial veins reticulate; leaflets of palmately compound leaves often ovate or lanceolate. Flowers usually unisexual (when plants dioecious, rarely monoecious), sometimes bisexual, solitary, clustered, or in cymules, these in a spike, raceme, or thyrse, these sometimes grouped into panicles. Male flowers: perianth lobes 6, in 2 whorls, basally connate or free; stamens 6, sometimes 3 reduced to staminodes or absent, inserted on perianth or receptacle; ovary rudimentary or absent. Female flowers: similar to male ones; staminodes 3, 6, or absent; ovary inferior, 3-loculed, ovules usually 2 per locule (more than 2 in a few small genera), placentation axile; styles 3, free. Fruit a capsule, berry, or samara. Seeds with a membranous wing or not; endosperm present; embryo small.
Ting Chih-tsun, Chang Mei-chen & Ling Ping-ping. 1985. Dioscoreaceae. In: Pei Chien & Ting Chih-tsun, eds., Fl. Reipubl. Popularis Sin. 16(1): 54--120.
About nine genera and 650 species: widely distributed in tropical and temperate regions, especially in tropical America; one genus and 52 species (21 endemic, two introduced) in China.
(Authors: Ding Zhizun (丁志遵 Ting Chih-tsun); Michael G. Gilbert)