Description from Flora of China
Herbaceous or woody vines. Rootstock often tuberous, sometimes above ground; branches striate, slightly twining. Petiole often very long, swollen at both ends; leaf blade deltoid, deltoid-rotund, or deltoid-subovate, peltate, papery, rarely membranous or subleathery, palmately veined. Inflorescences axillary or from axillary stems with leaves reduced or absent, rarely from old stems, usually umbelliform cymes, sometimes condensed into heads on discoid receptacles, often in compound umbels, rarely along thyrsoid axis. Male flowers: sepals in (1 or)2 symmetrical whorls of 3 or 4, free or occasionally connate at base; petals 3 or 4 in 1 whorl, rarely in 2 whorls or absent; stamens 2-6, usually 4, connate into a peltate synandrium, anthers dehiscing transversely. Female flowers: perianth symmetrical; sepals and petals each in 1 whorl of 3 or 4, or asymmetrical, sepal 1(or 2) and petals 2(or 3); staminodes absent; carpel 1, subovoid. Drupes red or orangish red, subglobose, slightly flattened on both sides, style scar near base; endocarp usually bony, obovoid to obovoid-rotund, abaxially bearing 1 or 2 rows of transverse ridges or columnar ornamentation on each side; condyle slightly concave on each side, perforate or not. Seed horseshoe-shaped; embryo horseshoe-shaped; endosperm fleshy; cotyledons subequal to or shorter than radicle.
Plants of this genus contain more than 50 kinds of alkaloids. Their tuberous roots are widely used in traditional Chinese medicine and as local medicines.
About 60 species: tropical and subtropical Asia and Africa, a few in Oceania; 37 species (30 endemic) in China.