Perrenial glabrous, non-woody vines, often rhizomatous and/or tuberous. Leaves alternate, entire; stipules lacking. Inflorescence a spike, raceme or panicle; flowers usually bisexual, actinomorphic, each subtended by a small bract; bracteoles in 1 or 2 pairs immediately below the perianth; tepals 5, connate at base, imbricate; stamens 5, filaments inserted on the perianth; ovary superior, 1-celled; styles simple, 3-fid or 3; ovule 1. Fruit indehiscent, sometimes berry-like as the perianth segments enlarge and thicken in fruit.
4 genera and c. 15 species from southern North America to South America, Africa and Madagascar; 1 naturalised in Australia.