Description from Flora of China
Herbs or shrubs, rarely trees, erect, rarely scandent. Root usually thick, fleshy. Stems and branches terete, sulcate or angular, glabrous or young shoot and inflorescence pubescent. Leaves petiolate, rarely sessile; leaf blade ovate, elliptic, or lanceolate, apex acute or obtuse. Flowers pedicellate or sessile, in racemes, cymose panicles, or spikes, terminal or leaf-opposed. Tepals 5, persistent, spreading or reflexed, oblong to ovate, herbaceous or membranous, apex obtuse. Stamens 6-33, inserted at base of tepals; filaments subulate or linear, free or connate at base, included or exserted. Ovary subglobose, carpels 5-16, free or connate. Styles subulate. Fruit a fleshy berry, oblate. Seeds black, shiny, reniform, compressed; testa hard and fragile, smooth; tegument membranous.
About 25 species: nearly cosmopolitan, mostly native to South America, a few species in Africa and Asia; four species (one endemic, one introduced) in China.