Description from Flora of China
Trees or erect shrubs. Inflorescences axillary or superaxillary, fasciculate or cymose, 1-flowered. Flowers mostly bisexual. Pedicel slender, usually elongate. Torus elevated, usually long pubescent. Sepals 3, small, valvate, connate at base. Petals 6, in 2 whorls, with each whorl valvate; outer petals similar to sepals; inner petals large, erect, thin, base shallowly saccate and shortly clawed, margin initially cohering but readily free, apex usually revolute. Stamens many; connectives narrow and not concealing anther locules, apex subapiculate. Carpels many, oblong; ovules 1-8 per carpel; stigmas capitate, ovoid, or globose. Fruit apocarpous; monocarps many, subsessile to long stipitate, globose to ovoid. Seeds 1 to several per monocarp.
About 38 species: tropical and subtropical Asia and Australia; seven species (three endemic) in China.
(Authors: Li Bingtao (李秉滔 Li Ping-tao); Michael G. Gilbert)