Description from Flora of China
Shrubs or small trees. Leaf blade granular or subgranular in texture, glabrous, pubescent, or tomentose. Inflorescences leaf-opposed or extra-axillary and 1-flowered or fasciculate and several flowered. Flowers small, bisexual. Sepals 3, slightly smaller than petals, valvate. Petals 6, in 2 whorls, thick, sometimes outer and inner petals united at base forming a sympetalous corolla; outer petals small, valvate, spreading; inner petals larger than outer, sometimes connivent and erect, inside concave, base shortly clawed, margin adhering but later free, apically often incurved and valvate but occasionally imbricate. Stamens many; anther locules cuneate, extrorse; connectives apically broadly flat-topped to slightly concave. Carpels few to many; ovules 1 or 2 per carpel; styles very short; stigmas subcapitate to cuneate, grooved on top and down inner side. Fruit apocarpous; monocarps subsessile to stipitate, globose [or ovoid]. Seed often 1 per monocarp, rugose or pitted and with a circumferential ridge.
About 50 species: tropical Africa, tropical Asia, Oceania; one species in China.
(Authors: Li Bingtao (李秉滔 Li Ping-tao); Michael G. Gilbert)