Description from Flora of China
Shrubs or small trees, rarely subshrubs or herbs, erect or rarely climbing, deciduous or evergreen. Branchlets usually 4-angled when young. Leaves simple, opposite or rarely whorled. Inflorescences loosely cymose or capitate, in terminal or rarely axillary paniculate thyrses. Calyx campanulate or cup-shaped, ca. 5-dentate or deeply 5-lobed. Corolla with a slender tube; lobes 5, spreading. Stamens 4, ± exserted. Ovary 4-locular; ovules pendulous or laterally attached. Style with 2 acute stigmatic lobes. Fruiting calyx ± inflated. Fruit a drupe with 4 1-seeded pyrenes, sometimes separating into 2 2-loculed or 4 1-locular mericarps.
About 400 species: mostly tropical and subtropical, few in temperate Asia, Africa, and America; 34 species in China.