Description from Flora of China
Shrubs or small trees. Branches terete or obtusely 4-sided, glabrous or pubescent. Leaves petiolate; leaf blade ovate to oblong, secondary veins 1 on each side of midvein, margin entire. Flowers 4- or 5-merous. Inflorescences terminal, cymose paniculate; bracts small, caducous. Hypanthium campanulate, pubescent or glabrous. Calyx lobes 3-8 or inconspicuous. Petals 4 or 5, white or purple. Stamens 8 or 10(or 12), equal; filaments short; anthers oblong or 3-sided, small, longitudinally dehiscent; connective decurrent and inflated, usually conic, 2-3 × as large as anthers or not appendaged. Ovary inferior, 2-5-celled, apex often truncate but without a crown; ovules with parietal placentation near base of ovary. Style short; stigma capitate. Capsule subglobular, enclosed by hypanthium; hypanthium subglobular, apical margin irregular. Seeds linear to linear-oblanceolate, small.
About 60 species: China, Malaysia, Philippines; Pacific islands; one species (endemic) in China.