Description from Flora of China
Trees or shrubs, evergreen, without spines, often with aerial roots. Stem nodes swollen. Stipules interpetiolar, sheathing terminal bud, caducous. Leaves simple, opposite or distichous, petiolate; leaf blade leathery, usually glabrous, margin entire, serrulate near apex, or completely serrulate. Inflorescences axillary, dense cymes. Flowers bisexual, actinomorphic; hypanthium present [or absent]. Calyx lobes 4-16, inserted on rim of hypanthium, free or scarcely connate a base, valvate, persistent in fruit. Petals usually as many as sepals, free, usually caducous, margin entire, lacerate, or 2-cleft. Stamens twice as many as calyx lobes; anther locules 4 to many, dehiscing longitudinally or by an adaxial valve. Hypogynous disk present or absent. Ovary inferior or half-inferior; carpels 2-5(-20), 2-8-loculed; ovules usually 2 per locule, pendulous; style 1; stigma entire, capitate, or lobed. Fruit pulpy or leathery, indehiscent. Seeds 1 to few, viviparous; seedling (propagule) 7-80 cm when shed (except in Carallia and Pellacalyx).
Ko Wan-cheung. 1983. Rhizophoraceae. In: Fang Wen-pei & Chang Che-yung, eds., Fl. Reipubl. Popularis Sin. 52(2): 125-143.
About 17 genera and 120 species: tropics and subtropics; six genera and 13 species (three endemic) in China.
(Authors: Qin Haining (覃海宁); David E. Boufford)