Description from Flora of China
Trees, producing kneelike pneumatophores. Trunk basally buttressed, often with a cone of stilt roots at base. Leaf scars showing evidence of 3 vascular bundles. Leaves entire. Inflorescences cymes, 1-5-flowered, pedunculate. Flowers generally nodding. Calyx accrescent, tube extending beyond ovary; lobes 8-14(-16), subulate-lanceolate. Petals as many as calyx lobes, usually 2-lobed, fringed with hairs and/or bristles. Stamens 2 × as many as petals, in unequal pairs opposite petals, each pair enclosed by inrolled petal margins; anthers introrse, dehiscing lengthwise. Ovary inferior, 2-4-loculed; ovules 2 per locule; style lobes 2-4. Fruit campanulate. Seed usually solitary, viviparous; hypocotyl terete or obscurely ribbed.
Six species: E Africa, SE Asia, N Australia, Indian Ocean islands, Pacific islands; three species in China.