Description from Flora of China
Trees, producing latex. Leaves spirally arranged, often closely clustered at end of branchlets; stipules small to very large, usually early deciduous; leaf blade leathery to almost leathery. Flowers solitary or clustered in axils, sometimes terminal, usually with a long pedicel. Sepals 4(--6) in 2 whorls, inner sepals often with margins membranous and ciliate, outer sepals usually hirsute. Corolla cylindrical, with hairs at throat; lobes (5--)8(--18), usually woolly pubescent between stamens, appendages absent. Stamens in 1 to 3 whorls, inserted in corolla throat and alternating with lobes, glabrous or tomentose, sessile or subsessile; staminodes absent. Ovary usually pubescent, 6--8(--12)-locular. Style subulate, persistent. Berry globose to ellipsoid, with enlarged persistent brown calyx, 1--4-seeded. Seed scar linear to oblong or elliptic.
About 100 species: Australia, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; two species in China.