Description from Flora of China
Shrubs or small shrubs. Stems 4-sided or nearly terete, often squamose-strigose. Leaves opposite, petiolate; leaf blade pubescent on both surfaces, secondary veins 2 or 3(or 4) on each side of midvein, margin entire. Flowers terminal or on top of branches, solitary, clustered, or panicled, 5-merous, showy. Hypanthium globose-urceolate, pubescent or squamose strigose. Calyx lobes lanceolate to ovate, lobulate or not. Petals usually obovate, oblique. Stamens 10, whorls very unequal in length. Longer stamens with purple anthers; connective long extended at base, adaxially with 2 tubercles. Shorter stamens with yellow anthers; connective not extended but with 2 abaxial tubercles. Ovary half inferior, ovoid, 5-celled, apex with dense trichomes; placenta axile, sometimes fleshy in fruit. Style filiform, as long as petals. Fruit a capsule or sometimes berrylike, porose dehiscence or transverse dehiscence at middle, pubescent or squamosly strigose. Seeds numerous, small, cochleate, densely punctate.
The genus was revised by Meyer (Blumea 46: 351-398. 2001).
Twenty-two species: SE Asia, N Australia, Pacific islands; five species (one endemic) in China.