64. Homalanthus A. Jussieu, Euphorb. Gen. 50. 1824.
澳杨属 ao yang shu
Authors: Bingtao Li & Hans-Joachim (Hajo) Esser
Trees or shrubs, monoecious (sometimes one sex missing); latex white; indumentum absent [or consisting of multicellular, uniseriate, brownish hairs]. Apical buds enclosed by conspicuous large stipules. Leaves alternate; stipules caducous; petioles long, 2-glandular at apex or eglandular; leaf blade sometimes peltate, margin entire [to serrate], pinnately veined. Inflorescence terminal, elongate racemelike thyrses, unbranched. Flowers unisexual, apetalous, without disk. Male flowers 1-3(to many) per bract, pedicellate; calyx 1- or 2-lobed, free, bilaterally compressed; stamens 4-50; filaments nearly as long as anthers, free; anthers basifixed, extrorse, 2-thecate, longitudinally dehiscent; pistillode absent; receptacle flat to elevated. Female flowers usually 1 per bract, pedicellate; calyx 1-3-lobed, free, eglandular or glandular; ovary smooth, papillate to puberulent, with 2(or 3) locules; ovules 1 per locule; style short to distinct; stigmas 2(or 3), glandular below, apex often bifid. Capsule subglobose, regularly or irregularly dehiscent. Seeds 2(or 3) per fruit, reddish to brownish, flattened, partly to completely covered by a whitish arillode; testa crustaceous; cotyledon broad and flattened.
About 20-25 species: S Thailand through Malaysia to Australia, New Zealand, and the Pacific islands, and SE China to the Philippines, also widely cultivated; one species in China.