Description from Flora of China
Caoutchoua Gmelin; Siphonia Richard.
Trees, monoecious, with much milky latex. Leaves alternate, spirally arranged, or subopposite at apex of branches; stipules small, caducous; petiole long, glandular at apex; leaf blade palmately compound, usually 3-foliolate; leaflets entire, petiolulate. Inflorescence in axils of leaves or fallen leaves, many-flowered panicles of cymes, central flower of each cyme female, others male. Male flower: bud subglobose or ovate-globose; sepals 5-dentate or 5-lobed, lobes valvate; disk small, 5-lobed or dissected, rarely indehiscent; stamens 5-10; filaments connate into column longer than anthers; anthers sessile, in 1 or 2 series. Female flowers: sepals as in male; female disk dissected or obsolete; ovary 3-celled; ovules 1 per cell; styles usually absent; stigmas stout. Capsules large, usually 3-valved; epicarp subfleshy; endocarp woody. Seeds oblong-elliptic, maculate-striate; caruncle absent; cotyledon broad and flattened.
About ten species: Amazonian South America, one species widely cultivated throughout the tropics; one species (introduced) in China.
(Authors: Li Bingtao (李秉滔 Li Ping-tao); Gordon D. McPherson)