Trees, deciduous, to 15 m tall. Bark dark brownish, nearly smooth; branches gray puberulent when young, later glabrous. Petiole 2.5-3.5 cm; leaf blade suborbicular or broadly ovate, 5-9 × 7-11 cm, subleathery, abaxially almost glabrous, adaxially glabrous, primary veins 9-13, secondary and higher order veins protruding, base shallowly to deeply cordate, apex bifid to 1/3, lobes rounded at apex. Inflorescence a raceme, few flowered, sometimes corymblike, axillary or terminal. Flower buds fusi­form, smooth, subsessile. Calyx open as a spathe into 2 lobes. Petals white, or with pink or purplish spots, obovate or oblan­ceolate, 4-5 cm, clawed. Fertile stamens 5; filaments ca. as long as petals, slender. Staminodes 1-5 and small, or ?absent. Ovary stalked, puberulent; style curved; stigma small. Legume linear, flat, 15-25 × 1.5-2 cm; valves woody. Seeds 10-15, com­pressed, suborbicular, ca. 10 mm in diam. Fl. Feb-May, fr. Mar-Jul. 2n = 28.

Tropical forests, also cultivated; 1000-1500 m. Native in S Yun­nan (Xishuangbanna); widely cultivated in S China [Cambodia, Laos, Myanmar, Thailand, Vietnam; widely cultivated in the tropics and sub­tropics].