Description from Flora of China
Trees. Leaves with 1 pair of leaflets; stipules caducous; leaflets paired, thickly leathery, entire, often translucent glandular punctate, with short petiolules or subsessile. Flowers white, in terminal panicles or corymbose panicles; bracts and bracteoles caducous, ovate or orbicular, concave. Calyx tubular, solid in lower part, expanded and campanulate or turbinate in upper part; lobes 4, thickly leathery, imbricate. Petals 3 or 5, clawed or sessile, subequal in size or lower 2 small and squamose. Stamens 10, all perfect, free; filaments glabrous or hairy at base; anthers oblong, dorsifixed, cells opening lengthwise. Ovary shortly stalked, stalk adnate to calyx tube, glabrous or hairy, few ovuled; style filiform; stigma terminal, small. Legume drupelike, obliquely obovoid or oblong, thickly leathery or woody, rough and tuberculate, not dehiscent. Seeds few, of various shapes; testa hard, bony, without endosperm and aril; cotyledons thickened, fleshy; radicle short, straight.
About 26 species: tropical America and Africa; two species (both introduced) in China.
(Authors: Chen Dezhao (陈德昭 Chen Te-chao), Zhang Dianxiang (张奠湘); Kai Larsen, Supee Saksuwan Larsen)