Description from Flora of China
Trees. Leaves abruptly pinnate; stipules leaflike; leaflets 2-10 pairs, leathery. Flowers bisexual, in terminal panicles or racemes; bracts and bracteoles caducous, ovate. Calyx tube very short, with disk at base; lobes 4, valvate or margin narrowly imbricate, ± with soft bristles. Petal 1, rarely 2. Stamens 10: 9 shortly united into an oblique tube, upper stamen free and reduced to an antherless, slightly short staminode; anthers oblong, dorsifixed, opening lengthwise. Ovary 2-5-ovuled, shortly stalked; style filiform, circinate; stigma small. Legume compressed, usually orbicular or oblong, ± oblique, large, dehiscent, often shortly prickly on surface of valves, rarely without prickles. Seeds 1 or 2, black, shiny, with a large fleshy aril at base.
Between 18 and 20 species: WC Africa (Gabon) and mostly in SE Asia; two species (one endemic, one introduced) in China.
(Authors: Chen Dezhao (陈德昭 Chen Te-chao), Zhang Dianxiang (张奠湘); Ding Hou)