Description from Flora of China
Mezonevron hymenocarpum Wight & Arnott ex Prain, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 66: 233, 472. 1897.
Climbers. Branches sparsely yellowish pubescent, with scattered, yellowish brown, recurved prickles. Leaves alternate; rachis 20-30 cm; pinnae 8-10 pairs, opposite; rachis of pinnae and leaves yellowish pubescent; petiolules short, with opposite, recurved prickles with stipules scalelike, ca. 0.5 mm; leaflets 5 or 6 pairs, abaxially yellowish green, adaxially deep green, oblong, 1.5-2 × ca. 1 cm, membranous, both surfaces yellowish pubescent, base broadly cuneate, apex obtuse-rounded. Racemes or panicles axillary or terminal, 30-50 cm. Pedicels 1-1.5 cm; bracts yellowish brown, lanceolate, densely yellowish pubescent, apex long acuminate. Receptacle discoid. Sepals 5, outside yellowish pubescent, lowest one cucullate, others oblong. Petals yellow, upper one orbicular, clawed, lateral 2 smaller, lowermost one folded and raised. Stamens 10; filaments thickened at lower part, densely brown villous, unequal, curved; anthers elliptic. Ovary smooth, 5-7-ovuled; style gradually inflated toward lower part; stigma praemorse. Legume compressed, thin, falcate, 10-15 × ca. 2.5 cm when ripe, winged along ventral suture, wing ca. 1 cm wide. Seeds 5-7, compressed, narrowly ovoid. Fl. Sep-Oct, fr. Dec-Feb.
Open forests, humid places; 300-800 m. W Guangxi (Baise), Yunnan [Bangladesh, Cambodia, India (Andaman Islands), Indonesia, Laos, Myanmar, Philippines, Sri Lanka, Thailand, Vietnam].