Description from Flora of China
Reichardia decapetala Roth, Nov. Pl. Sp. 212. 1821; Caesalpinia decapetala var. japonica (Siebold & Zuccarini) H. Ohashi; C. decapetala var. pubescens (Tang & F. T. Wang) P. C. Huang; C. japonica Siebold & Zuccarini; C. sepiaria Roxburgh; C. sepiaria var. japonica (Siebold & Zuccarini) Gagnepain; C. sepiaria var. pubescens Tang & F. T. Wang.
Climbers, with copious prickles. Bark dull red. Branches, rachis of leaves, and inflorescence with recurved prickles and pubescent. Leaves 20-30 cm; pinnae 3-10 pairs, opposite, with prickles in pairs at base; stipules obliquely ovate, apex acuminate, caducous; leaflets 8-12 pairs, oblong, 1-2.5 cm × 6-12 mm, membranous, both surfaces puberulent, glabrescent when old, both ends obtuse-rounded. Racemes terminal, 15-30 cm, with abundant flowers; rachis densely prickly. Pedicels 3-4 cm, hairy, jointed at apex so flowers easily fall off. Sepals 5, oblong, puberulent. Petals reflexed at anthesis, yellow, orbicular or obovate, 1-1.2 cm, membranous, base shortly clawed. Stamens subequal to petals in length; filaments compressed at base, lanate in lower part. Ovary glabrous. Legume chestnut-brown, shiny, oblong-ligulate, 6-12 × 2.5-3 cm, fragile-leathery, glabrous, dehiscent and thickened to a narrow wing along ventral suture when ripe, apex prolonged into a sharp beak. Seeds 6-9, brown, elliptic, ca. 11 × 6 mm. Fl. and fr. Apr-Oct. 2n = 22*, 24*.
The roots, stems, and legumes are used medicinally for relieving pain.
Among bushes on mountain slopes, ravines, plains, hills, by riversides; near sea level to 1800 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Bangladesh, Bhutan, India, Japan, Laos, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Thailand, Vietnam].