Description from Flora of China
Trees, deciduous, to 16 m tall; crown open. Branchlets angular; branchlet, leaf rachis, and inflorescence tomentose or pubescent. Stipules deciduous, linear-lanceolate, smaller than leaflets; pinnae 4-12 pairs, sometimes to 20 pairs in cultivated species; glands near base of petiole and leaf rachis of uppermost pinnae; leaflets 10-30 pairs, obliquely linear to oblong, 6-12 × 1-4 mm, main vein close to upper margin, base truncate, margin ciliate, apex apiculate. Panicles terminal. Flowers pink. Calyx tubiform, ca. 3 mm, pubescent. Corolla ca. 8 mm; lobes deltoid, ca. 1.5 mm. Filaments pink, ca. 2.5 cm. Legume strap-shaped, flat, 9-15 × 1.5-2.5 cm, glabrous. Fl. May-Jul, fr. Aug-Oct. 2n = 26*.
Widely cultivated in Anhui, Fujian, Gansu, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, ?Liaoning, ?Shaanxi, Shandong, Shanxi, Taiwan, Yunnan, Zhejiang [C, E, and SW Asia].