Description from Flora of China
Crotalaria incana subsp. purpurascens (Lamarck) Milne-Redhead; C. purpurascens Lamarck; C. schimperi A. Richard.
Herbs or shrublets, to 1 m tall. Stems brownish yellow spreading pubescent. Stipules acicular, 2-3 mm, tardily caducous. Leaves 3-foliolate; petiole 3-5 cm; petiolules 1-3 mm; leaflet blades elliptic-obovate, obovate, or suborbicular, 2-4 × 1-2 cm, terminal one larger than lateral ones, thin, abaxially pubescent to nearly glabrous, adaxially glabrous, secondary veins 6-10 on each side of midvein, secondary and tertiary veins abaxially distinct and adaxially inconspicuous, base rounded to broadly cuneate, apex obtuse and mucronate. Racemes terminal or leaf-opposed, 10-20 cm, 5-15-flowered; bracts 1-10 mm, caducous. Pedicel 3-4 mm; bracteoles inserted at base of calyx tube, similar to bracts, 2-3 mm. Calyx subcampanulate, 6-8 mm, 5-lobed, pubescent; lobes lanceolate, longer than tube. Corolla yellow, exserted beyond calyx; standard elliptic, 8-10 mm, base with appendages, apically usually pilose; wings oblong, 8-10 mm; keel ± as long as wings, abruptly rounded below middle, beak well developed and incurved. Legume clavate, 2-3 × 0.7-1 cm, apically slightly oblique, 20-30-seeded, densely rusty pilose; stipe ca. 2 mm. Fl. Oct-Dec, fr. Jan-Feb.
Sparse grasslands, along trails; below 100-2000 m. Cultivated or naturalized in Anhui, Guangdong, Guangxi, Jiangsu, Taiwan, Yunnan, and Zhejiang [pantropical; origin obscure].