黑叶木蓝 hei ye mu lan

Indigofera atropurpurea Buchanan-Hamilton ex Horne­mann var. nigrescens E. Pottinger & Prain; I. mekongensis Jesson.

Shrubs, erect, 1-2 m tall. Stems reddish brown; young branches green, striate, with appressed brown medifixed sym­metrically 2-branched trichomes. Stipules linear, 5-8 mm. Leaves 8-18 cm, 11-23-foliolate; petiole and rachis with sparse appressed medifixed trichomes; petiole 2-2.5 cm; rachis terete or slightly flattened, adaxially grooved; leaflet blades opposite, elliptic to obovate-elliptic, 1.5-2.5 × 0.7-1.3 cm, papery, both surfaces with sparse appressed medifixed trichomes, abaxially usually becoming dark or black or with black spots when dry, base broadly cuneate to rounded, apex obtuse and mucronate. Racemes ca. 19 cm, densely flowered; peduncle ca. 2 cm; bracts linear, 5-7(-9) mm, abaxially with brown medifixed trichomes. Pedicel 1-1.5 mm, with brown medifixed trichomes. Calyx 3-5 mm, with appressed brown and white medifixed trichomes; tube 2.5-3 mm; teeth triangular, most abaxial one ca. 1 mm. Corolla red to purple; standard obovate, 6.5-7 × ca. 4 mm, outside with appressed brown and white medifixed tri­chomes, inside basally hairy, base clawed, apex obtuse; wings 5.5-6 mm, margin ciliate; keel as long as wings, outside api­cally hairy, margin ciliate, spur ca. 1 mm. Stamens 4-5 mm; anthers ovoid-globose, base with a few trichomes. Ovary gla­brous, with 8 or 9 ovules. Legume cylindric, 1.7-2.8 cm, with sparse appressed medifixed trichomes, apex obtuse; endocarp blotched. Seeds 7 or 8 per legume, reddish brown, ovoid, ca. 2.5 mm. Fl. Jun-Sep, fr. Sep-Oct.

Hills, scrub, sparse forests, sunny grasslands, fields, river beaches; 500-2500 m. Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Shaanxi, Sichuan, Taiwan, SE Xizang, Yunnan, Zhejiang [India, Indonesia, Laos, Myanmar, Philippines, Thailand, S Vietnam].