Description from Flora of China
Carex bengalensis Roxburgh; C. cruciata subsp. rubrobrunnea (Ohwi) T. Koyama; C. cruciata var. rubrobrunnea Ohwi; C. hakkuensis Hayata; C. valida Nees.
Rhizome thick, woody, with stolons. Culms tufted, 40-90 × 0.3-0.5 cm, trigonous, smooth. Leaves basal and cauline, longer than culms, flat, 4-13 mm wide, scabrid abaxially, glabrous adaxially; persistent sheaths dark brown, fibriform. Involucral bracts leafy, longer than inflorescence branches, long sheathed. Panicle compound; inflorescence branches usually single, rarely binate, ovate-triangular, 4-15 × 3-6 cm; peduncles of inflorescence branches rigid, bluntly trigonous, lowest one 10-18 cm, upper ones gradually shorter, smooth; inflorescence axes trigonous, hairy; bractlets glumelike, ca. 1.5 mm, hairy abaxially. Spikes numerous, bisexual, androgynous, arising from several veined, abaxially hairy cladoprophylls, patent horizontally, 5-12 mm; male part of spike nearly as long as female part; male glumes pale brownish white with dense brown spots and short lines, lanceolate, ca. 2.5 mm, membranous, apex acuminate, mucronate; female glumes ovate, ca. 2 mm, membranous, 3-veined, apex obtuse, shortly awned. Utricles pale brownish white with brown spots and short lines, longer than glumes, elliptic, trigonous, inflated, 3-3.2 mm, smooth or upper part loosely hairy, with several raised veins, subsessile, apex attenuate into beak of medium length, beak ca. 1/3 length of utricle, hairy or glabrous laterally, orifice obliquely truncate. Nutlets dark brown at maturity, ovate-elliptic, trigonous, ca. 1.5 mm; style base thickened; stigmas 3.
Forest margins, grasslands, roadsides; 300-2500 m. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Jiangxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, India, Indonesia, Japan, Nepal, Thailand, Vietnam; Madagascar].