Description from Flora of China
Rhizome short. Culms densely tufted, 25-70 cm tall, slender, trigonous, smooth. Leaves shorter than culm, blades (1.5-)2-3(-4.5) mm wide, flat, scabrous on both surfaces and margins, sheathed; sheaths usually split. Involucral bracts sheathed, lower 1 or 2 leaflike, upper blade setaceous, slightly scabrous; sheaths 5-20 mm, membranous part brown, slightly split. Spikes numerous, 3-6 in an involucral bract sheath, lower spikes usually branched, androgynous, male part shorter than female part, male part of terminal spike longer, narrowly oblong, 8-12 mm, female part loosely few flowered. Female glumes brown, broadly ovate or oblong-lanceolate, 1-2 mm, membranous, 1-costate, margins white hyaline and ± erose, apex acute or obtuse, muticous. Utricles reddish brown, suberect, longer than glume, elliptic, plano-convex, 2.5-3(-4) mm, membranous, glabrous, thinly 5-7-veined, base cuneate, shortly stipitate, apex abruptly narrowed to a medium-sized beak, orifice shortly 2-toothed. Nutlets yellowish, tightly enveloped, elliptic, plano-convex, ca. 1.5 mm; style base slightly thickened; stigmas 2, short. Fl. and fr. Aug-Oct.
● Forests, ditch sides, riversides, mountain slopes, rock crevices, grasslands; 1300-2200 m. Chongqing, Guizhou, Jiangxi, Shaanxi, Sichuan, Taiwan, Xizang, Yunnan.