Description from Flora of China
Rhizome short. Culms densely tufted, 10-30(-50) cm tall, slender, subrigid, obtusely trigonous, smooth, bearing many leaves at lower part. Leaves shorter than culm, blades 2-2.5 mm wide, flat, rather soft, smooth, slightly scabrous distally, sheaths short. Lower involucral bracts leaflike, upper involucral bracts setaceous, 5-15 mm, sheathed. Spikes 3-6, single in an involucral bract sheath, lower remote, longest space up to 6 cm, upper approximate; terminal spike male, oblong-lanceolate, 6-10 mm; lateral spikes female, cylindric or oblong, 8-18 mm, loosely (6-)8-10(-12)-flowered; peduncles slender, usually pendulous. Female glumes brownish yellow or stramineous, obovate or subelliptic, ca. 2 mm, membranous, 1-veined, early deciduous, apex rounded, muticous. Utricles yellow-green or brown at maturity, obliquely patent, longer than glume, ovate-fusiform, obovate-fusiform, or subelliptic, obtusely trigonous, 2-3 mm, membranous, shiny, nerveless, base abruptly constricted into a short stipe, apex abruptly narrowed to a very short beak not up to 0.5 mm, orifice obliquely truncate, white hyaline on margins. Nutlets brown, subloosely enveloped, broadly obovate, trigonous, ca. 1.5 mm, base estipitate; style base slightly thickened; stigmas 3. Fl. and fr. Jun-Aug.
Thickets on mountain slopes, grasslands, riversides, lakeshores, wet places in ravines; 1100-3200 m. Gansu, Hebei, Nei Mongol, Qinghai, Shanxi, Sichuan, Xinjiang, Xizang [Japan, Korea, Russia (European part, Siberia)].