Description from Flora of China
Rhizome short and thick, ligneous. Culms densely tufted, 10-50 cm tall, slender, obtusely trigonous, smooth, clothed with few red-brown and bladeless sheaths, rudimentary sheaths usually disintegrating into reticulate fibers. Leaves shorter or slightly longer than culm, blades 1-2 mm wide, scabrous and revolute on margins, sheathed. Involucral bracts leaflike, slender, longer than inflorescence, lower involucral bracts shortly sheathed, upper very shortly sheathed or almost not sheathed. Spikes 4-7, lowest spike inserted near base of culm or rather remote, remaining spikes congregated at top of culm; terminal spike male, narrowly cylindric or narrowly lanceolate, 1.5-4 cm, subsessile; lateral spikes female, sometimes with few male flowers at apex or branching bearing secondary spikes at base, female spikes oblong or oblong-cylindric, 0.8-2.5 cm, densely many flowered, lower spikes shortly pedunculate, upper subsessile. Female glumes yellowish brown, oblong or subovate, 2-3 mm, membranous, costate, apex acuminate. Utricles stramineous, sometimes brownish at base, obliquely patent, shorter than glume, broadly ovate or ovate, trigonous, 2-2.5 mm, membranous, densely white hispidulous, indistinctly veined, base abruptly contracted into a very short stipe, apex abruptly contracted into a short beak, orifice 2-toothed. Nutlets brown, tightly enveloped in utricle, obovate, broadly obovate, or subelliptic, trigonous, ca. 1.5 mm, base shortly stipitate, apex with torsional mucro; style base not thickened; stigmas 3. Fl. and fr. Jul-Aug.
Dense forests, riversides, mountain slopes; 2300-3500 m. Xizang, Yunnan [Bhutan, NE India, Kashmir, Nepal].