Description from Flora of China
Carex melanantha C. A. Meyer var. moorcroftii (Falconer ex Boott) Kükenthal.
Rhizome creeping, thick. Culms 7-20 cm tall, trigonous, firm, clothed at base with brown sheaths disintegrating into fibers. Leaves shorter than culm, blades linear, 2-4 mm wide, flat, leathery, margins scabrous. Involucral bracts setaceous, shorter than inflorescence, sheathless. Spikes 4 or 5, approximate, lowest spike ± distant, densely many flowered; terminal spike male, oblong or cylindric, 1-1.8 cm; lateral spikes female, ovate or oblong, 0.7-1.8 cm, sessile or lowest with rather short peduncle. Female glumes purple, ovate-lanceolate, 5-6 mm, margins broadly white hyaline, apex acuminate. Utricles yellow-green, purple above, equaling or slightly shorter than glume, elliptic-obovate, trigonous, leathery, faintly veined, apex abruptly contracted into a short beak, orifice 2-toothed. Nutlets obovate, trigonous, 2-2.3 mm; stigmas 3. Fl. and fr. Jul-Sep.
Alpine meadows in thickets, grasslands, lakesides, plateaus; 3400-5700 m. Qinghai, W Sichuan, Xizang [NE India].