Description from Flora of China
Perennials. Roots few, fibrous. Rhizomes very short. Culms scattered, (5-)15-40 cm tall, slightly slender, stiff, obtusely 3-angled or sometimes nearly half-cylindric, smooth, with a few leaves basally. Leaves shorter than culm; sheath grayish brown, ± short; leaf blade 1-2 mm wide, usually folded, apical margin scabrous. Involucral bracts 3, leaflike, longer than inflorescence. Inflorescence a simple anthela; rays very short, rarely to 1.5 cm, with 7 to many spikelets clustered into a globose capitulum. Spikelets narrowly to very narrowly ovoid, 4.5-11 × 1.5-2.2 mm, 10-26-flowered; rachilla 4-angled, with trabeculae in both lateral sulculi. Glumes dark purplish red on both surfaces, slightly laxly imbricate, elliptic to ovate-elliptic, 1.8-2 mm, membranous, veins 3 and greenish yellow, keel inconspicuous, apex obtuse and muticous. Stamens 2; filaments ca. 1.2 mm; anthers linear, ca. 0.5 mm; connective barely prolonged beyond anthers. Style short; stigmas 2, slender. Nutlet dark grayish brown, oblong to obovoid-oblong, ca. 0.9 mm, 2/5-1/2 as long as subtending glume, compressed biconvex, densely puncticulate. Fl. and fr. Jun.
● Wet places at river and pond margins; 2000-3000 m. SW Sichuan, NW Yunnan.