Description from Flora of China
Annuals. Roots fibrous. Rhizomes absent. Culms 1-3 cm tall, half-terete, basally usually with 1 or 2 bladeless or bladed sheaths. Leaves shorter than culm; sheath brownish, short, scarious at 1 side; leaf blade ca. 2 mm wide, flat or folded, margin not scabrous. Involucral bracts 2, leaflike, shorter to slightly longer than inflorescence, adaxially ± blackish purple, base ± wide. Inflorescence a simple anthela to almost capitate; rays few, very short, each with a few spikelets densely arranged at apex. Spikelets oblong to linear-oblong, 3-7 × 1.2-1.8 mm, compressed, 8-22-flowered; rachilla wingless, with successive glumes ca. 0.7 mm apart. Glumes blackish purple but adaxially pale yellowish or green at middle, slightly densely imbricate, ovate-lanceolate, ca. 1 mm, membranous, conspicuously longitudinally striate, obscurely 3-veined, margin apically white hyaline and usually involute, apex muticous. Stamens 2; anthers oblong, apex rounded to truncate, muticous, and mucronate. Style short; stigmas 3, longer than style. Nutlet yellowish, ellipsoid, ca. 1 × 0.5 mm, as long as subtending glume, stipitate, apiculate, 3-sided, smooth. Fl. and fr. Oct.
● Sandy stream margins; 800-1500 m. Shanxi.