Description from Flora of China
Schoenus compressus Linnaeus, Sp. Pl. 1: 43. 1753; Blysmopsis compressus (Linnaeus) Oteng-Yeboah; Nomochloa compressa (Linnaeus) Beetle; Scirpus compressus (Linnaeus) Persoon.
Rhizomes 1-1.5 cm × 1.5-2 mm. Culms 9-30 cm tall, 3-angled, clothed at base with black bladeless leaf sheaths. Cauline leaves usually shorter than culm; sheath brown to rust-colored, mouth obliquely truncate, apex acuminate; ligule very short; leaf blade linear, flat, 1-3.5 mm wide, membranous. Involucral bract leaflike, slightly shorter or longer than inflorescence. Inflorescences consisting of 3-12 spikelets arranged in a simple distichous spike, oblong to obovoid, 1-2.2 × 0.4-0.9 cm. Spikelets ovoid to narrowly ovoid, 5-7 mm, 5-8-flowered. Glumes subdistichous, oblong-ovate, ca. 5 mm, membranous, 7-veined, apex obtuse. Perianth bristles 6, as long as nutlet, slightly flexuose at base, retrorsely scabrous. Stamens 3; anthers oblong, ca. 2 mm. Stigmas 2, as long as nutlet. Nutlet brown, obovoid, ca. 2 mm, plano-convex. Fl. and fr. Jul-Sep. 2n = 44, 79.
Swampy meadows, valleys, wet places; 500-5000 m. Qinghai, Shanxi (Lüliang Shan), Xinjiang, Xizang [Afghanistan, Bhutan, N India, Kashmir, Kazakhstan, Kyrgyzstan, Nepal, Pakistan, Russia, Tajikistan, Turkmenistan, Uzbekistan; N Africa, SW Asia, Europe].