Scirpus uniglumis Link, Jahrb. Gewächsk. 1(3): 77. 1820; Eleocharis euuniglumis G. Zinserling; E. kuoi Y. D. Chen.

Perennials. Stolons long to short. Culms single or tufted, 10-15 cm tall, ca. 1 mm thick, few ribbed and longitudinally sulcate. Leaf sheaths 2 or 3, basally blood-red and apically yellowish green, 1-4 cm, mouth truncate to slightly obliquely truncate. Spikelet narrowly ovoid, ovoid, or oblong, 3-8 × 1.5-3 mm, 4-10-flowered. Basalmost glume empty, amplexicaul for whole of spikelet base; fertile glumes at first green then becoming brownish at middle and both edges purplish red, laxly imbricate, oblong-ovate to oblong-lanceolate, ca. 4 × 2 mm, margin apically becoming broadly hyaline, apex obtuse. Perianth bristles 4-6, longer than nutlet, slightly curved, outwardly spreading, densely retrorsely spinulose. Stigmas 2. Nutlet at first yellow then becoming brown, obovoid to broadly ovoid, 1.4-1.7 × ca. 1 mm, biconvex, ventral side conspicuously convex and dorsal side slightly convex, sometimes obtusely 3-sided, apex constricted and overlain by style base; persistent style base white, shallowly conic-ovoid, slightly elongate basally, nearly as long as wide, ca. 1/2 as long and ca. 1/2 as wide as nutlet, spongy, apex rounded to obtuse. Fl. and fr. Apr-Aug. 2n = 46, 60-88.

Lake banks, swamps, meadows, shallow water margins; 100-3300 m. Gansu, Hebei, Nei Mongol, Qinghai, Shaanxi, Shanxi, Xinjiang, Yunnan [Afghanistan, India, Kazakhstan, Kyrgyzstan, Mongolia, Pakistan, Russia, Uzbekistan; N Africa, SW Asia, Europe, North America].