Perennials. Rhizomes long, short, or almost absent. Culms tufted, (10-)20-70 cm tall, flatly 3- or 4-angled, striate, sometimes apically winged, with many leaves at base. Leaves shorter than culm; sheath bilaterally compressed, abaxially membranous and rust-colored, adaxially keeled, mouth obliquely split and ciliate; ligule very short, ciliate; leaf blade 1-5 mm wide, flat, thickly papery, margin apically finely serrulate, apex acute. Involucral bracts 2-4, suberect, much shorter than inflorescence; bractlets setaceous, broader at base. Inflorescence a simple, compound, or decompound anthela, 7.5-10.5 × 4-7 cm; rays 3 or 4, 1-7 cm, compressed, scabrid. Spikelets many per inflorescence, solitary, oblong, ovoid, or narrowly ovoid, 5-9 × 1.2-2 mm, 5-13-flowered, apex acute. Glumes brown, ovate, ca. 3 mm, 1-veined forming an abaxial yellowish green keel excurrent into a mucro, apex acute. Stamens 3; anthers oblong, 1 mm or longer, ca. 1/4 as long as filament, apex acute. Ovary oblong, 3-sided; style 3-sided, glabrous, basally inflated to conic; stigmas 3, ± as long as style. Nutlet white or yellowish white, obovoid to broadly obovoid, ca. 1.5 mm, obtusely 3-sided, with transverse oblong reticulation. Fl. and fr. Jun-Oct.

Wet places in valleys, grasslands, streamsides, open fields, slopes, ditches, swampy places, along ravines; 100-3000 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, S Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shandong, Sichuan, Taiwan, SE Xizang, Yunnan, Zhejiang [Bhutan, India, Indonesia, Japan, Korea, Malaysia, Nepal, Pakistan, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; tropical Africa, SW Asia (Yemen), N Australia, Central and South America, Indian Ocean islands, Pacific islands].