Description from Flora of China
Annuals. Roots fibrous. Culms tufted, 3-15 cm tall, flaccid, 3-angled, smooth, base with few leaves (often withered by flowering time). Leaves shorter than culm; leaf blade 1-2 mm wide, usually folded. Involucral bracts 2 or 3, linear, longer than inflorescence. Inflorescence a simple anthela; rays 2-6, mostly to 2 cm. Spikelets 5 to many, digitately arranged at apex of ray, linear, 4-12 × ca. 1.5 mm, 8-26-flowered; rachilla wingless. Glumes purplish red to brown on both surfaces, ± laxly imbricate, oblong, 1-1.5 mm, 3-veined, apex truncate and with a recurved (0.5-)0.6-1 mm awn. Stamens 3; anthers ellipsoid, ca. 0.1(-0.2) mm. Style (0.2-)0.4-0.6 mm; stigmas 3, 0.3-0.5 mm. Nutlet dark brown, oblong-obovoid to oblong, 0.5-0.6 mm, ca. 1/2 as long as subtending glume, 3-sided, with many tubercles. Fl. and fr. Jun-Sep(-Oct).
Sand at river margins, grasslands at water margins, seashores, along trails, wastelands, mountain slopes, forests, fields; near sea level to 2000 m. Anhui, Fujian, Guangdong, Guangxi, Hainan, Jiangsu, Jiangxi, Shandong, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bangladesh, Bhutan, India, Indonesia, Kashmir, Laos, Malaysia, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, Vietnam; Africa, Australia, Central, North, and South America, Indian Ocean islands, Madagascar].