Description from Flora of China
Fimbristylis unicolor Ohwi & T. Koyama.
Annuals. Rhizomes absent. Culms tufted, 3-20 cm tall, 3-angled, striate, glabrous, with ca. 2 leaves at base. Leaves longer than culm; sheath rust-colored, 1-3.5 cm, adaxially membranous, mouth obliquely split; ligule ciliate, apex truncate; leaf blade 1-3 mm wide but apically attenuate, flat, glabrous, apex acute. Involucral bracts 2 or 3(or 4), leaflike, longer to shorter than inflorescence; bractlets subulate, broad at basal part, margin membranous. Inflorescence a simple, compound, or decompound anthela, 1-5 cm in diam.; rays 2-4, 0.5-3 cm. Spikelets solitary, narrowly oblong, narrowly ellipsoid, or rarely ovoid, 3-8 × 1-1.5 mm, with 8-10 or more flowers, apex obtuse to subacute. Glumes yellowish green to pale brown, ovate to ovate-lanceolate, ca. 2 mm (including mucro), 3-veined forming an abaxial green keel, margin broadly hyaline. Stamen 1; anther oblong, ca. 0.5 mm, 1/5-1/4 as long as filament, apex apiculate. Style basally inflated to conic; stigmas 2, ca. 1/2 as long as style. Nutlet pale yellow, ellipsoid-obovoid, obovoid, or ellipsoid, less than 1 mm, flat-convex, with transversely oblong reticulation but not verruculose. Fl. and fr. Aug-Nov.
● Cultivated fields, on rocks, marshes, riversides; 100-2000 m. Anhui, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Sichuan, SE Yunnan, Zhejiang.