Description from Flora of China
Perennials. Rhizomes short. Culms tufted, 10-60 cm tall, flatly and obtusely 3-angled, sometimes thick at base, with many leaves. Leaf blade 1-4 mm wide, thick, flat, extremely rigid, margin finely serrulate, apex acute. Involucral bracts 1-3, shorter than inflorescence. Inflorescence a simple or decompound anthela, headlike with a few short rays or open with several elongated rays. Spikelets numerous, solitary or clustered, oblong to ovoid, 3-6 × 1.5-2.5 mm, densely many flowered, apex obtuse. Glumes brown, ovate to broadly ovate, 1.2-2 mm, membranous, abaxially 3-veined, margin broadly hyaline, apex obtuse. Stamens 3; anthers linear. Style slender, not ciliate, basally slightly thickened; stigmas 2 or 3. Nutlet purplish black when mature, obovoid to broadly obovoid, 0.7-1 mm, 3-sided or biconvex, indistinctly verruculose and with square or transversely oblong reticulation but sometimes subsmooth. Fl. and fr. Jun-Oct.
Dry sandy places along roads, coastal rocky places, gravelly places along rivers, sandy seashores; near sea level to 400 m. Fujian, Guangdong, Guangxi, Hainan, Nansha Qundao, Taiwan, Zhejiang [India, Indonesia, Japan, Laos, Malaysia, Sri Lanka, Thailand, Vietnam; Africa, Australia].