Scirpus barbatus Rottbøll, Descr. Icon. Rar. Pl. 27. 1773; Bulbostylis disticha Ohwi & T. Koyama; Isolepis barbata (Rottbøll) R. Brown.

Rhizomes absent. Culms densely tufted, 0.6-3 cm tall, 0.5-0.8 mm thick, erect, smooth. Leaf sheath brownish, 0.5-2 cm, thinly membranous, glabrous, mouth white hyaline and with scattered long hairs; leaf blade filiform, 4-10 cm × 4-8 mm, abaxially glabrous or sometimes sparsely pilose, margin entire, apex acuminate. Involucral bracts 2 or 3, setaceous, 1-2.5 cm or ± short, very slender, abaxially glabrous or with scattered hairs. Inflorescences terminal, capitate, 5-12 mm thick, with 3-15 sessile spikelets. Spikelets narrowly ovoid, 3-6.5 × 1-1.5 mm, angular, 7-13-flowered, base obtuse to subrounded, apex acute. Glumes brownish to yellowish green turning eventually pale brownish, ovate to nearly broadly ovate, 1.5-2 × 1-1.5 mm, keeled, membranous, apically occasionally pubescent, margin ciliolate, apex with a recurved short awn. Stamens 1(or 2); anther oblong, apex acute. Style filiform; stigmas 3. Nutlet pale brown to yellowish, obovoid-globose, ca. 0.8 × 0.5-0.6 mm, 3-sided, obscurely tuberculate with transversely rectangular cells, apex rounded to emarginate; persistent style base depressed globose. Fl. and fr. Jun-Nov. 2n = 10.

This species is naturalized in North and South America.

Sandy beaches, sometimes beside cultivated fields; 100-2000 m. Anhui, Fujian, Guangdong, Guangxi, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Nei Mongol, Shandong, Taiwan, Zhejiang [Bhutan, Cambodia, India, Indonesia, Japan, Kashmir, Korea, Laos, Nepal, Pakistan, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; N Africa, Atlantic Ocean islands, Australia, Indian Ocean islands].