Eleocharis bonariensis Nees

Eleocharis bonariensis Nees, Jour, Bot. Hook
2 : 398. 1840.
Chaetocyperus bonariensis Nees in Mart. Fl. Bras. 2^: 96. 1842. Chaetocyperus obtusatus Nees in Mart. Fl. Bras. 2^: 94. 1842. (Brazil.) Heleocharis striatula Desv. in C. Gay, Hist. Chile Bot. 6: 173. 1853. (Chile.) Heleocharis oxyneura Durieu, Bull. Soc. Bot. Fr. 2: 609. 1855. (France.) Eleocharis amphibia Durieu; Cuigneau, Act. Soc. Linn. Bordeaux 21: 487. 1858. (France.) Eleocharis aciculariformis Greenman, Proc. Am. Acad. 34: 566. 1899. (Mexico.) Heleocharis acicularis subsp. B. H. bonariensis Osten, Anal. Mus. Hist. Nat. Montevideo II. 3 : 173. 1931.
Rootstocks creeping, 1-1.5 mm. thick; culms fascicled, usually flattened, somewhat rigid, 1.5-4 dm. high, about 0.5 mm. wide, bright green or yellowish, striate and sulcate; sheaths yellow or brown, often reddish at the base, the firm apex obtuse, elongated and spreading; spikelets lanceolate, 4-8 mm. long, the lowest scale about half the length of the spikelet ; scales ovate-lanceolate, obtuse, green with reddish sides; style trifid; stamens 3, anthers 1.5 mm. long; achene elliptic to narrowly obovate, 1-1.3 mm. long, with many longitudinal ribs and about 50-60 trabeculae in each longitudinal series ; style-base small, conic, one-third as wide as the achene; bristles 3 or 4, white, sharply toothed, equaling the achene or somewhat shorter.
Type locality : Argentina.
Distribution: Mexico; southern South America; vicinity of Bordeaux, France, where undoubtedly introduced.