Eleocharis plicarhachis (Griseb.) Svenson

Eleocharis plicarhachis (Griseb.) Svenson, Rhodora 31 : 158. 1929.
Scirpus plicarhachis Griseb. Cat. PL Cub. 239. 1866.
Heleocharis elafa Bock. Vidensk. Meddel. 1871 : 151. 1872. (Maracaibo, an old colony in Brazil.)
Erect from an ascending spongy rootstock, often with slender, elongate rhizomes ; culms wiry, flexuous, striate and sulcate, 2.5-6 dm. high ; sheaths usually rigid, 4-8 cm. long, purplish or straw-colored, oblique at the summit; spikelets 1-2 cm. long, about 25-flowered, narrowly cylindric, acute ; scales loose, 3.5 mm. long, linear, obtuse, striate, with an obvious midrib ; style bifid; stamens 3; achene biconvex, 2 mm. long (including the beak), light brown, orbicular to obovate, with about 12 longitudinal rows of quadrate cells with upraised edges, narrowed at the summit and surmounted by a turgid annulus-elevation from which rises the deep-brown or black, lanceolate style-base ; bristles 6, exceeding the achene, coarse, flat, with strong, scattered teeth.
Type locality: Pinar del Rio, Cuba (C Wright 3372).
Distribution: Cuba; Mexico; Panama; British Guiana; Colombia; Brazil; Peru; Paraguay ; Argentina.