This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Eleocharis albida Torr. Ann. Lye. N. Y. 3: 304. 1836.
Annual, roots- fibrous, culms very slender, tufted, nearly terete, striate, erect, 4'-8' tall. Upper sheath very oblique and toothed on one side; spikelet ovoid-globose or oblong, obtuse, 2"-4" long, 1 1/2"-2" in diameter, many-flowered, thicker than the culm; scales pale green or nearly white, rather firm, ovate, obtuse, deciduous; bristles about 6, downwardly barbed, persistent, as long as the achene; stamens 3; style 3-cleft; achene broadly obovoid, nearly black when ripe, 3-angled, smooth; tubercle ovoid-conic, contracted or truncate at the base, about one-fourth as long as the achene.
In wet soil, Maryland to Florida, Texas and eastern Mexico, near the coast. Recorded from Jamaica. June-Aug.
Eleocharis tricostata Torr. Ann. Lye. N. Y. 3: 310. 1836.
Perennial by short rootstocks, culms very slender, erect, compressed, striate, 1°-2° tall. Upper sheath obliquely truncate, toothed on one side; spikelet oblong, becoming oblong-cylindric, obtuse, many-flowered, 5"-9" long, 1"-1 1/4" in diameter; scales ovate, thin, deciduous, obtuse, brown with a green midvein and scarious margins; bristles none; stamens 3; style 3-cleft; achene obovoid, 3-angled, brown, dull, papillose, strongly ribbed on each of its angles; tubercle conic, acute, light brown, constricted at the base, minute, very much shorter than the achene.
In wet soil, eastern Massachusetts to southern New York and Florida. July-Sept.
Perennial by rootstocks, culms tufted, filiform, mostly erect, 4-angled with concave sides, 8-16' tall. Upper sheath obliquely truncate, toothed on one side; spikelet narrowly oblong, mostly acute, many-flowered, thicker than the culm, 3,"-5" long, about 1" in diameter; scales thin, obovate or ovate-oblong, obtuse, the midvein greenish, the margins scarious; bristles 2-4, shorter than the achene, fugacious or wanting; achene obovoid, obtusely 3-angled, yellowish-brown, papillose; stamens 3; style 3-cleft; tubercle conic, short, acute.
In wet soil, Cape Breton Island to Ontario and Manitoba, south to Florida and Texas. The achenes are more or less persistent on the rachis of the spikelet after the fall of the scales. Poverty-grass. Kill-cow. May-July.
Eleocharis compressa Sulliv. Am. Journ. Sci. 42: 50. 1842.
Eleocharis acuminata Nees, Linnaea 9: 294. 1835.
Perennial by stout rootstocks, similar to the preceding species but stouter, culms flattened, striate, slender but rather stiff, tufted, 8'-2° tall. Upper sheath truncate, sometimes slightly 1-toothed; spikelet ovoid or oblong, obtuse, thicker than the culm, many-flowered, 3"-6" long; scales oblong or ovate-lanceolate, acute or the lower obtusish, purple-brown with a greenish mid-vein and hyaline white margins, deciduous; bristles 1-5, shorter than or equalling the achene, fugacious, or wanting; stamens 3; style 3-cleft, exserted; achene obovoid, very obtusely 3-angled, light yellowish brown, papillose, much longer than the depressed-conic acute tubercle.
In wet soil, Anticosti to Manitoba, Washington, Georgia, Louisiana, Missouri and Nebraska. Achenes persistent on the rachis as in E. tenuis. June-Aug.