CYPERACEAE. I J I 



gins; bristles 3 or 4, -.fragile, downwardly hispid, equalling or longer than the 

 achene, fugacious or perhaps sometimes wanting; stamens 3; style 3 -cleft; achene 

 3-angled, obpyramidal, black, smooth; tubercle depressed, covering the summit 01 

 the achene, light brown, pointed in the middle. In wet sandy soil, E. Mass. and 

 R. I. to Fla., near the coast. Also in W. Ind. July-Sept. 



17. Eleocharis albida Torr. White Spike-rush. (I. F. f. 593.) Annual; 

 roots fibrous; culms very slender, tufted, nearly terete, striate, erect, 0. 1-0.2 m. 

 tall. Upper sheath very oblique and toothed on one side; spikelet ovoid-globose 

 or oblong, obtuse, 4-8 mm. long, 3-4 mm. 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, Md. to Fla., Tex. and Mex., near the coast. 

 June -Aug. 



18. Eleocharis tricostata Torr. Three-ribbed Spike-rush. (I. F. f. 594.) 

 Perennial by short rootstocks; culms very slender, erect, compressed, striate, 

 0.3-0.6 m. tall. Upper sheath obliquely truncate, toothed on one side; spikelet 

 oblong, becoming oblong-cylindric, obtuse, many-flowered, 10-18 mm. long, 2- 

 3 mm. in diameter; scales ovate, thin, deciduous, obtuse, brown with a green mid- 

 vein 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,- S. N. Y. to Fla. July-Sept. 



19. Eleocharis tenuis (Willd.) Schultes. Slender Spike-rush. (I. F. f. 

 595.) Perennial by rootstocks; culms tufted, filiform, mostly erect, 4-angled with 

 concave sides, 0.2-0.4 m - tall. Upper sheath obliquely truncate, toothed on one 

 side; spikelet narrowly oblong, mostly acute, many-flowered, thicker than the 

 culm, 6-10 mm. long, about 2 mm. 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 Isl. to Ont. and Manitoba, south to Fla. and Tex. The 

 achenes are more or less persistent on the rachis of the spikelet after the fall of the 

 scales. May-July. 



20. Eleocharis acuminata (Muhl.) Nees. Flat-stemmed Spike-rush. 

 (I. F. f. 596.) Perennial by stout rootstocks, similar to the preceding species but 

 stouter; culms flattened, striate, slender but rather stiff, tufted, 0.2-0.5 m - tall. 

 Upper sheath truncate, sometimes slightly 1 -toothed; spikelet ovoid or oblong, 

 obtuse, thicker than the culm, many -flowered, 6-12 mm. 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, obtusely 3-angled, light yellowish brown, papillose, much longer than the 

 iepressed-conic acute tubercle. In wet soil, Anticosti to Manitoba, south to Ga., 

 La., Mo. and Neb. Achenes persistent on the rachis as in E. tenuis. June-Aug. 



21. Eleocharis intermedia (Muhl.) Schultes. Matted Spike-rush. (I. F. f. 

 597.) Annual; roots fibrous; culms filiform, densely tufted, diffusely reclining or 

 iscending, usually matted, grooved, 10-30 cm. long. Upper sheath obliquely 

 iruncate, toothed on one side; spikelet ovoid-oblong, acute, 8-20-flowered, thicker 

 Jian the culm; scales oblong-lanceolate, obtuse or the upper subacute, light purple- 

 Drown with a green midvein, tardily deciduous or the lower one persistent; bristles 

 persistent, downwardly barbed, longer than the achene and tubercle; stamens 3; 

 tyle 3-cleft; achene 3-angled, obovoid, light brown, finely reticulated; tubercle 

 onic-subulate, very acute, slightly constricted at the base, one-fourth to one-half 

 is long as the achene. In marshes, Ont. to Minn., south to N. J., Ohio, 111. and 

 owa. July-Sept. 



22. Eleocharis rostellata Torr. Beaked Spike-rush. (I. F. f. 598.) Per- 

 nnial by a short caudex; culms slender, wiry, the fertile erect or ascending, the 

 terile reclining and rooting at the summit, grooved, 0.3 -1. 5 m. long. Upper 

 'heath truncate; spikelet oblong, narrowed at both ends, thicker than the culm, 



