17° FLORA. 



Eleocharis paliistris Watsoni Clarke. Culms stout, 15-25 cm. tall ; spike ovoid ; 

 scales dark purple-brown. Lab. and Pr. Edw. Isl- to Hudson Bay. 



11. Eleocharis acicularis (L.) R. & S. Needle Spike-rush. (I. F. f. 587.) 

 Perennial by filiform stolons or rootstocks; culms tufted, finely filiform or setaceous, 

 obscurely 4-angled and grooved, weak, erect or reclining, 5-20 cm. long. Sheaths 

 truncate ; spikelet compressed, narrowly ovate or linear-oblong, acute, broader than 

 the culm, 3-10-flowered, 3-6 mm. long, 1 mm. wide; scales oblong, obtuse or the 

 upper subacute, thin, pale green, usually with a narrow brown band on each side 

 of the mid vein, deciduous, many of them commonly sterile; bristles 3-4, fragile, 

 fugacious, shorter than the achene; stamens 3; style 3-cleft; achene obo void -oblong, 

 pale, obscurely 3 -angled with a rib on each angle and 6-9 lower intermediate ribs 

 connected by fine ridges; tubercle conic, acute, one-fourth as long as the achene. 

 In wet soil, throughout N. Am., except the extreme north. Also in Europe and 

 Asia. July-Sept. 



12. Eleocharis Wolfii A. Gray. Wolf's Spike-rush. (I. F. f. 588.) 

 Perennial by short rootstocks; culms slender, erect, flattened and 2-edged, 

 0.2-0.5 m - * a ^- Upper sheath oblique, scarious, hyaline-tipped; spikelet oblong 

 or ovoid-oblong, terete, acute, thicker than the culm, 4-6 mm. long, nearly 2 mm. 

 in diameter; scales ovate, obtuse or the upper acute, thin, pale green with purplish 

 brown bands, tardily deciduous; bristles none (or perhaps early deciduous); style 

 3-cleft; achene obovoid, obscurely 3-angled, longitudinally 9-ribbed, the ribs 

 transversely connected by minute ridges; tubercle depressed-conic, much shorter 

 than the achene. In wet meadows, 111., Minn, and Iowa. June-Aug. 



13. Eleocharis tortilis (Link) Schultes. Twisted Spike-rush. (I. F. f. 589.) 

 Annual; roots fibrous; culms tufted, filiform, sharply 3-angled, pale green, erect or 

 reclining, twisting when old, 0.3-0.4 m. long. Sheaths obliquely truncate, i-toothed; 

 spikelet ovoid or oblong, subacute, several-flowered, 4-6 mm. long, about 

 2mm. thick, much thicker than the culm; scales firm, pale, ovate, mostly obtuse; 

 bristles 4-6, rigid, retrorsely barbed, about equalling the achene and tubercle; 

 stamens 3; style 3-cleft ; achene obovoid, obscurely 3-angled, strongly reticulated, 

 longitudinally about 18-ribbed; tubercle cap-like or conic, truncate at the base, 

 one-fourth to one-half as long as the achene. In wet soil, near the coast, N. J. to 

 Fla. and Tex. July-Sept. 



14. Eleocharis tuberculosa (Michx.) R. & S. Large-tubercled Spike- 

 rush. (I. F. f. 590.) Annual ; culms tufted, slightly compressed, very slender, 

 rather stiff, striate, bright green, 0.2-0.5 m - ^ a ^- Upper sheath obliquely truncate 

 or 1 -toothed; spikelet ovoid, many-flowered, 6-12 mm. long, nearly 4 mm. in 

 diameter; scales broadly ovate, obtuse, pale greenish brown with a darker midvein, 

 broadly scarious-margined, firm, tardily deciduous; bristles 6, rigid, downwardly 

 or rarely upwardly barbed, about as long as the achene and tubercle; stamens 3; 

 style 3-cleft; achene obovoid, pale, trigonous, strongly reticulated, longitudinally 

 about 18-ribbed; tubercle cap-like or conic, nearly or quite as large as the achene. 

 In wet soil, near the coast, Mass. to. Penn., Fla. and Tex. July-Sept. 



15. Eleocharis Torreyana Boeckl. Torrey's Spike-rush. (I. F. f. 

 591.) Annual; culms finely filiform, densely tufted, somewhat 4-sided, erect or 

 reclining, often proliferous by developing secondary culms in the axils of the spike- 

 let, sometimes rooting at the summit, 5-20 cm. long. Upper sheath obliquely trun- 

 cate ; spikelet oblong, subacute, terete or nearly so, much thicker than the culm, 

 many-flowered, 3-5 mm. long; scales ovate, acute, brownish-red with a green 

 midvein and lighter margins, early deciduous except the lowest, which is commonly 

 larger than the others, persistent and bract-like; bristles 3-6, slender, shorter than 

 or equalling the achene; stamens 3; style 3-cleft; achene white, 3-angled, obovoid, 

 smooth, minute- tubercle conic-pyramidal, much shorter than the achene. In wet 

 sandy soil, S. N. J. to Fla. and Tex., mostly near the coast. June-Aug. The 

 similar E. microcarpa Torr. occurs only in the Gulf States and West Indies. 



16. Eleocharis melanocarpa Torr. Black-fruited Spike-rush. (I. F. f. 

 592.) Perennial by short rootstocks; culms flattened, striate, tufted, slender, erect, 

 0.2-0.5 in. tall. Upper sheath truncate, I-toothed; spikelet oblong or cylindric- 

 oblong, obtuse. 6-12 mm. long, 3-4 mm. in diameter, many-flowered, thicker than 

 the culm; scales ovate, obtuse, brown, with a lighter midvein and scarious mar 



