CYPERACEAE. 185 



perianth-bristles 4-6, rigid, retrorsely barbed, about efjualling the achene and tubercle : 

 stigmas 3 : achenes obovoid, nearly 1.5 rum. long, obscurely 3-angled, strongly reticulated ; 

 tubercle cap-like or conic, truncate at the base, \—h as long as the achene. 

 In wet soil, near the coast, New Jerse\' to Florida and Texas. Summer and fall. 



25. Eleocharis tuberculosa (Michx. ) R. & S. Annual. Scapes tufted, slightly 



compressed, very slender, rather stiff, striate, bright green, 2-.5 dm. tall : upper sheath 



obliquely truncate or 1-toothed : spikelet ovoid to conic-ovoid, many-flowered, 6-12 mm. 



long, nearly 4 ram. in diameter: scales broadly ovate, obtuse, pale greenish brown with 



darker midveins, broadly scarious-margined, firm, tardily deciduous: ])erianth-bristles 6, 



rigid, downwardly or rarely upwardly barbed, about as long as the achene and tubercle : 



stigmas 3 : achenes obovoid, 1.-5 mm. long, pale, 3-angled, strongly reticulated ; tubercle 



cap-like or conic, as large as the achene or larger. 



In wet soil, mostly near the coast, Massachusetts to Pennsylvania, Florida and Texas. Summer 

 and fall. 



26. Eleocharis Torreyana Boeckl. Annual. Scapes filiform, densely tufted, some- 



wliat 4-sided, erect or reclining, sometimes proliferous by developing secondary scapes in 



the a.x;ils of the spikelet, sometimes rooting at the summit, 2-20 cm. long : upper sheath 



obliquely truncate : spikelet oblong, subacute, terete or nearly so, many-flowered, 3-6 



nim. long : scales ovate, acute, brownish red with green midveins and lighter margins, 



early deciduous except the lowest, which is commonly larger than the others, persistent 



and bract-like : perianth-bristles 3-6, slender, shorter than the achene or equalling it : 



stigmas 3: achenes white, 3-angled, obovoid, smooth, 0.7-0.8 mm. long, constricted at the 



base ; tubercle conic-pyramidal, minute. 



In wet sandy soil, southern New Jersey to Florida and Texas, mostly near the coast. Also in 

 Cuba. Spring and summer. 



27. Eleocharis microcdrpa Torr. Annual, bright green. Scapes tufted, finely fili- 

 form, or capillary, 5-20 cm. tall, smooth, barely constricted at the summit, spikelet ob- 

 long, 2-3 mm. long, few-flowered, acute : scales oblong to ovate, blunt or rather acute, 

 pale or with brownish patches on either side of the midrib : perianth -bristles 3-5, very 

 slender, about f as long as the achene : stigmas 3 : achenes grayish white, 3-angled, ob- 

 ovoid, 0.5-0.7 mm. long, smooth or nearly so ; tubercle minute, pointed. 



In wet soil, Florida to Louisiana. Also in Cuba. Spring to fall. 



28. Eleocharis prolifera Torr. Annual, sometimes aquatic, bright green. Scapes 

 numerous, tufted, filiform, diffuse, or floating, flattened, 1-6 dm. long, or rarely shorter : 

 spikes conic, 4-8 mm. long, rarely fruiting, acute, proliferous or rooting : scales oblong 

 or oval, whitish, obtuse, thin : perianth-bristles barbed, stout, variable in length : achenes 

 3 angled, obovoid, nearly 1 mm. long, surpassing the bristles ; tubercle deltoid, or depressed. 



In and about ponds and ditches, North Carolina to Florida and Lousiana. Spring to fall. 



29. Eleocharis Bald winii (Torr. ) Chapm. Perennial by slender rootstocks. Scapes 

 filiform, tufted, diffusely spreading, 0.5-2 dm. long, grooved : spikelet oblong, 4-6 mm. 

 long, flattened, 3-5-flo\vered, commonly rooting and proliferous : scales 2-ranked, 4-6, 

 lanceolate, blunt or acutish, delicately nerved : perianth-bristles 4-6, unequal : achenes 

 3-angled, oblong, 1 mm. long, as long as the longer bristles ; tubercle 3-angled, abruptly 

 subulate-tipped, about i as long as the body of the achene. 



In sandy swamps, Georgia and Florida. Spring to fall. 



30. Eleocharis melanocdrpa Torr. Perennial by short rootstocks. Scapes flat- 

 tened, striate, tufted, slender, erect, 2-5 dm. tall : upper sheath truncate, 1-toothed : spike- 

 let oblong or cylindric-oblong, obtuse, 6-12 mm. long, 3-4 mm. in diameter, many-flow- 

 ered, thicker than the scape : scales ovate, obtuse, brown, with lighter midveins and 

 scarious margins : perianth-bristles 3 or 4, fraffile, downwardly hispid, equalling or longer 

 than the achene, fugacious or perhaps sometimes wanting ; stigmas 3 : achenes 3-angled, 

 obpyramidal, fully 1 mm. long, black, smooth ; tubercle depressed, covering the summit 

 of the achene, light brown, pointed in the middle. 



In wet sandy soil, eastern Massachusetts and Rhode Island to Florida, near the coast. Also in the 

 West Indies. Summer and fall. 



31. Eleocharis dlbida Torr. Annual. Roots fibrous : scapes very slender, tufted, 

 nearly terete, striate, erect, 1-2 dm. 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 scape : scales pale green or nearly white, rather firm, ovate, 

 obtuse, deciduous : perianth-bristles about 6, downwardly barbed, persistent, as long as 

 the achene : stigmas 3 : achenes broadly obovoid, fully 1 mm. long, nearly black when 

 ripe, 3-angled, smooth ; tubercle ovoid-conic, contracted or truncate at the base, about I 

 as long as the achene. 



In wet soil, Maryland to Florida. Texas and Mexico, near the coast. Spring and summer.— £. al- 

 bida Berlandh^ri (Clarke) Britton, a variety native of southeastern Texas, is stouter, has longer spikelets 

 and the tubercle is more beak-like. 



