CYPERACEAE 183 



slender, retrorsely barbed, longer than the achene and tubercle : stigmas 2 : achenes obovoid, 

 like those of ^. ochreata, but twice as large, 3-4 times the length of the conic acute tubercle. 

 In wet soil, Maine to southern Ontario, Pennsylvania, and South Carolina. Summer and fall. 



9. Eleocharis maculosa (Vahl) R. Br. Perennial by slender rootstocks. Scapes 

 tufted, 1-3.5 dm. long, slender : spikelet ovoid, 5-12 mm. long, rather blunt, dense, purple- 

 brown : scales ovate or oblong-ovate, scarious-raargined, rather persistent : perianth-bristles 

 7-8, retrorsely scabrous, brown or rusty, as long as the achene : stigmas 2 : achenes obovoid, 

 about 1 mm. long, chestnut-brown, shining, the tubercle abruptly pointed, pale. 



In wet ground, Texas. Also in Central and South America. Spring to fall. 



10. Eleocharis capillicea Kunth. Annual, diminutive. Scapes tufted, capillary, 

 2-5 cm. long, sligntly 4-angled : spikelet linear-cylindric, 2-3 mm. long, with 1-4 achenes, 

 deep brown or reddish : scales few, nearly oblong or oblong-lanceolate, the 2 lower mostly 

 including the spikelet : perianth-bristles 4-6, about as long as the achene, retrorsely sca- 

 brous : stigmas 2 ; achenes lenticular, about 0.5 mm. long, exclusive of the slender conic 

 tubercle, brown. 



About pine-land ponds and in wet sand, North Carolina to Florida. Also in Central and South 

 America. Spring to fall. 



11. Eleocharis atropurpiirea ( Eetz) Kunth. Annual with fibrous roots. Scapes 

 tufted, very slender, 2-9 cm. high : upper sheath 1-toothed : spikelet ovoid, many-flowered, 

 subacute, 3-4 mm. long, 2 mm. in diameter, or less : scales minute, ovate-oblong, persist- 

 ent, purple-brown except the midvein and very narrow scarious margins : perianth-bristles 

 2-4, fragile, pale, minutely downwardly hispid, about as long as the achene : stigmas 2 : 

 achenes jet black, shining, 0.5 mm. long, smooth, lenticular ; tubercle conic, minute, de- 

 pressed but rather acute, constricted at the base. 



In moist soil. Iowa. Nebraska and eastern Colorado to Central America, east to Florida ; widely 

 distributed in tropical America. Summer and fall. 



12. Eleocharis capitata (L. ) R. Br. Annual with fibrous roots. Scapes densely 

 tufted, nearly terete, almost filiform, 0.5-2.5 dm. tall : upper sheath 1-toothed : spikelet 

 ovoid, obtuse, much thicker than the scape, 3-5 mm. long, 2-3 mm. thick, many-flowered : 

 scales broadly ovate, obtuse, firm, brown except the greenish midvein, narrowly scarious- 

 margined, persistent : perianth-bristles 5-8, slender, downwardly hispid, as long as the 

 achene : stigmas 2 : achenes obovoid, jet black, smooth, shining, 1 mm. long ; tubercle de- 

 pressed, apiculate, constricted at the base, very much shorter than the achene. 



In moist soil, Maryland to Indiana, Florida and Texas. Also in the tropics. Summer and fall. 



13. Eleocharis bicolor Chapm. Annual, pale green. Scapes tufted, filiform, 0.3-2 

 dm. long, sometimes procumbent, 4-angled : spikelet ovoid, 2-3 mm. long, rather blunt, 

 8-12-flowered : scales ovate, obtuse, thin, loosely imbricated, with whitish margins and 

 keel : perianth-bristles 3, fugacious : achenes lenticular, obovoid, 0.5 mm. long, papillose, 

 about twice as long as the bristles ; tubercle broadly conic, about ^ as long as the body of 

 the achene. 



In sandy soil, near the coast, Florida. Summer. 



14. Eleocharis obtiisa Schult. Annual with fibrous roots. Scapes tufted, relatively 

 stout, rather deep green, nearly terete, mostly erect, 0.5-5 dm. tall : upper sheath 1- 

 toothed : spikelet ovoid or oblong-ovoid, obtuse, many-flowered, 3-13 mm. long, 3-5 mm. 

 in diameter : scales thin, obovate, oblong-obovate or oblong-orbicular, obtuse, brown, each 

 with a broad green midvein and scarious margins : perianth-bristles 6-8, deciduous, usually 

 longer than the achene : stigmas 2 : achenes pale brown, shining, lenticular, obovoid-ob- 

 long, smooth, 1 mm. long or more; tubercle deltoid, acute, compressed, scarcely con- 

 stricted at the base, about I as long as the achene. 



In wet soil, New Brunswick to Ontario, British Columbia, Florida, Texas and Oregon. — A form 

 with more slender generally decumbent or spreading scapes, smaller fewer-flowered spikelets with 

 more spreading scales and a smaller achene, is E. obtusa jejuna Fernald. Summer and fall. 



15. Eleocharis Engelmdnnii Steud. Annual, quite similar to the next preceding 



species, but scapes commonly taller, sometimes 5 dm. high. Upper sheath obliquely truncate 



or 1-toothed : spikelet cylindric, obtuse or rather acute, 4-16 mm. long, 2-3 mm. in diameter, 



many-flowered : scales pale brown with a green midvein and narrow scarious margins, ovate, 



obtuse, deciduous : perianth-bristles about 6, not longer than the achene or very short or 



wanting : stigmas 2 : achenes obovoid or cuneate-obovoid, fully 1 mm, long, brown, smooth, 



lenticular ; tubercle broad, low, covering the top of the achene, less than ^ its length. 



In wet soil, Massachusetts to Virginia, Indiana, Arkansas, Texas and California.— The form with- 

 out perianth-bristles, or mere rudiments, and generally stouter scapes, is E. Engelmnnnii dctonsaA. Gray. 

 Summer and fall. 



16. Eleocharis lanceol^ta Fernald. Annual, bright green. Scapes tufted, slender 

 or nearly filiform, 1-2.5 dm. tall : spikelet lanceolate in outline, 5-9 cm. long, about 2 or 

 3 mm. thick, rather acute : scales pale, hyaline except green ribs, acute, rather appressed : 



