C YPERA CEA E. 1 69 



ties 6-8, slender, retrorsely barbed, longer than the achene and tubercle ; achene 

 obovoid, similar to that of the preceding species but twice as large. 3-4 times the 

 length of the conic acute tubercle. In wet soil, Me. to S. Ont. and Penn., south to 

 S. Car., mostly near the coast. Aug. -Sept. 



6. Eleocharis atropurpurea (Retz) Kunth. Purple Spike-rush. (I. F. f. 

 582.) Annual ; roots fibrous ; culms 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, persistent, purple-brown with 

 green midvein and very narrow scarious margins ; stamens 2 or 3 style 2-3 -cleft ; 

 bristles 2-4, fragile, white, minutely downwardly hispid, about as long as the 

 achene; achene jet black, shining, 0.5 mm. long, smooth, lenticular; tubercle conic, 

 minute, depressed but rather acute, constricted at the base. In moist soil, Iowa, 

 Neb. and E. Colo, to Cent. Am., east to Fla. ; widely distributed in tropical 

 America. July-Sept. 



7. Eleocharis capitata (L.) R. Br. Capitate Spike-rush. (I. F. f. 583.) 

 Annual; roots fibrous; culms densely tufted, nearly terete, almost filiform, 5-25 cm. 

 tall. Upper sheath I -toothed; spikelet ovoid, obtuse, much thicker than the culm, 

 3-5 mm. long, 2-3 mm. thick, many-flowered ; scales broadly ovate, obtuse, firm, 

 pale or dark brown with a greenish midvein, narrowly scarious-margined, per- 

 sistent ; stamens mostly 2 ; style 2-cleft ; bristles 5-8, slender, downwardly hispid, 

 as long as the achene ; achene obovate, jet black, smooth, shining, nearly 1 mm. 

 long; tubercle depressed, apiculate, constricted at the base, very much shorter than 

 the achene. In moist soil, Md. to Fla., west to Ind. and Tex. Widely distributed 

 in tropical regions. July-Sept. 



8. Eleocharis ovata (Roth) R. & S. Ovoid Spike-rush. (I. F. f. 584.) An- 

 nual ; roots fibrous ; culms tufted, slender or filiform, rather deep green, nearly 

 terete, mostly erect, 5-40 cm. tall. Upper sheath I -toothed ; spikelet ovoid or 

 oblong, obtuse, many-flowered, 4-10 mm. long, 2-3 mm. in diameter ; scales thin, 

 oblong-orbicular, very obtuse, brown with a green midvein and scarious margins; 

 bristles 6-8 (sometimes fewer or wanting), deciduous, usually longer than the 

 achene ; stamens 2 or 3 ; style 2-3 -cleft ; achene pale brown, shining, lenticular, 

 obovate-oblong, smooth, I mm. long or more ; tubercle deltoid, acute, compressed, 

 scarcely constricted at the base, about one-fourth as long as the achene and nar- 

 rower. In wet soil. N. B. to Ont. and Br. Col. south to Fla., Ore., Neb. and Tex. 

 Also in Europe. Variable. July-Sept. 



9. Eleocharis Engelmanni Steud. Engelmann's Spike-rush. (I. F. f. 

 585.) Annual, similar to the preceding species, but culms commonly taller, 

 sometimes 0.5 m. high. Upper sheath obliquely truncate or I -toothed ; spikelet 

 oblong-cylindric or ovoid-cylindric, obtuse or subacute, 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; style 2-cleft; bristles about 6, not longer 

 than the achene; achene broadly obovate, brown, smooth, lenticular; tubercle broad, 

 low, covering the top of the achene, less than one-fourth its length. In wet soil, 

 Mass. to Va., west to Ind., Ark., Tex. and Cal. July-Sept. 



10. Eleocharis palustris (L.) R. & S. Creeping Spike-rush. (I. F. f. 

 586.) Perennial by horizontal rootstocks; culms stout, terete or somewhat com- 

 pressed, striate, 0.3-1.6 m. tall. Basal sheaths brown, rarely bearing a short 

 blade, the upper one obliquely truncate; spikelet ovoid-cylindric, 6-25 mm. long, 

 3-4 mm. in diameter, many-flowered, thicker than the culm ; scales ovate-oblong 

 or ovate-lanceolate, purplish brown with scarious margin and a green midvein, or 

 pale green all over; bristles usually 4, slender, retrorsely barbed, longer than the 

 achene and tubercle, or sometimes wanting ; stamens 2-3 ; style 2-3 -cleft ; achene 

 lenticular, smooth, yellow, over I mm. long ; tubercle conic-triangular, constricted 

 at the base, flattened, one-fourth to one-half as long as the achene. In ponds, 

 swamps and marshes, Lab. to Br. Col., south to Fla., Tex. and Cal. Alio in 

 Europe and Asia. Aug. -Sept. 



Eleocharis palustris glauc^scens (Willd.) A. Gray. Culms slender or nearly fili- 

 form, 0.2-0.5 m - ta A \ spikelet oblong, 4-10 mm. long; achene smaller; tubercle narrower. 

 In wet meadows and marshes; range nearly of the type in N. Am. Perhaps a distinct 

 species. 



The so-called variety calva is a form without bristles. 



