ORDER 155. CYPERACEJ5. 737 



5 E. tricostata Torr. Culm filiform, flattened, striate, 1 to 2f high; spike cylin- 

 dric-oblong, dense-flowered, 6 to 9" long; glumes ovate, obtuse, rusty brown, with 

 a broad, scarious margin and a green midvein ; bristles ; ach. obovate, with 3 

 prominent, thick angles, roughish, brown, crowned with a whitish, minute tuber- 

 cle ; style 3-cleft. Wet places, N. J. to Fla. 



6 E. Robbinaii Oakas. Culms clustered, 9 25' high, rigid, sharply triangular, 

 pale green, several of them fruitless; sheath truncate ; spike 3 12" long, scarcely 

 thicker than the stem, placed 2 5'' betow its apex ; glumes 3 9, linear-lanceo- 

 late, acute, finally brownish; bristles 6, twice longer than the acheniuin ; ach. 1' 

 long, pale brown ; tubercle closely sessile. Ponds and ditches, N. H. and Mass. 

 (Ricard). Very distinct. In water a part of the stems are floating and as fine 

 as hairs. Jl. 



7 E. capitata Brown. Culm filiform, furrowed, angular, 4' to 6', in tufts ; spike 

 globular-ovoid, 2" long, greenish white; glumes 12 to 15, oblong, obtuse; 

 bristles G, some of them a little exceeding the ach., which is broadly obovate. 

 lens-shaped, black, shining, crowned with a minute, depressed tubercle ; style 2- 

 cleft. Wet places, Ga., Fla. to La. 



8 E. albida Torr. Culm filiform, terete, striate, sulcate on one side, 8 to 12' : 

 spike ovoid, acute, 2 to 3'' long; glumes 20 to 30, whitish, ovate, rather acute : 

 bristles 6, brown, longer than the chestnut-colored, smooth, broad-ovate ach. : 

 iubercle small, acute ; style 3-cleft. Wet, sandy places, Ga., Fla. to La. Known 

 at sight by its whitish heads. Sheaths very short. 



9 E. olivacea Torr. Culms ccespitous, 2 4' high, slender, subcompressed, eul- 

 cate, soft: spike ovate, acutish, 2 3" long, 20 30-flowered ; glumes ovate, ob- 

 tuse, reddish-brown, with scarious edges and a green midvein, the lowest largest ; 

 bristles 6 ; sty. 2-cleft ; ach. broadly obovate, smooth, of a dull, blackish-olive 

 color when ripe. Sands, generally partly submersed. Providence, R. I. (Olney) 

 Mass, to Ga. 



10 E. tennis Schultes. Culm almosi filiform, quadrangular, the sides sulcate, 

 8 15', with a long, purple sheath at base ; spike 2 to 3" long, elliptic-oval, acute 

 at each end ; glumes dark purple, ovate, obuse, the lower ones larger and empty : 

 ova. roundish, tapering below, invested with 2 or 3 or setae. Common in wet 

 places, Can. and U. S. Jn., Jl 



11 E. obtusa Schultes. Culm sulcate, subterete, 6 15' high; spike ovoid, very 

 obtuse, often nearly globous ; glumes 60 to 100, round, dark brown, with whitish 

 margins ; ach. obovate, compressed, smooth, brown, invested with 6 seta3 as long 

 as the glumes, and crowned with a broad, flat tubercle. Shallow waters. Can. 

 and U. S., common. Jl. 



12 E. tuberculosa R. Br. Culm columnar, striate, 12' high, leafless, sheathed 

 at base; spike ovate-lanceolate, acutish, glumes very obtuse, loose; ach. somewhat 

 triquetrous, not larger than the sagittate tubercle with which it is crowned ; bristles 

 6, as long as the "tubercle. Sandy swamps, N. Eng. to Flor. and La. Remark- 

 able for its large tubercle. Jl. 



13 E. simplex Torr. Culm acutely 3-angled (terete Torr.), filiform, striate, 12 to 

 18'; spike ovoid, acutish; scales ovate, obtuse, whitish with a brown center; 

 bristles 6, rigid, longer than the ach., which is broad-obovate, furrowed length- 

 wise, olive-green, crowned with a large, distinct, conic-beaked tubercle ; style 3- 

 cleft. Wet places, N. Car. to Fla. and La 



14 E. rostellata Torr. Cfclm 15 20', clustered, angular and sulcate. slender, 

 almost filiform, rigid ; sheaths obliquely truncate, the lowest blackish at summit : 

 spike lance-ovate, acute, 3 4'' long ; glumes 12-^-20, lance-ovate, smooth, light 

 brown, edge scarious ; bristles 4 to 6, longer than the smooth ach., which is bi- 

 convex, olive-broiun, with a confluent, acuminate tubercle, shorter than the 6 

 bristles. R, I. (Olney), N. T. (SartweU), to Mich. 



15 E. melanocarpa Torr. Culm compressed, furrowed, slender, almost filiform, 

 wiry, 12 18' high; sheaths truncate; spike lance-oblong, rather acute. 4 6' ; n 

 length, 20 40-flowered ; glumes ovate, obtuse, brownish, with scarious margins 

 and a prominent, yellowish midvein ; bristles 3, purple ; ach. obovate-turbinate. 

 blackish ; tubercle broad, flat, pointed in the center. Providence, R. I. (Olney). 



16 E. compressa Sullivant. Culm 12 18' high, csespitous, much compressed, 



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