CYPERACEAE, 223' 



Perigynia ascending, appressed or somewhat spreading when old, not radiating. 

 Perigynia ovate, oval, oblong or elliptic. 



Bracts short, scale-like or none, the lowest occasionally longer than its spike. 

 Spikes distinctly separated or the upper close together. 



Heads silvery green or nearly white. 177. C. canescens. 



Heads brown or brownish. 



Spikes few-flowered, 4-6 mm. long; perigynia less than 2 mm. long, 

 the beak manifest. 178. C. brunnescens. 



Spikes dense, many-flowered ; perigynia about 2 mm. long, the 

 beak very short. 179. C. Norvegica. 



Spikes densely clustered at the top of the culm, or the lower separated. 

 Spikes green or greenish brown. 



Spikes several in an ovoid cluster ; perigynia ovate, rough-beaked. 



180. C. arcta. 

 Spikes only 2-4; perigynia elliptic, beakless. 181. C. tenuiflora. 

 Spikes dark brown; arctic species. 

 Culms slender, stiff, erect. 



Leaves involute ; scales about equalling the perigynia. 



182. C. Heleonastes. 

 Leaves flat ; scales shorter than the perigyni' 1 . 



183. C. lagopina. 

 Culms weak, spreading or reclining. 184. C, glareosa. 



Bracts brktie-form, much elongated, much exceeding the 2-4 oblong nerved 

 perigynia. 185. C. trisperma. 



Perigynia lanceolate or ovate-lanceolate. 



Perigynia nerveless ; spikes oblong or subglobose. 186. C. Dewey ana. 



Perigynia strongly several-nerved ; spikes narrowly oblong-cylindric. 



187. C. bromoides. 



174. Carex sterilis Willd. Little Prickly Sedge. (I. F. f. 844.) Culms 

 slender, 2-4.5 dm. * a ^' rou gh> at least above. Leaves 1-2 mm. wide, shorter than 

 the culm; spikes 3-5, subglobose or short-oblong, about 5 mm. thick; staminate 

 flowers usually numerous at the bottom of the upper spike, or whole spikes occa- 

 sionally staminate, or plants rarely quite dioecious; perigynia pale, lanceolate, com- 

 pressed, spreading or reflexed when old, 3 mm. long, I mm. wide, several-nerved 

 on both faces, tapering into a sharp-edged 2 -toothed rough beak more than one- 

 half as long as the body; scales ovate, shorter than the perigynia. In moist soil, 

 Newf. to Br. Col., Fla., La., Colo, and Cal. Variable. May-July. 



Carex sterilis cephaldntha Bailey. Stouter, sometimes 5 dm. tall. Spikes 4-8, 

 contiguous or separated; flowers more numerous; perigynia rather larger; spikes very 

 bristly. Range nearly that of the species; perhaps merely a stout form. 



175. Carex Atlantica Bailey. Eastern Sedge. (I. F. f. 845.) Similar to 

 large forms of the preceding, but stouter; culms rough above, 3-7 dm. tall. Leaves 

 2-3 mm. wide, stiff, flat, or in drying somewhat involute ; spikes 4-7, subglobose or 

 short-cylindric, nearly 6 mm. in diameter; perigynia broadly ovate, flat, sharp- 

 margined, 2-3 mm. long, strongly several-nerved on the outer face, few-nerved on 

 the inner, spreading or reflexed at maturity, abruptly tipped with a stout rough 

 2-toothed beak about one-third as long as the body; scales shorter than the peri- 

 gynia. In swamps, Newf. to Fla. June-July. 



176. Carex interior Bailey. Inland Sedge. (I. F. f. 846.) Similar to 

 C. sterilis ; culms slender, wiry, 2-6 dm. tall. Leaves about 1 mm. wide, shorter 

 than the culm; spikes 2-4. nearly globular, 4 mm. in diameter; perigynia ovate or 

 ovate-lanceolate, 2 mm. long or less, faintly few-nerved on the outer face, nearly 

 nerveless on the inner, thickened, spreading or reflexed when old, tapering into a 

 nearly smooth 2-toothed beak one-third to one-half as long as the body; scales ovate, 

 shorter than the perigynia. Wet soil, Me. to Minn., Fla. and Kans. May-July. 



Carex interior capillicea Bailey. Leaves about 0.5 mm. wide ; perigynia ovate, 

 cordate, strongly nerved. Mass. to N. J. and Penn. 



177. Carex canescens L. Silvery Sedge. (I. F. f. 847.) Pale green and 

 somewhat glaucous ; culms slender, 2.5-6 dm. tall. Leaves flat, 1-2 mm. wide, 

 shorter than the culm ; spikes 4-9, short-oblong or subglobose, sessile, 5-10 mm. 

 long ; perigynia oval or ovate-oval, silvery green or nearly white, faintly few- 

 nerved, blunt-edged, rather less than 2 mm. long, rough above, with a minute 



