CYPERACEAE. 225 



185. Carex trisperma Dewey. Three-fruited Sedge. (I. F. f. 855.) 

 Bright green ; culms filiform, weak, usually reclining or spreading, 3-7 dm. long. 

 Leaves flaccid, flat, about I mm. wide, shorter than the culm ; spikes 2 or 3, 

 only 2-4-flowered, widely separated, the lowest subtended by a bristle-form bract 

 1-8 cm. long ; perigynia oblong, green, 3-4 mm. long, very finely many -nerved, 

 narrowed at both ends and tipped with a very short nearly entire beak ; scales 

 ovate or ovate-lanceolate, acute, somewhat shorter than the perigynia. In swamps 

 and wet woods, Newf. to Manitoba. Md., Ohio, Mich, and Neb. June-Aug. 



186. Carex Deweyana Schwein. Dewey's Sedge. (I. F. f. 856.) Pale 

 green ; culms slender, spreading, 2-6 dm. long. Leaves 2-3 mm. wide, flat, soft, 

 shorter than the culm ; bracts bristle-form, the lower commonly elongated ; spikes 

 3-6, oblong or subglobose, few-flowered, about 5 mm. in diameter, sessile, separated 

 or the upper contiguous ; perigynia lanceolate or ovate-lanceolate, thin, nerveless, 

 4-5 mm. long, the inner face flat, the tapering rough strongly 2 -toothed beak at 

 least one-half as long as the body; scales nearly white, cuspidate or acute, equalling 

 the perigynia, or shorter. In dry woods, N. S. to Manitoba, Ore., Conn., Penn., 

 Iowa. X. Mex. and Utah. May-July. 



187. Carex bromoides Schk. Brome-like Sedge. (I. F. f. 857.) Bright 

 green ; culms slender, roughish above, 2-6 dm. long. Leaves 2 mm. wide or less, 

 flat, soft; bracts subulate or bristle-form, the lowest commonly elongated; spikes 3-7, 

 narrowly oblong-cylindric, 8-16 mm. long, erect or ascending, mostly close 

 together, the staminate flowers either basal, basal and terminal, or forming whole 

 spikes, the plant occasionally quite dioecious ; perigynia linear-lanceolate, pale, 

 strongly several-nerved, 4-5 mm. long, the inner face flat, the tapering rough 

 2 -toothed beak at least one-half as long as the body; scales oblong-lanceolate, green, 

 acute or acuminate, shorter than the perigynia. In bogs and swamps, N. S. to 

 Ont., Mich.. Fla. and La. June-Aug. 



Perigynia lanceolate or ovate-lanceolate, 2-5 times as long as wide. 



Top of the culm nodding ; arctic and northwestern species. 188. C. pratensis. 

 Culms strictly erect, mostly stiff. 



Perigynia nerveless, broadly winged ; northwestern species. 



189. C. xerantica. 

 Perigynia several-nerved on both faces. 



Perigynia broadly winged ; staminate flowers intermixed with the pistillate. 



190. C. siccata. 

 Perigynia narrowly winged ; staminate flowers all basal. 



Spikes 1-2.5 cm - long; perigynia about 8 mm. long. 



191. C. Muskingumensis. 

 Spikes 0.4-1.6 cm. long; perigynia 4-6 mm. long. 



Spikes oblong or oval; perigynia ascending or erect. 



Spikes green-brown, blunt. 192. C. tribuloides. 



Spikes bright brown, pointed ; perigynia lanceolate. 



193. C. scop aria. 

 Spikes rather dark brown, blunt ; perigynia ovate-lanceolate. 



194. C. leporina. 

 Spikes subglobose; perigynia spreading, at least when old. 



195. C. cristatella. 

 Perigynia ovate, not more than twice as long as wide (longer [ n SO me forms of no. 198). 



Perigynia narrowly winged above; heads greenish brown. 196. C. adust a. 

 Perigynia broadly wing-margined. 



Perigynia spreading or ascending. 



Spikes silvery green. 197. C. foenea. 



Spikes yellowish brown or greenish. 198. C. straminea. 



Perigynia erect or appressed. 



Heads silvery green or nearly white; sea beach species. 



199. C. silicea. 

 Heads brown-green; meadow or marsh species. 200. C. tenera. 

 Perigynia orbicular, very broadly ovate or somewhat obovate, sometimes wider than long. 

 Heads green-brown. 



Perigynia spreading or ascending; achene sessile. 201. C. festucacea. 



Perigynia erect, 4-5 mm. broad; achene short-stalked. 202. C. alata. 

 Heads silvery green, yellowish or whitish. 



Perigynium-wing firm; achene sessile. 203. C. albolutescens. 



Perigynium-wing membranous: achene stalked. 204. C. Bicknellii. 



Perigynia narrowly linear-lanceolate, tapering into a subulate beak 2-3 times as long a? 

 the body. Cyperoideae. 205. C. sychnocephala. 



