CYPEKACEAE (SEDGE FAMILY) 215 



q. Perigynia closely impressed-nerved ; scales rough- 

 awned. 



Sheaths pubescent 128. C. Hitchcockiana, 



Sheaths glabrous 129. C. oligocarpa. 



p. Perigynia oblong-ovoid to obovold or globose, rounded to 



thf sessile or abruptly short-stlpitate base . 

 U. Closely caespitose, not stoloniferous V. 



v. Culms 1-6 cm. high, more than twice exceeded by the 



leaves and bracts 180. C. katahdinenttt. 



V. Culms taller ; bracts proportionately shorter v>. 

 w. Uppermost bract slightly if at all overtopping the 



staminate spike; perigynin inipressea-nerved 181. C. conoidea. 

 tr. Uppermost bract much overtopping the staminate 

 spike (If rarely shorter, the perigynia with 

 prominent ribs) x. 

 3D. Perigynia impressed-nerved y. 

 y. Style jointed below the middle. 



Leaves thin and soft, slightly if at all glaucous. 

 Spikes borne principally in the upper axils. 

 Perigynia oblong. 

 Perigynia turgid, beakless, scarcely 



angled 182. C. gritea. 



Perigynia scarcely turgid, trigonous, 

 narrowed to a beak . . (182) C. gritea, v. rigida. 



Perigynia subglobose . . . (182) C. gritea, v. globota. 

 Spikes borne from the lowest as well as the 



upper axils .... (182) C. gritea, v. anguttifolia. 

 Leaves thick and firm, very glaucous . . 188. C. glaucodea. 

 y. Style jointless ; perigynia golden-brown . . 184. C. flaccotperma. 

 to. Perigynia with elevated ribs and short point or 



beak. 



Perigynia plump-ovoid to globose . . . 186. C. granular if. 

 Perigynia oblong .... (186) C. granularit, \. ffttleana. 

 it. Culms solitary, from slender stoloniferous base . . 186. C. Craicei. 

 O. Perigynia wide-spreading or squarrose, slender-beaked ; 

 spikes mostly toward the summit of the culm ; bracts 

 divergent z. 



z. Leaves involute ; perigynia spreading-ascending . . 187. C. extent a. 

 z. Leaves flat ; perigynia squarrose aa. 

 aa. Beak about as long as the body of the perigynium, often 



bent, at least in maturity. 



Staminate spike sessile or very short-stalked, some- 

 times pistillate at tip ; pistillate spikes mostly 

 contiguous. 

 Fruiting spikes 9-12 mm. thick, short-cylindric or 



globose ; beaks spreading in all directions . 188. C. flata. 

 Fruiting spikes 6.5-8 mm. thick, mostly short- 

 cylindric perigynia mostly wide-spreading and 



straightish (188) C. flata, v. rectirottra. 



Staminate spike usually peduncled ; pistillate mostly 



remote, the curved perigynia usually retrorse . (188) C. flava, v. elatior. 

 aa. Beak distinctly shorter than body of the perigynium, 

 straight or slightly bent, ascending or horizontally 

 spreading. 



Staminate spike usually peduncled ; pistillate scat- 

 tered 189. C. Oederi. 



Staminate spike usually sessile, often more or less 



pistillate; pistillate spikes mostly approximate (189) C. Oederi, v. pumiia. 

 P. Beak or tip of perigynium sharply bidentatf, the teeth acerote bb. 

 bb. Perigynia firm and tough, closely investing the achene cc. 

 cc. Tee'th less than 1 mm. long, erect dd. 

 dd. Perigynia pubescent. 



Leaves involute-filiform 151. C.filiformit. 



Leaves broad and flat. 



Scales mostly equaling the densely hairy perigynia . . 152. C. lanuginota. 

 Scales mostly shorter than the sparsely hairy perigynia 158. C. Houghtonii. 

 dd. Perigynia glabrous. 



Perigynia broadly ovoid 155. C. striata, v. brenit. 



Perigynia narrowly ovoid. 



Perigynia more than 5 mm. long, becoming lustrous. . 159. C. riparia. 

 Perigynia less than 5 mm. long, dull and minutely papillose 160. C. acutiformit. 

 cc. Teeth more" than 1 mm. long, divergent or recurved ee. 



ee. Scales of staminate spike hairy 157. C. hirta. 



ee. Scales of staminate spike glabrous. 

 Perigynia hairy. 



Perigynia ovoid, in slender cyllndric spikes . . . 158. C. trichocarpa. 

 Perigynia lance-subulate, in short-cylindric or ovoid 



spikes (158) C. trichocarpa, v. titrbinata 



Perigynia glabrous. 



