216 CYPERACEAE (SEDGE FAMILY) 



Perigynla obscurely ribbed (158) C. irichocarpa, v. Detoeyt 



Perigynla prominently ribbed. 



Sheaths hairy (158) C. irichocarpa, v. arintata 



Sheaths glabrous (158) C. irichocarpa, v. imberbis 



bh. Perigynia thin and papery, usually more or less inflated ff. 



ff. Staminate spike solitary or none or the terminal only partly 

 staminate (rarely a very short secondary spike at the base 

 of the other) gg. 

 gg. Leaves Involute-filiform ; perigynla broadly conic-ovoid, 6-6 



mm. long 156. C. oHgosperma. 



gg. Leaves flat hh. 

 M. Perigynia obconic or broadly obovoid, truncate or abruptly 

 rounded above to long subulate beaks ; terminal spike 

 often mostly pistillate. 

 Perigynia longer than the scales. 

 Pistillate scales subulate-tipped or awned . . . 161. O. squarroaa. 



Pistillate scales blunt 162. C. typhinoidea, 



Perigynia shorter than the rough-awned scales . . . 168. C. Frankii. 

 hh. Perigynia from subulate to ovoid or globose, if abruptly 

 beaked the terminal spike staminate ii. 

 ii. Pistillate spikes oblong-cylindric or narrower jj. 

 Qj. Perigynia scarcely inflated, rigid, lance-subulate, slender- 

 stipitate, with prominent rigid crowded ribs, soon 

 retrorse. 

 Teeth of the perigynia nearly parallel .... 164. C. Pseudo-Oyperus. 

 Teeth of the perigynia strongly divergent . . . 165. C. cotnoaa. 

 ^. Perigynia inflated, if stipitate large and bladder-like kk,. 

 hk. Mature perigynia less than 12 mm. long II. 



II. Pistillate scales mostly with thin serrulate awns ; 



perigynia not falcate mm. 

 mm. Staminate scales with rough awns ; plants 

 caespitose. 

 Perigynia slightly inflated, narrowly conic ; 



achenes obovoid ....".. 166. C. hyateridna. 

 Perigynia with bladdery-inflated subglobose 

 bodies and abrupt beaks ; achenes narrowly 

 ellipsoid-ovoid. 

 Pistillate spikes 1.5-2 cm. thick ; perigynia 7-10 



mm. long 167. C. lurida. 



Pistillate spikes 1-1.3 cm. thick ; perigynia 5-7 



mm. long (167) C. lurida, v. gradlia. 



mm,. Staminate scales smooth, scarcely if at all awned ; 



plant loosely stoloniferous .... 168. C. Schweiniitdi. 

 U. Pistillate scales smooth, or only the lowest 



serrulate nn, 

 itn. Plant caespitose, forming tussocks ; perigynia 

 somewhat falcate. 

 Spikes mostly clustered and sessile at the tip of 

 the culms ; perigynia retrorse. 

 Perigynia 8-10 mm! long .... 169. C. reiroraa. 



Perigynia 5-6 mm. long . , . (169) C. reiroraa, v. Bobinaonii. 

 Spikes scattered, mostly long-peduncled. 



Perigynia wide-spreading or retrorse . (169) C. reiroraa, v. ffariii. 

 Perigynia ascending . . . (169) C. reiroraa, v. Macounii. 



nn. Plant not caespitose, the culms solitary from slen- 

 der rootstocks ; perigynia not falcate . . 170. C. Halei. 

 kk. Mature perigynia more than 12 mm. long. 



Achene rhomboid-ovoid, the angles prominently 



nipple-tipped 172. O. lupuUformia. 



Achene narrowly ellipsoid-ovoid, the angles scarcely 

 nipple-tipped. 

 Pistillate spikes mostly crowded, sessile or sub- 

 sessile 173. C. lupulina. 



Pistillate spikes mostly ped uncled, the lowermost 



remote (173) C. lupulina, v. pedunculata. 



ii. Pistillate spikes globose or subglobose oo. 

 00. Staminate scales prolonged into rough thin awns . 167. C. lurida. 



oo. Staminate scales smooth pp. 

 pp. Teeth of the beak erect or ascending qg. 

 qq. Mature perigynia green. 



Perigynia elongate-rhomboid, cuneate at base. 



Perigynia glabrous 174. C. Grayi. 



Perigynia hispidulous (174) C. Grayi, v. hispidula. 



Perigynia ovoid to narrowly conic, rounded at 

 . base. 



Perigynia ovoid-conic, half as broad as long . 175. C. iniumeacens. 

 Perigynia lance-conic, one fourth to one third 



as broad as long . . . (175) O. iniumtscena, v. FernaldU, 



qq,. Mature perigynia straw-colored. 



