216 



CYPERACEAE (SEDGE FAMILY) 



Perigynia obscurely ribbed (158) C. trichocarpa, v. Deweyi 



Perigynia prominently ribbed. 



Sheaths hairy (158) C. trichocarpa, \. aristata. 



Sheaths glabrous (158) (7. trichocarpa, v. imberbis. 



bb. Perigynia thin and papery, usually more or less inflated 

 ff. Staminate spike solitary or non 



none or the terminal only partly 



staminate (rarely a very short secondary spike at the base 

 of the other) gg. 

 gg. Leaves involute-filiform ; perigynia broadly conic-ovoid, 5-6 



mm. long .......... 156. C. oligosperma. 



gg. Leaves flat M. 



Kh. 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 

 Pistillate scales blunt ....... 



Perigynia shorter than the rough-awned scales . 

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



beaked the terminal spike staminate ii. 

 ii. Pistillate spikes oblong-cylindric or narrower jj. 

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

 stipitate, with prominent rigid crowded ribs, soon 

 retrorse. 

 Teeth of the perigynia nearly parallel .... 



Teeth of the perigynia strongly divergent . 

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

 kk. 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 ....'.. 



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 ....... 



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



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



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



plant loosely stoloniferous .... 168. C. Schweinitzii. 



II. Pistillate scales ' smooth, or only the lowest 



serrulate nn. 

 nn. 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. retrorsa. 



Perigynia 5-6 mm. long . . . (169) C. retrorsa, v. Robinsonii. 

 Spikes scattered, mostly long-peduncled. 



Perigynia wide-spreading or retrorse . (169) C. retrorsa, v. Hartii. 

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

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



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



161. <7. squarrosa. 



162. C. typhinoides. 



163. C. Frankii. 



164. C. Pseudo-Cyperus. 



165. C. comosa. 



166. C. hystericina. 



167. C. lurida. 



kk. Mature perigynia more than 12 mm. long. 



Achene rhomboid-ovoid, the angles prominently 

 nipple-tipped ....... 



Achene narrowly ellipsoid-ovoid, the angles scarcely 



nipple-tipped. 

 Pistillate spikes 



172. C. lupuliformis. 



mostly crowded, sessile or sub- 

 sessile ........ 



Pistillate spikes mostly peduncled, the lowermost 



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



ii. Pistillate spikes globose or subglobose oo. 

 oo. Staminate scales prolonged into rough thin awns 

 oo. Staminate scales smooth pp. 

 pp. Teeth of the beak erect or ascending qq. 

 qq. Mature perigynia green. 



Perigynia elongate-rhomboid, cuneate at base. 

 Perigynia glabrous ..... 



Perigynia hispidulous . 

 Perigynia ovoid to narrowly conic, rounded at 



base. 



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

 Perigynia lance-conic, one fourth to one third 



as broad as long . . . (175) C. intumescens, v. Fernaldii. 

 qq. Mature perigynia straw-colored. 



173. C. lupulina. 



167. C. lurida. 



174. C. Grayi. 

 (174) C. Grayi, v. hispidula. 



