CYPERACEAE (SEDGE FAMILY) 



Pistillate spikes 5-8 mm. thick 

 Scales cuspidate . 



(66) C. aguatilis, v. elatior. 

 (66) C. aqiiatilis, v. cuspidata. 

 (66) C. aguatilis, v. virescens. 



Scales hidden by the perigynia 

 /. Culms low ; leaves mostly basal, smooth ; basal off- 



shoots chiefly repent ...... 67. C. rigida. 



H. Perigynia elongate, with an empty twisted tip . . 68. C. torta. 

 G. Perigynia nerved. 



Caespitose, not stoloniferous ; green central portion 



of the scale about as broad as the darker margins . 69. C. lenticularis. 

 Stoloniferous ; green midrib of the purple or blackish 



scale very slender ....... 70. C. Goodenowii. 



f. Culms numerous in stools ; lower sheaths fibrillose. 



Perigynia elliptic, tapering about equally to base and apex. 

 Pistillate spikes dense, mostly full at 



71. C. stricta. 



(71) C. stricta, v. decora. 



72. C. aurea. 



73. C. bicolor. 



base ; scales blunt, 



slightly if at all exceeding the perigynia. 

 Pistillate spikes 2-7 cm. long ..... 



Pistillate spikes 0.5-1.5 cm. long .... (71) C. stricta, v. curtissima. 



Pistillate spikes rather loose, long-attenuate at base ; 



scales acutish ....... (71) C. stricta, v. anguxtata. 



Perigynia obovate or orbicular, shorter than the attenuate 



scales 

 E. Perigynia plump, subterete. 



Mature perigynia fleshy, pyriform or subglobose, orange or 

 brownish, glabrous ........ 



Mature perigynia not fleshy, ellipsoid, slender-stipitate, 

 white, pulverulent ........ 



B. Perigynia lustrous. 

 Perigynia nerved. 



Leaves flat ; bracts ascending ....... 180. C. Grahami. 



Leaves soon involute ; bracts divergent ..... 181. C. rotundata. 



Perigynia nerveless. 



Leaves flat ; pistillate spikes subglobose or short-cylindric, 



5-8 mm. thick ......... 179. C. saxatilis. 



Leaves involute or filiform ; pistillate spikes slender, 3-7 mm. 



thick .......... (179) C. saxaWis, v. miliaris. 



&.. Achenes trigonous; stigmas 3 (very rarely and exceptionally 2) K. 



K. SPIKES SOLITARY, TERMINAL L. 



L. Spikes naked or without large leafy bracts M. 

 M. Leaves tongue-shaped, 2-4 cm. broad ..... 77. (7. Fraseri. 



M. Leaves grass-like, narrow N. 

 N. Spikes monoecious, green or straw-color ; perigynia gla- 



brous O. 

 O. Spikes staminate at tip, few-flowered ; perigynia with entire 



tips. 

 Perigynia appressed-ascending, in a linear-cylindric 



spike, beakless. 



Perigynia 2.5-3.5 mm. long; achenes lustrous, not 

 puncticulate, obtusely trigonous .... 



Perigynia 4-5 mm. long ; achenes puncticulate, barely 

 lustrous, sharply trigonous ..... 



Perigynia soon refracted, slender-beaked 

 O. Spikes staminate at base, many-flowered ; perigynia with 



long bidentate beaks. 

 Scales of pistillate flowers subulate-tipped 

 Scales blunt ......... 



N. Spikes dioecious, purplish-brown ; perigynia pubescent. 



Culms shorter than the leaves ; scales short-aristate, ex- 

 ceeding the perigynia ....... 



Culms exceeding the leaves ; scales blunt, shorter than 



the perigynia ......... 92. C. scirpoidea. 



L. Spikes subtended by long leafy bracts. 

 Perigynia somewhat 2-edged. 

 Scales all bracteate, overtopping the perigynia . 

 Only the lowest scales overtopping the perigynia 

 Perigynia globose, with slender cylindric beak 

 K. SPIKES 2 OR MORE P. 

 P. Perigynia not rigidly bidentate, the orifice entire or emar- 



ginale, the teeth if present soft and thin Q. 

 Q. Terminal spike bearing some pistillate flowers R. 

 R. Terminal spike pistillate throughout, brown or purplish, the 



lower spike much smaller ; perigynia hairy . 

 R. Terminal spike with both staminate and pistillate flowers S. 

 S. Terminal spike pistillate only at base ; the capillary pedun- 



cles often basal ; perigynia sharply angled . 

 S. Terminal spike pistillate at summit, or, if pistillate at base, 



the spikes mostly near the tip of the culm T. 

 T. Perigynia ascending U. 



U* Scales brown to purplish-black ; spikes globose, ovoid 

 or thick-cylindric V. 



75. C. leptalea. 



76. C. ffarperi. 

 74. C. pauciflora. 



161. C. squarrosa. 



162. C. typhinoides. 



. 116. C.picta. 



89. C. Backii. 



90. C. Willdenowii. 



91. C. Jamesii. 



92- C. scirpoidea. 



118. C. pedunculate. 



