84 
Cyperaceae re 
AA. Perigynia smooth but the margins above serrulate. U. 
C. laciniata Boott 
AAA. Perigynia smooth thruout. 
D.  Perigynia longer than the scales. 
E.  Pistillate scales rough-awned. C-. 
C. gmelini Hook. 
EE.  Pistillate scales awnless or merely mucronate. 
F. Bracts about equaling the stem; pistillate scales brown. E 
braskensis ultriformis. ) 
C. nebraskensis Dew- 
FF. Bracts short; pistillate scales purple-black. C. 
C. spectabilis Bail. 
DD.  Perigynia 1/3—!4 as long as the scales. 
* G. Pistillate spikes sessile or nearly so, erect. C. E. 
Gi aperta Boott 
GG. Pistillate spikes long-stalked, drooping. 
H. Leaves pale-green, withering at the first frost; staminate spike stalked; 
perigynia light-colored. W. 
C. eryptocarpa Mey. 
HH. Leaves very dark-green, persistent thruout the winter; staminate spike 
sessile; perigynia purple-brown. W. C.  (C._ sitchensis Hook.) 
C. magnifica Dew. 
GROUP 8 
A. Pistillate spikes rounded to oval. 
B.  Pistillate spikes 5—-12 mm. long. C. E. 
C. alpina Sw. 
BB.  Pistillate spikes |2—40 mm. long. C. E. 
C. atrata L. 
AA.  Pistillate spikes oblong to long-cylindric. 
C.  Perigynia much longer than the scales. W. C. E. 
C. mertensii Pers. 
CC. Perigynia equaling or shorter than the scales. 
D. Scales purple, without white center. W. C. E. 
C. scofpulorum Holm 
DD. Scales brown, sometimes purplish but then with white center. 
E. Scales with white center; perigynia smooth. 
F. Scales acute or rough-awned. U. 
C. laciniata Boott 
FF. Scales obtuse or rounded. U. C. 
C. barbarae Dew. 
EE. Scales without white center; perigynia granulate, often rough-angled. 
W.C. (C. howellii.) - 
C. dives Bail. 
GROUP 9 
A. Pistillate scales brown or green. 
B. Lower leaf-sheaths prominently fibrillose. W. E. 
C. stricta Lam. \ 
BB.  Leaf-sheaths not fibrillose. 
(C. ne- 
(C. invisa.) 
(C. chalciolepis; C. atrata nigra.) 
(C. tolmiei and varieties. ) 
C. Spikes densely-flowered thruout, the lower short-stalked; perigynium-beak 2- 
toothed. E. (C. nebraskensis ultriformis.) 
‘C. nebraskensis Dew. 

