206 



CYPERACEAE (SEDGE FAMILY) 



Spikes brownish-white, of closely appressed ob- 

 scurely beaked firm perigynia . . . . 14. O. silicea. 

 Spikes ferruginous; the abrupt slender beaks of 

 the perigynia with loosely ascending or spread- 

 ing tips (12) C. hormathodes, v. Richii. 



V. Inflorescence stiff (or, if flexuous, with brown or 



ferruginous spikes) W. 

 W. Perigynia 5.6-7.7 mm. long, very thin, scale-like, 



almost transparent ; scales blunt . . .13. C. BickneUii. 

 W. Perigynia less than 5.6 mm. long, firm and opaque 

 (when exceptionally longer in C. alata, with 

 aristate scales) X. 

 X. Scales long-acuminate or aristate ; perigynia 



4-5.5 mm. long ; achenes oblong. 

 Spikes green or finally dull brown ; scales lance- 

 subulate ; perigynia obovate, 2.8-3.7 mm. 

 broad, abruptly narrowed at base . . 15. C. alata. 

 Spikes becoming dark brown or ferruginous ; 



perigynia 2.8-'2.S mm. broad. 

 Spikes closely approximate ; scales ovate- 

 lanceolate ; perigynia ovate, tapering 

 gradually to the beak . . . . 16. C. (suberecta. 

 Spikes scattered in a flexuous inflorescence ; 

 scales lanceolate ; perigynia orbicular, 



abruptly slender-beaked . . (12) C. hormathodes, v. Richii. 

 X. Scales blunt or at most acutish. 



Spikes gray-green or finally dull brown, with 

 strongly appressed-ascending very firm 



perigynia 3.5-4 (very rarely 4.5) mm. long 9. C. albolutescens. 

 Spikes straw-colored or ferruginous, with 



spreading-ascending perigynia 4-5.5 mm. long. 

 Inflorescence of 5-10 mostly distinct spikes . 17. C.festucacea. 

 Inflorescence of 3-6 approximate spikes (17) C. festucacea, v. brevior. 

 R. Tips of the perigynia equaled by the subtending scales Y. 

 Y. Inflorescence stiff and erect, or at least with approximate 



spikes Z. 

 Z. Spikes whitish or gray-green. 



Perigynia lance-ovate, 4-4.8 mm. long, nerveless on 



the inner face, golden-yellow at base . 

 Perigynia broad-ovate to suborbicular. 

 Perigynia strongly ribbed the length of the inner 



face, 2 mm. broad 



Perigynia nerveless or faintly nerved on the inner 



face, broader 



Z. Spikes bronze or ferruginous. 



Perigynia distinctly concave on the usually nerved 



inner face ; achene 1 mm. broad .... 



Perigynia flat or convex on the usually nerveless 



inner face, very plump ; achene 2 mm. broad 

 Y. Inflorescence flexuous, at least the lower spikes remote a. 

 a. Perigynia nerveless or only faintly short-nerved on the 



inner face. 

 Perigynia ovate-lanceolate, one third as broad as 



long; achene 1 mm. broad 



Perigynia ovate, half as broad as long ; achene 1.5mm. 



broad 



a. Perigynia distinctly nerved on the inner face. 



Perigynia 2.S-4.4 mm. long, at most 2.4 mm. broad, 



7-13-ribbed on the inner face, abruptly beaked. 

 Inflorescence of 4-9 spikes 6-10 mm. long ; peri- 

 gynia 2.8-4 mm. long 



Inflorescence of 615 spikes 10-17 mm. long; 



perigynia 3.5-4.4 mm. long . . . (15 



Perigynia 4-5.3 mm. long, 2.53 mm. broad, 3-;>- 



nerved on the inner face, obscurely broad-beaked 14* C. silicea. 

 D. Bracts leaf-like, much prolonged, the lowest 1-2 din. long; 



spikes crowded ; perigynia subulate 



C. Perigynia horizontally spreading or reflexed when mature, spongy 



at base, with thin but scarcely winged margins b. 

 b. Spikes solitary and terminal, pistillate or staminate, or with 



flowers variously scattered. 



Stoloniferous; the filiform culms at most 3 dm. high, from fili- 

 form rootstocks 



Not Stoloniferous ; the wiry culms 27 dm. high, in caespitose 



stools 



6. Spikes 2-several c. 



c. Perigynia broadest at base ; beak rough or serrulate d. 



21. O. ocerantica. 



19. C.foenea. 

 9. C. albolulescens. 



20. C. leporina. 

 23. 



7. C. pratensis. 

 22. O. aenea. 



19. C.foenea. 

 ) O. foenea, v. perplexa 



24. C. sychnocepJiala. 



25. C. gynocrates* 



26. O. 



d. Perigynia at most half as broad as long, finally yellowish, with 

 slender beak nearly equaling the body ; scales p 



scales pointed 



