CYPERACEAE (^SEDGE FAMILY) 



205 



J. Peri^A-nia firm, obviously distended over the achenes, 

 nerveless or obscurely nerved on the inner face, equaled 



by the subtending scales 7. C praienHs. 



G. Perig-ynia less than 5 mm. long K. 

 K. Perigynia thin, scale-like, scarcely distended over the achenes ; 

 leaves 3-S mm. broad. 

 Perigynia with appressed tips. 



Indorescence cj-hndric ; spikes approximate ... 3. C. ti'ihuloideK. 



/ Inflorescence raoniHform ; spikes scattered . . . 03) C. tribuloides, v. tmhata. 

 Perigynia with spreading tips; inflorescence flexuous (3) C. tribuloidefs, \. reducta. 

 K. Perigynia flrra, obviously distended over the achenes L. 



L. Perigynia elongate-lanceolate or subulate, less than one third 

 as broad as long, at most 1.4 mm. broad. 

 Tips of the perigynia conspicuously exceeding the lance- 

 subulate dull scales. 

 Culms 1-4 dm. high ; leaves 1-2.5 mm. %vide ; spikes 



3-7 mm. long 5. T. Ch'awfordii. 



Culms taller ; leaves broader ; spikes S— 11 mm. long (5) C. Ci (iicfordii, v. vigens. 

 Tips of the perigynia equaled by the ovate bluntish glossy 



dark scales " . . . ' 6. C. oronensis. 



L. Perigynia broader, nearly or quite half as broad as long M. 

 M. Tips of perigynia distinctly exceeding the subtending scales N. 

 N. Leaves 2.5 mm. or more wide 0. 



O. Spikes compactly flowered, the mature perigj'nia with 



recurved or spreading tips concealing the scales . 8. C. cristata. 

 O. Spikes with ascending or slightly spreading perigynia ; 

 scales apparent P. 

 P. Mature perigvnia greenish or pale straw-colored, in 

 loose spikes ; inflorescence more than 2.2 cm. long 

 (if shorter, with dark chestnut scales). 

 Spikes approximate in ovoid or short-cvlindric heads. 

 Scales pale, not strongly contrasting with the 



perigynia 10. C. rnirdbilifs. 



Scales dark chestnut, strongly contrasting with 



the perigynia (HO C. mirahUiH, v. tincta. 



Spikes scattered in a moniliform inflorescence (10) C. mirabilis, \ . jjerJonga, 

 P. Mature perigynia brown, in dense spikes ; heads at 



most 2.2 cm. long ; scales pale brown . . 13. C Bebhii. 

 N. Leaves narrower. 



Inflorescence stifl", with crowded closely flowered spikes 18. C. Bebbii. 

 Inflorescence flexuous and moniliform, or at least with 



the loosely flowered spikes scattered . . .11. C. straminea. 

 M, Tips of perigynia equaled by the subtending scales Q. 



Q. Inflorescence stiff and erect, or at least ^-ith spikes 

 approximate. 

 Spikes brown or ferruginous . . . . . . 20. T. leporiva. 



Spikes brownish-white 21. (7. xerantica. 



Q. Inflorescence flexuous, or at least with the lower spikes 

 remote. 

 Perigvnia nerveless or minutely short-nerved on the 

 inner face. 

 Mature perigynia straw-colored or pale brown, one 



third as broad as long 1. C. iwaUnnU. 



Mature perigynia ohve-green or bronze, half as broad 



as long " 22. C. aenea. 



Perigynia with strong ribs the length of the inner face ; 



spikes silvery-green 19. (7. foenea. 



F. Perigynia 2 mm. or more broad E. 

 R. Ti|is of the perigynia distinctly exceeding the subtending scales S. 

 S. Perigynia thin and scale-like, barely distended over the achenes, 

 one fourth to one third as broad as long. 



Perigvnia 7-10 mm. long \. C. mnskingumenniti, 



Perigynia shorter 2. C scoparia. 



S. Perigynia firmer, obviously distended over the achenes, nearly 

 or quite half as broad "as long T. 

 T. Perigynia lance-ovate, about half as broad as long U. 



U. Leaves 2.5 mm. or more broad 10. C.mirnbiliH, 



U. Leaves narrower. 



Perigvnia di-^tinctly about 10-nerved on the inner faces, 

 4^6 mm. long. 

 Spikes S-12 mm. long: perigynia 4.8 6 mm. long . 12. C hornutthod^s. 

 Spikes 5-S mm. long; perigj^nia 4-5 mm. long (12) ('. hormathodeK. v. incisa. 

 Perigynia 3-5-nerved on the inner faces, mostly less than 

 4 mm lung. 

 Perigynia with ascending inconspicuous tips . . 11. (^. utra mined. 

 Perigynia with divergent conspicuous tips . (11) C. ntnimittea. y. ec'iinodea, 

 T. Perigynia witli broad-ovate to orbicular bodies V. 

 V. Inflorescence inoniHform and flexuous, with mostly clavate- 

 based spikes. 



