CYPERACEAE (SEDGE FAMILY) 



205 



7. C. pratensis. 



8. O. tribuloides. 

 C. tribuloides, v. turbata. 

 C. tribuloides, v. reducta. 



J, Perigynia firm, obviously distended over the achenes, 

 nerveless or obscurely nerved on the inner face, equaled 



by the subtending scales 



G. Perigynia less than 5 rnra. long K. 

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



leaves 3-8 mm. broad. 

 Perigynia with appressed tips. 

 Inflorescence cylindric ; spikes approximate 

 Inflorescence moniliform ; spikes scattered . . . (3) 

 Perigynia with spreading tips ; inflorescence flexuous (3) 

 K. Perigynia firm, 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 drn. high ; leaves 1-2.5 mm. wide ; spikes 



3-7 mm. long 5. C. Crawfordii. 



Culms taller ; leaves broader; spikes 8-11 mm. long (5) C. Crawfordii, 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 perigynia with 



recurved or spreading tips concealing the scales 

 0. Spikes with ascending or slightly spreading perigynia ; 



scales apparent P. 



P. Mature perigynia 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-cylindric heads. 



Scales pale, not strongly contrasting with the 



perigynia 



Scales dark chestnut, strongly contrasting with 



the perigynia (10) C. mirabilis, v. tincta. 



Spikes scattered in a moniliform inflorescence (10) C. mirabilis, v. perlonga. 

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



most 2.2 cm. long ; scales pale brown . . 18. C. Bebbii. 

 N. Leaves narrower. 



Inflorescence stiff, with crowded closely flowered spikes 18. C. Bebbii. 

 Inflorescence flexuous and moniliform, or at least with 

 the loosely flowered spikes scattered 



8. C.cristata. 



10. C. mirabilis. 



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

 Q. Inflorescence stiff and 



11. C. straminea. 



20. C. leporina. 



21. C. xerantica. 



7. C. pratensis. 

 22. C. aenea. 



erect, or at least with spikes 

 approximate. 



Spikes brown or ferruginous 



Spikes brownish-white 



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



remote. 

 Perigynia nerveless or minutely short-nerved on the 



inner face. 

 Mature perigynia straw-colored or pale brown, one 



third as broad as long 



Mature perigynia olive-green or bronze, half as broad 



as long 



Perigynia with strong ribs the length of the inner face ; 



spikes silvery-green 19. O. foenea. 



F. Perigynia 2 mm. or more broad R. 



R. Tips 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. 



Perigynia 7-10 mm. long 1. C. muskingumensis. 



Perigynia shorter 2. C. sooparia. 



8. 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 



U. Leaves narrower. 



Perigynia distinctly about 10-nerved on the inner faces, 



4-6 mm. long. 



Spikes 8-12 mm. long; perigynia 4.8 6 mm. long 

 Spikes 5-8 mm. long ; perigynia 4-5 mm. long (12) C. hormathodes, v. invisa. 

 Perigynia 8-5-nerved on the inner faces, mostly less than 



4 mm long. 



Perigynia with ascending inconspicuous tips . . 11. C. straminea. 

 Perigynia with divergent conspicuous tips . (11) C. straminea, v. echinodet, 

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

 V. Inflorescence moniliform and flexuous, with mostly clavate- 

 based spikes. 



10. C.mirabiUs. 



12. C. hormathodes. 



