104 Karl M. Wiegand and Arthur J. Eames 



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h. Perigynia 4.2-6 mm. long ; scales more or less fuscous ; leaves 



2-3 mm. wide 5. C. contigua 115 



h. Perigynia 3.8 mm. long or less ; scales green, stramineous, 

 tawny, or whitish. 

 i. Leaves 1—4.5 mm. wide ; sheaths close. 



j. Perigynia spongy-thickened at base, and in that region 

 puckered when dry ; inflorescence more or less interrupted, 

 or spikes scattered. 

 k. Beak smooth, scarcely exceeding the tawny, acute scale. 



6. C. retroflexa 115 

 k. Beak scabrous, much exceeding the silvery white, rarely 

 tawny, obtuse or subacute scale. 

 /. Broadest leaves (1.8) 2-3 mm. wide; sheaths at base of 

 culm 1.5-2 mm. in diam. ; perigynia broadly elliptic- 

 ovoid, 3-4.2 mm. long (perigynia deep green, in the 

 lower spikes 9-12 rarely 6-20 in number, the wall 

 thin, the beak prominent, thin, plainly bidentate, 

 strongly serrulate ; stigmas stout, short, curved ; scales 

 pale, obtuse; fruit May 25-June 20).. 7. C. convoluta 115 

 '. Broadest leaves 0.8-1.8 (2) mm. wide; sheaths at base 

 of culm 0.7-1.2 mm. in diam.; perigynia 2.2-3.2 mm. 

 long. 

 vi. Perigynia 2.8-3.2 mm. long, elliptic-oblong or ob- 

 long-ovoid, olive green, spreading, firm-walled, in 

 the lowest spikes 5-8 (3-12) in number; apex 

 abruptly acute, firm, obscurely bidentate, minutely 

 serrulate ; base as broad as the body, conspicuously 

 spongy ; stigmas long, slender, usually reflexed but 

 not coiled; scales obtuse, often tawny; lowest 

 bract short, 5-30(60) mm. long; broadest leaves 

 about 1.3—1.8 (2) mm. wide, light green; fruit 



May 25-June 25 8. C. rosea 116 



;;/. Perigynia 2.2-2.8 (3) mm. long, elliptic-ovoid, deep 

 green, usually ascending, thin-walled, in the lowest 

 spikes 2-6 in number ; apex more beak-like, less 

 firm, plainly bidentate, strongly serrulate ; base 

 more obscurely spongy ; stigmas short, less slender, 

 usually coiled ; scales obtuse, acute, or subaristate, 

 whitish, rarely slightly tawny ; lowest bract more 

 conspicuous, 30-50 mm. long or a few on each plant 

 shorter; broadest leaves 0.8-1.2 mm. wide, deep 

 green; fruit June (10) 20-July 30... 9. C. radiata 116 

 /. Perigynia not spongy at base and not puckered in drying, 

 elliptic-ovoid (2.8-3.2 mm. long). 

 k. Inflorescence (1.5) 2-4 cm. long, usually interrupted; 

 leaves stiff and wiry ; perigynia ovoid-oval, very short- 

 beaked, firm-walled ; clumps smaller and more open 

 than in the next species ; rootstocks stout, somewhat 



creeping 10. C. Muhlenbergii, var. enervis 116 



k. Inflorescence 0.8-1.5 cm. long, dense; leaves softer; 

 perigynia rhombic-ovoid, longer-beaked, thin-walled ; 

 plant cespitose 11. C. cephalophora 116 



