106 Karl M. Wiegand and Arthur J. Eames 



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d. Perigynia without winged margins, with definite thick margins, or mar- 

 ginless. (Elongatae.) (2d d, p. 107.) 

 e. Perigynia 4-5 mm. long, elliptic-lanceolate, contracted at base, spongy 

 where in contact with the achene, slender-beaked, ascending; spikes 

 5-20 mm. long. 

 /. Spikes ovoid-oblong, silvery green; perigynia 1.5-1.9 mm. wide, 

 faintly nerved; scales ovate; leaves 2-5 mm. wide. 



22. C. Deweyana 118 

 /. Spikes linear, tawny; perigynia 1-1.3 mm. wide, strongly nerved; 



scales oblong ; leaves 1-2.5 mm. wide 23. C. bromoides 118 



e. Perigynia 2-4 mm. long, elliptic or ovoid or lanceolate, contracted or 

 rounded at base, not spongy where in contact with the achene, short- 

 or rather slender-beaked, ascending or spreading ; spikes 9 mm. long 

 or less. 

 /. Perigynia elliptic, slightly contracted at base, greenish glaucous, 

 ascending-appressed ; plant pale. 

 g. Perigynia 2.5-3.5 mm. long, finely many-nerved, turgid; spikes 

 2-5-flowered ; inflorescence very open, often zigzag ; plant laxly 

 cespitose or stoloniferous. 

 /;. Perigynia subterete, 2.5-2.8 mm. long, blunt; inflorescence 

 straight; bracts short; spikes staminate at apex (exceptional 



in this group) 24. C. tenella 118 



h. Perigynia plano-convex, 3-3.5 mm. long, apiculate ; inflorescence 

 zigzag, usually exceeded by the lower bract; spikes staminate 



at base 25. C. trisperma 118 



g. Perigynia about 2 mm. long, few-nerved, less turgid, plano-convex ; 

 spikes 7-many-flowered ; inflorescence contracted or open, not 

 zigzag ; plant cespitose. 

 h. Leaves 2-4 mm. wide, glaucous; spikes many-flowered; 

 perigynia apiculate. 



i. Inflorescence 2-5 cm. long 26. C. canescens 119 



i. Inflorescence 5-15 cm. long, the lower spikes remote. 



26a. C. c, var. disjunct a 119 

 h. Leaves 1-2.5 mm. wide, green ; spikes 7-10-flowered ; perigynia 



distinctly short-beaked, more spreading 27. C. brunnescens 119 



/. Perigynia ovoid, broadest below the middle, rounded or subcordate 

 at base, pale yellowish or brown ; plant pale or green. 

 g. Leaves flaccid, pale green ; perigynia ascending, short-beaked, 

 rounded at base, pale green, the margins not prominent ; spikes 



aggregated [C. arcta] 119 



g. Leaves somewhat more rigid, green, rarely paler ; perigynia 



spreading, more definitely and acuminately beaked, rounded or 



truncate or subcordate at base, yellowish green, less cellular, the 



margins prominent; spikes aggregated or scattered. 



/;. Scales, at least the lower ones, nearly or quite equaling the 



perigynia, the lower scales obtuse, the upper ones acutish, all 



the scales more or less colored, firm; perigynia firm and 



moderately thick, triangular-ovoid, the nerves not prominent, 



those of the inner face more or less evident ; beak of medium 



size, sharply serrulate and sharply notched; spikes (3) 4-6 



(7), subcontiguous ; broadest leaves 1.5-2 (2.5) mm. wide; 



sheaths truncate at orifice; anthers 1.2-2 mm. long. 



28. C. sterilis 119 

 h. Scales distinctly shorter than the perigynia (or, if nearly 

 equaling them, the sheath more or less V-shaped at summit and 

 the perigynia narrower or the spikes more distant). 



