SEDGE FAMILY 209 



26. Auomalae. 

 Represented b7 one species in our range 90. C. amplifolia. 



27. Atratae. 



Terminal spike staminate or sometimes with perigynia in the middle. 

 Basal sheaths not, filamentose. 



Culms few-leaved, strongly aphyllopodic 91. C. spectabilis. 



Culms many-leaved, clothed at base with dried-up leaves of previous year 



92. C. raynoldsii. 

 Basal sheaths filamentose _. 93. C. bifida. 



Terminal spike gynaecandrous ; i.e., the terminal flowers pistillate. 



Culms aphyllopodie, strongly purplish-red at base, the lower sheaths filamentose 



94. C. buxbaumii. 

 Culms phyllopodic. 



Spikes 3 to 5, not oblong-cylindric; perigynia walls not papery; perigynia 2.5 to 4.5 mm. 



long, nerveless or obscurely nerved on face, dull green to brownish-black. 

 Perigynia not papillate-roughened. 



Spikes contiguous, sessile or nearly so, forming a dense head; scales lanceolate, 



strongly exceeding perigynia; culms stiff, erect 95. C. helleri. 



Lower spike or spikes more or less peduncled, usually distant, erect or nodding ; 



scales wider, shorter than or about equaling perigynia ; culms more slender. 



Scales with midvein largely obsolete; mature perigynia 3.5 to 4.5 mm. long, as 



wide or wider on either side than achene, the latter on stipe of nearly its 



own length ; sheaths not purplish-tinged ventrally 96. C. epapttlosa. 



Scales with prominent midvein; mature perigynia 3.5 mm. long, narrower on 

 either side than achene, the latter much longer than its stipe; sheaths 



normally purplish-tinged ventrally 97. C. heteroneura. 



Perigynia papillate-roughened, especially on upper margins 98. C. albo-nigra. 



Spikes 6 to 10, oblong-eylindric ; perigynia 5 mm. long, lightly 3-nerved, light green, the 

 walls papery; scales much shorter than perigynia 99. C, mertensii. 



28. Acutae. 



A. FLOWERING CULMS ARISING FROM THE CENTER OF PREVIOUS YEAR'S TUFT OF LEAVES AND 



SURROUNDED AT BASE WITH DRIED-UP LEAVES OF PREVIOUS YEAR. 



1. Lower sheatlis of flowering culms not breaking and becoming filamentose. 



Strongly stoloniferous, the culms arising one to few together, low; lowest bract normally much 



shorter than inflorescence; scales with obsolete or slender midvein. 



Dried first year leaf-blades at base of fertile culms stiff, rigid and conspicuous, concealing 

 the culms; fertile culm leaves all blade-bearing, the lower sheaths not purplish or his- 



pidulous dorsally 100. C. scopulorum. 



Dried first year leaf-blades at base of fertile culms much desiccated, not stiff, rigid or con- 

 spicuous, and not concealing the culms; lowest fertile culm leaves not blade-bearing, 

 the lower sheaths purplish and more or less strongly hispidulous dorsally 



101. C. gymnodada. 

 Culms taller, less stiff, in larger clumps; lowest bract equaling or exceeding inflorescence; scales 



with slender midvein or broader light colored center. 

 Perigynia strongly nerved ventrally, the nerves raised. 



Perigynia coriaceous, sessile or nearly so, the beak bidentate; strongly stoloniferous 



102. C. nebraslcensis. 

 Perigynia membranaceous, more or less slenderly stipitate, the beak entire; cespitose. 



Perigynia substipitate, orbicular, minutely papillate-roughened; scales deciduous 



103. C. paucicostata. 

 Peryginia strongly stipitate, ovate. 



Perigynia yellowish-green, ribbed, papillate-roughened; scales deciduous 



104. C. hindsii. 

 Perigynia light green or in age glaucous green, nerved, very minutely granular; 



scales long persistent 105. C. Tcclloggii. 



Perigynia nerveless ventrally or with obscure impressed nerves. 



Sheaths colored ventrally at mouth ; lower pistillate spikes cernuous or subcernuous on 



long peduncles; scales in age whitened at tip - 106. C. sitchcnsis. 



Sheaths not colored ventrally at mouth; lower pistillate spikes not nodding; scales not 



whitened at tip " 107. C. aquatilis. 



2. Lower or middle sheaths of flowering culms breaking and becoming filamentose. 



Beak of perigvnium bidentate. hispidulous between teeth; scales strongly rough-awned 



108. C. barbarae. 



Beak of perigynium entire or emarginate, not hispidulous between teeth; scales not rough- 

 awned. 



