THE GENUS CAREX IN CALIFORNIA 15 



23. Triquetrse. 



Lowest bract sheathless or very short-sheathing; spikes approximate; perigynia glabrous, strongly 



ribbed or nerved 77. C. Whitneyi. 



Lowest bract long-sheathing; lower spikes more or less strongly separate; perigynia hairy, faintly 

 nerved or nerveless. 

 Leaf-blades hairy: spikes oblong or short-oblong, the upper approximate. 



Perigynia 4-5 mm. long, round-tapering at base, finely many-nerved 78. C. gynodynama. 



Perigynia 3.5-4 mm. long, tapering at base, 2-keeled, obscurely striate 79. C. hirtissima. 



Leaf-blades not hairy; pistillate spikes linear, widely separate 80. C. triquetra. 



24. Debiles. 



Represented by one species in our range 81. C. mendocinensis. 



25. Frigidse. 



Perigynia triangular or slightly flattened, the beak bidentulate; scales obtusish, the midvein not 

 prominent at apex. 

 Spikes widely separate, the staminate one strongly overtopping the uppermost pistillate one; 



perigynia triangular, 3.5 mm. long or less; lower bracts with conspicuous blades 



82. C. Lemmonii. 



Uppermost pistillate spikes bunched, little exceeded by the staminate one; perigynia compressed- 

 triangular, longer; bracts with rudimentp.ry blades. 



Pistillate spikes oblong; scales reddish-brown 83. C. luzulina. 



Pistillate spikes linear-oblong; scales dark-tinged 84. C. ablata. 



Perigynia strongly flattened, the beak bidentate; scales sharp-pointed with midvein prominent to apex. 

 Perigynia glabrous; scales smooth; bract sheaths strongly enlarged upward; leaf-blades very 



leathery 85. C. luzulcefolia. 



Perigynia sparsely hairy; scales more or less hairy; bract sheaths scarcely enlarged upward; leaf- 

 blades not leathery 86. C. fissuricola. 



26. Anomalse. 



Represented by one species in our range 87. C. amplifolia. 



27. Atratae. 



Terminal spike staminate or sometimes with perigynia in the middle. 

 Basal sheaths not filamentose. 



Culms few-leaved, strongly aphyllopodic 88. C. spectabilis. 



Culms many-leaved, clothed at base with dried-up leaves of previous year. ...89. C. Raynoldsii. 

 Basal sheaths filamentose 90. C. bifida. 



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



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



91. C. Buxbaumii. 



Culms phyllopodic. 



Spikes 3-5, not oblong-cylindric; perigynia walls not papery; perigynia 2.5-4.5 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 92. 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 3.5-4.5 mm. long, 



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



own length; sheaths not purplish-tinged ventrally 



93. C. epapillosa. 



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 94. C. heteroneura _ 



Perigynia papillate-roughened, especially on upper margins 95. C. albo-nigra. 



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

 walls papery; scales much shorter than perigynia 96. C. Mertensii. 



