WOOTON AND STANDLEY FLORA OF NEW MEXICO. 119 



Pistillate spikes erect or, if drooping, the perigynia 

 differing from above. 

 Achenes normally lenticular and the stigmas 2. 

 Perigynia golden yellow at maturity; spikes 

 few-flowered; plants low, slender. (Bi- 



colores.) 28. C. aurea. 



Perigynia not golden yellow at maturity; 

 spikes many-flowered; plants tall or 

 stout. (Rigidae.) 

 Perigynium beak strongly bidentate; peri- 

 gynia ribbed 33. C. nebrasken- 



sis. 

 Perigynium beak, if present, not bidentate; 

 perigynia various. 

 Lowest bract not exceeding the inflores- 

 cence 29. ft scopulorum 



Lowest bract exceeding the inflores- 

 cence. 

 Perigynia pale green, finely many- 

 nerved 30. C. kelloggii. 



Perigynia greenish sjtraw-colored, few- 

 nerved or nerveless. 

 Leaf blades flat and canaliculate, the 

 edges serrulate above only; peri- 

 gynia at most obscurely nerved. .31. C. variabilis. 

 Leaf blades, at least the lower, pli- 

 cate, the margins revolute, the 

 edges serrulate throughout; peri- 

 gynia few-nerved 32. ('. emoryi. 



Achenes triangular; stigmas 3. 



Perigynia beakless or very shortly beaked. 

 Terminal 2 or 3 spikes staminate. (Tka- 



CHYCHLAENAE.) 37. ft ultra. 



Terminal spikes pistillate above, stami- 

 nate below. (Atijatae.) 

 Perigynia 2.5 mm. long or less, little 

 compressed, the margins not ap- 

 pearing winglike 34. ( '. halleri. 



Perigynia more than 2.5 mm. long, 

 strongly compressed, the margins 

 winglike. 

 Spikes all closely sessile, contiguous, 



forming a dense lobed head :'.">. ft nova. 



Lateral spikes ped uncled, distant, 



usually nodding 36. ft 



Perigynia Btrongly beaked, the beak deeply 

 bidentate 

 Perigynia or sheaths pubescent. (Hib- 



TA B . ) 



Perigynia pubescent, the teeth Bhorl ; 



sheaths glabrous 38. ft lanuginosa. 



Perigynia glabrous, the teeth lm 



Bheaths pube cenl 89 ft atkerod 



