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. nebrasJcen- 



■ sis. 

 Perigynium beak, if present, not bidentate; 

 perigynia various. 

 I^owest bract not exceeding the inflores- 

 cence 29. C scopulorum^ 



Lowest bract exceeding the inflores- 

 cence. 

 Perigynia pale green, finely many- 

 nerved 30. C. kelloggii. 



Perigynia greenish straw-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. C. emoryi. 



Achenes triangular; stigmas 3. 



Perigynia beakless or very shortly beaked. 

 Terminal 2 or 3 spikes staminate. (Tra- 



CHYCHLAENAE.) 37. C. ultra. 



Terminal spikes pistillate above, stami- 

 nate b elow . ( Atr ATA E . ) 

 Perigynia 2.5 mm. long or less, little 

 compressed, the margins not ap- 

 pearing w inglike 34 . C. halleri. 



Perigynia more than 2.5 mm. long, 

 strongly compressed, the margins 

 winglike. 

 Spikes all closely sessile, contiguous, 



forming a dense lobed head 35. C. nova. 



Lateral spikes peduncled, distant, 



usually nodding 36. C. hella. 



Perigynia strongly beaked, the beak deeply 

 bidentate ' 

 Perigynia or sheatlis pubescent. (Hir- 



TAE.) 



Perigynia pubescent, the teeth short; 



sheaths glabrous 38. C. lanuginosa. 



Perigynia glabrous, the teeth long; 



sheaths pubescent 39. C. atherodes. 



