WOOTON AND STANDLEY—FLORA OF NEW MEXICO, 117 
KEY TO THE SPECIES. 
Achenes lenticular; stigmas 2; terminal spike partly pistillate or 
if staminate the lateral spikes short or heads dicecious. 
(VIGNEA.) 
Spikes mostly staminate at the base. 
Perigynia not wing-margined. (STELLULATAE.) 
Perigynia with very short beaks, widely spreading at 
maturity........22---2 2-2 eee ee eee eee eee 13. C. interior. 
Perigynia with long beaks, appressed............-.-- 14. C. bolandert. 
Perigynia wing-margined. (OVALES.) 
Beak of the perigynium flattened and margined to the 
tip. 
Scales strongly tinged with reddish brown........21. C. wootont. 
Scales little if at all tinged with reddish brown. 
Perigynia thin, lanceolate (at least two and 
one-half times as long as wide).......- 19. C. scoparia. | 
Perigynia thick, ovate........-....-.-.-..-- 20. C. festucacea. 
Beak of the perigynium slender, nearly terete and 
scarcely margined at the apex. 
Several of the bracts conspicuously exceeding the 
head......--. 22 eee eee eee eee eee eee 18. C. tenuirostris. 
Bracts inconspicuous. 
Perigynia 2.5 to 3.5 mm. long; culms smooth 
beneath the head...........--..-.----- 15. C. subfusca. 
Perigynia 4.5 to 6 mm. long; culms rough be- 
neath the head. 
Perigynia about 4.5 mm. long, ovate.....16. C. festiva. 
Perigynia 4.5 to 6 mm. long, lanceolate. .17. C. ebenea. 
Spikes staminate at apex or some spikes wholly staminate. 
Perigynia little compressed, whitish-puncticulate. 
(TENELLAE.).....--- +2202 eee ence eee eee eee eee 12. C. disperma. 
Perigynia strongly compressed, not whitish-puncticulate. 
Culms one to few together, the rootstocks long and 
creeping. 
Perigynia wing-margined, the beak bidentate. 
(ARENARIAE,)....2..020-.000 2020s eee eee eee 5. C. siccata. 
Perigynia not wing-margined, the beak obliquely 
cut, or bidentate in age. (DIVISAE.) 
Culms smooth above; rootstocks slender. ...-. 1. C. douglasit. 
Culms rough beneath the head; rootstocks 
stout. 
Perigynia chestnut, scarcely sharp-edged, 
the beak about one-fifth the length 
of the body at maturity.......... 4. C. simulata. 
Perigynia brownish or blackish, sharp- 
edged, tapering into a beak about 
half the length of the body. 
Spikes with one to several perigynia, 
the heads appearing a mass of 
straw-colored scales; staminate 
flowers conspicuous; perigyn- 
ium body at maturity about 
2mm. wide.................-. 2. C. latebrosa. 
