WOOTOK AND STANDLEY FLOKA OF NEW MEXICO. 



683 



Leaves short, narrowly oblong, obtuse; heads 



numerous 6. A. boltoniae. 



Plants nowhere glandular. 



Outer bracts foliaceous, equaling or surpassing the inner. 



Plants low, 10 to 20 cm. high; leaves broad 8. A. apricus. 



Plants tall, 40 to 60 cm. ; leaves narrow 9. A. canbyi. 



Outer bracts not conspicuously foliaceous, shorter than 

 the inner. 

 Bracts pubescent on the back, usually cilia te. 



Bracts not bristle-pointed ; rays purple 10. A. vaUicola. 



Bracts bristle-pointed ; rays usually white. 



Pubescence of the stems spreading or re- 

 flexed . 

 Heads small, 5 mm. high or less, very 



numerous 11. A. hebedadus. 



Heads larger, 7 mm. long or more, few.. 12. ^-1. crassuhis. 

 Pubescence of the stems appressed. 



Heads small, about 5 mm. high, numer- 

 ous'; bracts much imbricated, often 



reflexed 13. A. muUiJIorus. 



Heads larger, 7 mm. high or more, few; 



bracts nearly equal, erect 14. ^4. commutatus. 



Bracts glabrous, sometimes ciliate. 



Leaves conspicuously ciliate 15. A. blepharophyllus. 



Leaves not ciliate. 



Plants glabrous throughout. 



Rays 2 mm. wide and 8 mm. long, showy; 



cauline leaves clasping 16. A. laevis. 



Rays 1 mm. wide or less, not more than 

 3 mm. long; cauline leaves not 

 clasping. 

 Stems much branched; leaves thick 

 and fleshy, short; heads long- 

 pedunculate 7. A. neomexicanus. 



Stems branched only above; leaves 

 thin, long; heads short-pedun- 

 culate 17 . A. exilis. 



Stems pubescent, at least with pubescent 

 lines above. 



Pubescence covering the peduncles 18. A. lonchophyllus. 



Pubescence in lin^s on the peduncles. 

 • Heads short-pedunculate or nearly 



sessile; leaves thick. 19. A. salidfolius. 



Heads long-pedunculate; leaves thin. 



Heads large, 10 to 15 mm. wide, 



few; stems little branched ; 



leaves of the inflorescence 



little reduced 20. A. wootonii. 



Heads smaller, usually less than 

 10 mm. wide, very nu- 

 merous; stems tall, much 

 branched; leaves of the 

 inflorescence much re- 

 reduced 21. A. hesperius. 



