22a. Bracts with straight tips; Page No. 



heads 11 to 15 mm long 



C. parryi 



ssp. attenuatus 52 



22b. Bracts with recurved tips; 

 heads 14 to 19 mm long 



C. parryi 



ssp. nevadensis 53 

 (Nevada rabbitbrush) 



17b. Bracts acute to obtuse; inflorescence mostly cymose 



C. nauseosus 



complex 43 

 (rubber rabbitbrush) 



23a. Leaves usually grayish-white; involucral bracts 

 puberulant or tomentose. 



24a. Leaves 3 to 10 mm wide, 4 to 8 cm long; 



bracts mostly obtuse C. nauseosus 



ssp. salioifolius 47 

 (mountain rubber rabbitbrush] 



24b. Leaves 3 mm or less wide, 2.5 to 4 cm long; 



bracts mostly acute C. nauseosus 



ssp. albioaulis 45 

 (white rubber rabbitbrush] 



23b. Leaves usually greenish-yellow; involucral bracts 

 glabrous . 



25a. Leaves 1 to 3 mm wide, 4 to 6 cm long; 



mildly ill-scented C. nauseosus 



ssp. graveolens 47 

 (green rubber rabbitbrush) 



25b. Leaves less than 1 mm wide 2.5 to 5 cm 



long; strongly disagreeable odor 



C. nauseosus 



ssp. aonsvnilis 46 

 (threadleaf rubber rabbitbrush] 



77 



