COMPOSITAE 



195 



Lower leaves cordate, petioled. 



Leaves entire. 1. A. azureus, 



Leaves serrate. 



Heads 2 // -3 // high. 2. A. cordifolim. 



Heads 3"-5" high. 



Stems densely finely canescent. 3. A. Drummondii. 



Stems glabrous or nearly so. 4. A. sagittifolius. 



Stem leaves cordate-clasping. 

 Stems rough -hairy. 



Plants 3-8 high. 5. A. Novae- Angliae. 



Plants 2 or less high. 6. A. oUongifolius. 



Stems glabrous. 



Leaves oblong lanceolate to ovate. 7. A. laevis. 



Leaves linear-lanceolate. 8. A. concinnus. 



Stem leaves not cordate or cordate clasping. 



Leaves silvery on both sides. 9. A. sericeus. 



Leaves not silvery. 

 Stem leaves linear. 



Stems rough-pubescent. 10. A. exiguus. 



Stems glabrous to villous. 



Heads 3 X/ -4 X/ broad. 11. A. parviceps. 



Heads 4 // -6 // broad. 12. A . ericoides pilosus. 



Stem leaves lanceolate. 



Heads not one-sided on the branches. 

 Stems glabrous or nearly so. 



Kays violet. 13. A. mlicifolius. 



Rays white. 



Rays 3"-4" long. 14. A. paniculatus. 



Rays 2"-3" long. 15. A. Tradescanti. 



Stems finely canescent. 16. A. Missouriensis. 



Heads strongly one sided on the branches. 17. A. lateriflorus. 



1. A. azureus Lindl. l-3 high, rough or smooth : lower leaves ovate- 

 cordate to lanceolate, rough, the upper linear to lanceolate : involucral 

 scales strongly green-tipped : rays 10-26, bright blue. Not uncommon in 

 dry places throughout the southern part. September-October. 



2. A. cordifolius L. l-4high: lower leaves ovate- cordate, the upper 

 ovate to lanceolate : heads 2 // -3 // high : bracts obtusish to acute : rays 

 10-20, bluish. This and the next two species freely intergrade with us. 

 Abundant in woods. September-October. 



3. A. Drummondii Lindl. Distinguished from the last chiefly by 

 being finely and densely canescent all over and having heads 3 // -5 // high : 

 bracts more acute. Frequent in dry woods, especially in the southern 

 part. September-October. 



4. A. sagittifolius Willd. Like A. Drummondii, but whole plant 

 nearly glabrous and involucral scales looser. Dry oak woods near Dod- 

 son. September-October. 



5. A. Novae-Angliae L. Stems hairy : leaves lanceolate, entire, 

 pubescent : involucral scales spreading, glandular-viscid : rays 40-50, 

 violet-purple, 6" long. In moist grounds throughout, but uncommon. 

 August-October. 



6. A. oblongifolius Nutt. Stems glandular-puberulent : leaves ob- 



