COMPOSITAE 



195 



A. Drummondn. 

 A. sagitiifolius. 



Novae- Angliae. 

 ohlongifulius. 



Lower leaves cordate, petioled. 



Leaves entire. 1. A. azuretis. 



Leaves serrate. 



Heads 2^^-3^^ high. 2. A. cordifoUus. 



Heads S''-5'' high. 

 Stems densely finely canescent. 

 Stems glabrous or nearly so. 

 Stem leaves cordate-clasping. 

 Stems rough -hairy. 

 Plants 3°-8° high. 

 Plants 2° or less high. 

 Stems glabrous. 



Leaves oblong lanceolate to ovate. 

 Leaves linear-lanceolate. 

 Stem leaves not cordate or cordate clasping. 

 Leaves silvery on both sides. 

 Leaves not silvery. 

 Stem leaves linear. 



Stems rough-pubescent. 

 Stems glabrous to villous. 

 Heads 3''-i'' broad. 

 Heads 4^^-6^^ broad. 

 Stem leaves lanceolate. 



Heads not one-sided on the branches. 

 Stems glabrous or nearly so. 

 Kays violet. 

 Rays white. 



Rays 3''-4'Moug. H. 



Rays 2^^-3'Mong. 15. 



Stems finely canescent. 16. 



Heads strongly one sided on the branches. 



A. laevis. 

 A. concinnus. 



9. A. sericeus. 



10. A. exiguiis. 



11. A. parviceps. 



12. A. ericoides pilosus. 



13. A. salicifolius. 



paniculatus. 

 Tradescanti. 

 3Iissoiiriensis. 



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°-4°high: 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- 



