196 COMPOSITAE 



long, entire, hispidulous, rough-margined: involucral scales appressed or 

 spreading : rays 20-30, violet-purple, 4" long. Often common in bar- 

 rens in the southern part. September-October. 



7. A. laevia L. 2-3 high : leaves entire or serrate, rough-mar- 

 gined : involucral scales close, green-tipped : heads I/ broad : rays 15-30, 

 blue. Frequent in dry grounds throughout the southern part. Septem- 

 ber-October. 



8. A. concinnus Willd. Closely resembles the last but the plant is 

 taller and the leaves elongated linear-lanceolate. Dry woods, especially 

 around Dodson. September-October. 



9. A. sericeus Vent. l-2 high, glabrous : leaves oblong-lanceolate, 

 sessile, entire : involucral scales loose, spreading, caiiescent : heads 18 X/ 

 broad : rays violet-blue. Rarely found on rocky prairies near Lee's 

 Summit. August-October. 



10. A. exiguus (Fernald) Rydb. l-2 high, much branched: 

 leaves rigid, sessile, rough and ciliate-margined : heads very numerous, 

 3//_4// broad : involucral tips spreading : rays white, 10-20. Often 

 abundant in dry soil. August-October. 



11. A. parviceps (Burgess) Mackenzie & Bush, n. comb. l-3 

 high, glabrous, bushy-branched : leaves short-linear, acute, entire, rough, 

 with short very few-flowered branches in their axils : leaves of branches 

 scale- like : heads small, numerous, not crowded : rays 10-20, white, l x/ - 

 2 X/ long. Common on a low prairie one mile south of Dodson ; also at 

 Lake City and Courtney. September-October. (A. ericoides parviceps 

 Burgess. ) 



12. A. ericoides pilosus (Willd.) Porter. l-3 high, hairy : basal 

 leaves spatulate : stem leaves linear : inflorescence paniculate : heads 6 /x 

 wide : rays 15-20, white, 3" long : involucral scales conspicuously green- 

 tipped. Dry woods west of Lee's Summit. September-October. 



13. A. salicifolius Lam. 2-6 high : leaves lanceolate, rough, sessile, 

 thickish, sharply serrate : heads numerous, panicled, 8 // -12 // broad : rays 

 numerous, 3 /x -4 /x long, violet, rarely white. Common in open woods 

 throughout. August-October. 



Var. subasper (Lindl. ) A. Gray. Stems and leaves scabrous : inflores- 

 cence more contracted. In similar situations, but less common. 



14. A. paniculatus Lam. 2-8 high : leaves lanceolate, rough-mar- 

 gined, sessile, sharply serrate : heads as in the last, but rays white. 

 Very abundant in low grounds. August-October. 



15. A. Tradescanti L. Closely resembles A. paniculatus, but heads 

 only 5"-8" broad, and rays 2 // -3 // long In moist grounds near Shef- 

 field and Grain Valley. Common locally. August-October. 



16. A. Missouriensis Britton. l-3 high, puberulent : leaves spatu- 

 late to oblanceolate, sharply serrate above the middle, or entire, tapering 

 to a winged petiole at base or sessile : heads 4 // -7 // broad, terminating 

 short leafy branches or pauicled : rays white, \\"-%\" long. Very 



