320 composit'ae 



«-» Leaf-blades thin, prominently toothed. 

 Bracts of the involucre linear and obtuse or obtusish. 

 I<eaf-blades thin, rough : petioles mainly not winged. 



12. A. cordif alius. 

 Leaf -blades firm, smooth : petioles mainly winged. 



13. A. Lowrieanus. 

 Bracts of the involucre linear and acute, or subulate. 



14. A. sagiilaefolius. 

 b. Blades, or petiole-like bases of some of the cauline leaves cordate-clasping. 



15. A. undulatus, 



B. Basal and lower cauline leaves with relatively narrow blades, withjmore or 

 less contracted petiole-like bases but not cordate ; upper cauline leaves 

 with sessile or clasping blades. 

 Cauline leaves clasping by the more or less auriculate-cordate bases. 

 Stem rough-pubescent or hirsute. 

 Leaf -blades entire. 

 Leaves with sessile strongly cordate-clasping blades. 

 Stem rough-pubescent: involucre campanulate. 

 Inflorescence broad : leaves rough : stem relatively low. 



, 16. A. patens. 

 Inflorescence narrow : leaves soft : stem tall. 



17. A. phlogifolius. 

 Stem hirsute : involucre hemispheric. 18. A. Novae-Angliae. 



Leaves with slightly clasping bases. 

 Involucre hemispheric ; bracts glandular. \<). A. oblongifolius. 

 Involucre turbinate ; bracts hispid. 20. A. amelhystinus. 



Leaf-blades; at least those of the lower leaves, toothed. 



21. A. puniceus. 

 Stem glabrous or inconspicuously pubescent above. 

 Leaf-blades sharply serrate. 

 Leaves tapering to the base. 

 Leaf-blades mainly lanceolate to oblong-lanceolate, without petiole- 

 like bases. 21. A. puniceus. 

 Leaf-blades mainly oval or ovate, some of the lower ones with peti- 

 ole-like bases. 22. A. palulus. 

 Leaves abruptly contracted into broad petiole-like bases and often 

 dilated near the stem. 23. A. prenanthoides. 

 Leaf-blades entire or nearly so, an occasional coarse tooth sometimes 

 present. 

 Involucre campanulate. 

 Blades of the cauline leaves oblong to oval-lanceolate : inflorescence 



tending to a raceme-like panicle. 24. A. laevis. 



Blades of the cauline leaves linear or elongated-lanceolate : inflores- 

 cence tending to a corymb-like panicle. 25. A. concinnus. 

 Involucre hemispheric. 

 Bracts of the involucre linear-subulate : leaf-blades narrowly linear. 



26. A.junceus. 

 Bracts of the involucre linear : leaf -blades broader. 



27. A. Novi-Belgii. 

 Cauline leaves with merely sessile or essentially sessile blades. 



Leaves neither succulent nor fleshy. 

 Ray-flowers with violet ligules. 28. A. Radula. 



Ray-flowers with white ligules, or sometimes pink or purplish. 



