ANALYTICAL KEY TO G EX ERA OF COMPO SITAE. IO43 



PAGE 



k Leaves very large, reniform or orbicular, basal Petasites 102 1 



hh Leaves smaller, cauline, and basal. 

 i Heads 6-35 mm. broad; rays mostly longer than the diameter of 



the disk Erigeron 966 



it Heads 4 mm. broad; rays not longer than diameter of disk. 



Leptilon (in Erigeron) 969 

 ggg Involucral bracts in 3-5 series. 

 h Involucral bracts firm; rays few, white; leaves spatulate, linear, or 



obovate, nearly or quite entire Sericocarpus 945 



hh Involucral bracts membranous. 

 * Pappus distinctly double; inner bristles long, outer shorter. 

 j Leaves lanceolate, ovate or obovate; rays white. 



Doellingeria (in Aster) 970 



jj Leaves narrowly linear; rays violet Ionactis (in Aster) 971 



ii Pappus single. 



j Disk-flowers turning red, purple, or brown Aster 946 



;; Disk-flowers permanently white; leaves subulate-spatula te, 



crowded, rigid Leucelene 965 



