284 Carduaceae 



perfect, pistillate or neutral; borne on a 

 common receptacle forming heads, sur- 

 rounded by an involucre of few to many 

 bracts in one or more series; calyx tube 

 attached to the top of the ovary, the limb 

 (pappus) of bristles, awns, teeth, scales, 

 crown-like or wanting; corolla tubular, usu- 

 ally 5-lobed or -cleft, the marginal flowers 

 frequently expanded into a ligule (ray) ; 

 when the ray flowers are absent the head is 

 said to be discoid, when present, radiate; 

 the tubular flowers form the disc. The largest 

 of all the families of flowering plants com- 

 prising about 760 genera and not less than 

 10,000 species, represented in the region by 

 the following: 



Anthers not tailed at the base ; heads rayed or rayless. 

 Style branches of the perfect flowers flattened, with 



terminal appendages. 

 Rays yellow or sometimes wanting. 

 Pappus double, the outer very short. 



Chrysopsis. 



Pappus simple; panicle compact. Solidago. 



Rays white, purple, or blue, rarely wanting. 



Involucral bracts in 1-2 series, narrow; rays 

 usually narrow and numerous. Erigeron. 

 Involucral bracts in 2-5 series; rays broader and 

 less numerous. 



