(60) 



5. Troximon. — Pappus capillary. Bristles 

 deciduous singly, not in a ring. Apex 

 of akenes rostrate; costse smooth. 



6. Taraxacum. — Pappus capillary. Bristles 

 persistent. Apex of akenes elongated, 

 rostrate; cost^ roughened. 



7. Sonchus. — Akenes flattened, not ros- 

 trate. Pappus silky, white, 



8. Hieracium. — Akenes terete, not rostrate, 

 Pappus brittle, discolored. 



B. Flowers tubular. 



a. Receptale naked. 



aa. Branches of the style club-shaped. 



1. Adenostyles. — Involucre 1-seriate. 

 Branches of the style filiform. Pappus 

 copious, silky, white. 



2. Bulbostylis. — Involucre imbricate, 2-3 

 seriate. Branches of the style filiform. 

 Pappus copious, silky. 



bb. Branches of the style flat and tipped 

 ivith an aj^pendix. 



aaa. Paiis of pappus oo. 



1. Bigelovia. — Involucre imbricate. Pap- 

 pus 1-seriate, capillary, brownish at ma- 

 turity. 



