VASCULAR PLANTS. 41 



70. Malacothrix, DC. 



Receptacle flat, naked. Akenes truncate: 

 pappus 1-seriate; bristles, scabrous silvery, de- 

 ciduous in a ring. 



0. flowers yellow, purple, white. 



71. Troximon, Nntt. 



Involucre imbricate. Akenes linear; apex 

 contracted; pappus co-seriate; bristles silky, 

 not deciduous in a ring. 



0. 21. flowers yellow, purple. 



72. Taraxacum. Haller. 



Involucre imbricate. Akenes contracted into 

 a long beak; pappus co-seriate; bristles white, 

 capillary, nearly persistent. 



11 . flowers yellow. 



74. Hieracium, Tourn. 



Involucre co-seriate, imbricate. Akenes ter- 

 ete, with a thin, crenulated ring at the apex; 

 pappus l=seriate, capillary. 



U . flowers yellow, orange. 



75. Sonchus, L- 



Involucre co-seriate, imbricate. Akenes com- 

 pressed, truncate; pappus co-seriate, capillary; 

 hairs in fascicles and soft. 



0. If flowers yellow. 



