286 PBACTIGAL BOTANY. 



Flowers whitish or purplish. Involucral scales 

 often purplish. Heads racemose-panicled, mostly nodding. 

 Stem leafy, Nabalus. 



997. Achenia beaked 998 



Achenia beakless. Pappus copious. Heads large. 



1000 



998. Flowers yellow. Beak of the achenia long. . .899 

 Flowers blue. Beak of the achenia short and 



thick. . Mulgedium. 



999. Heads large. A scape-bearing herb. Scapes 

 naked, hollow, bearing solitary large heads. Leaves pinnati- 

 fid, or i-uncinate, in a tuft. Outer involucre reflexed. 



Taraxacum Dens-leonis, Desf. 



{I)andelion.) 



Heads small. A leafy-stemmed herb. Lower 



leaves runcinate, upper ones lanceolate and entire. Heads 



in a long and narrow, naked panicle, 



Ijactuca elongata, Muhl. 



1000. Leaves all radical, lance-linear, long, woolly on 

 the margins, tufted. Scape simple, naked. Heads solitary, 

 large. Pappus rather rigid ; some of the bristles gradually 

 thickened toward the base. 



Troximou cuspidatmn, Pursh. 

 Leafy-stemmed weeds. Heads corymbed or umbel- 

 late. Pappus exceedingly soft. Leaves spiny-toothed, 

 usually runcinate-pinnatifid. Sonchus. 



{Sow-thistle.) 



