DESCRIPTIVE MANUAL 



395 



Fig. 231. Perennial Sow Thistle (.SonofMs arvensis). Plants with 'brlsrht yel- 

 low flowers, milky juice. Not common in Iowa. A difficult weed to exter- 

 minate. 



(Photographed by Colbum.) 



Fig. 231-A. Distribution of Perennial Sow Thistle. 



