IN THE FIELD 



198 



1. The Wild Mustard. 



This is one of the most troublesome weeds in some pa.rts 

 of Minnesota and Wisconsin. It has been introduced from 



FIG. 40. WILD MUSTARD. Brassica Sinapistrum. 

 Leaves, seed pods, and flowers. About one-half natural size. 



Europe. In some Minnesota counties, where flax has been 

 grown extensively or where the farmers have been care- 

 less, the fields are infested with it almost beyond hope 



