440 



EXPERIMENT STATION BULLETIN. 



Fig. 240 (209). 



Spiny-leaved Sow Thistle. Sonchus asper (L.) Hill. Chiefly smooth, except mar- 

 gins of leaves, juice milky, 30-90 cm. high; perennial; spreading by rootstocks and 

 seeds; leaves prickly to the touch, not true of the other species; flowers pale yellow. 

 Introduced from Europe. 



