184 



WEED FLORA OF IOWA 



Pig. 104. Yellow or Hop Clover (Trifolium agrarium). Along roadsides. Yel- 

 low flowers. 

 (Photographed by Colburn.) 



Low Hop-clover (Tri folium procumbens L.). 



Description. — A pubescent annual with spreading or ascending 

 stems; leaves of 3 leaflets pinnate, the lateral at a small distance 

 from the other, obovate, notched at the end; stipules ovate, short; 

 flowers yellow, persistent, becoming dry in age. 



Distribution. — Naturalized from Europe; common in eastern 

 states. 



Extermination. — Readily succumbs to cultivation. The seeds, 

 however, may retain their vitality for some time in the soil. Sow 

 clean seed in clean soil. 



