4 Department Circular 109, U. S. Dept. of Agriculture. 



pollen-producing flowers appear on the upper branches, an arrange- 

 ment which permits the pollen to fall upon the seed-forming flowers 

 much in the same fashion as with corn. After pollination, the pollen- 

 producing flowers wither and fall off. The root is stout and usually 



Fig. 1.— Cocklebur (Xanthium commune). 1, A single bur, showing the two hooked beaks at the 

 apex; 2, a portion of the plant, showing the burs and the branches of the male flowers above the 

 burs. 



unbranched, penetrating the soil frequently to a depth of a foot or 

 more. 



Cockleburs are sometimes confused with burdock because of the 

 resemblance of the burs, but they may be easily distinguished by the 



