COCKLEBUR. 



CONTENTS. 



Page. ■ Pa?e. 



Distribution of coctlebur 3 Uses 5 



Description 3 1 Eradication 5 



Damage 5 j 



DISTRIBUTION OF COCKLEBUR. 



THE cominon name cocklebur is applied to about a dozen species 

 growing on rich lands in practicall}' ail parts of the United 

 States except in the chy Southwest and the mountain areas. All 

 these species are contained in the botanical genus Xanthium. Unlike 

 nearly all of otu- troublesome weeds, most species of cocklebui' are 

 native. Other cominon names of cocklebur are clotbur, burweed, 

 bathurst bur, sheep bur, bm* thistle, buttonbur, hedgehog bm-, and 

 ditchbm\ Cockleburs are found along roadsides, fence rows, and 

 river banks, in waste places, farmyards, ditches, pastures, and fre- 

 quently in cornfields. They show a marked preference for moist 



places. 



DESCRIPTION. 



Cockleburs are so common that they hardly need to be described. 

 Practically all of the dozen species of cocklebur are troublesome. 

 The various species, with the exception of the spiny cocklebur 

 (XantMum spinosum), resemble each other closely and are similar 

 inhabit; hence, a general description will be sufficient. The spiny 

 cocklebur differs from the remaining species by the possession of 

 numerous 3-pronged yellow spines, each about an inch long, and 

 dark-green shiny leaves with conspicuous white lines and white 

 downy beneath. 



The cockleburs are all annuals, which means that they mature seeds 

 in a single season and then die. They produce a stout, rank growth, 

 usually from 1 to 4 feet high, although the height varies with con- 

 ditions: specimens a few inches in height may frequently bear 

 matm*e seed, especially in late fall. The outstanding characteristic 

 is the possession of spiny burs (fig. 1) about three-fourths of an inch 

 long, each containing two single-seeded chambers. The spines are 

 hooked, while at the top of the bur may be found in most species 

 two stout hooked beaks. In the common species of cocklebur the 

 leaves and stems are exceedinglv rouo:h. Two kinds of flowers are 

 formed, one producing pollen and the other forming seed. The 



185117=— 20 3 



