38 FARM FRIENDS AND FARM FOES 



reaches a height of ten or twelve feet, the simple stems 

 shooting straight upward and bearing along their ribbed 

 sides the large opposite three-lobed leaves with dentate 

 margins. The flowers are small and inconspicuous, being 

 borne in rows along the ends of the branches. The staminate 

 or pollen-bearing blossoms are above the pistillate or seed- 

 bearing flowers. The former are much more abundant 

 than the latter. Each of the pistillate flowers bears a 

 single seed. As the Horseweed is an annual, it may be 

 kept in check by thorough cultivation, or in untilled lands 

 by repeated mowings. There is often danger, however, 

 that during times of floods, bottom lands may be reseeded 

 from regions upstream. 



The Clotbur or Cocklebur is another pernicious weed of 

 the Sunflower family, which commonly develops late in the 

 season in gardens and cultivated fields. This plant is eas- 

 ily known on account of the peculiar burs, or seed heads, 

 covered with hooked spines. It is a low-growing annual, 

 attaining a height of but a foot or two, but 

 spreading over quite an area. The prin- 

 cipal stalks are tough and woody, and 

 bear the broad triangular leaves on the 

 ends of long, slender petioles. Two sorts 

 of flowers are borne by each plant, stam- 

 inate or pollen-bearing, which appear at 

 the upper end of the principal stalk, and 

 pistillate or seed-bearing, which develop 

 lower upon the same stalk. The pollen drops from the 

 former upon the latter, or is blown from plant to plant 

 by the wind, and thus fertilizes the embryo seeds. 



The bur really consists of a lot of bracts called, when thus 

 grown together, the involucre. As the seeds mature the 

 bur hardens, the hooked spines becoming stiffer as they 



