WEEDS OF GARDENS AND FIELDS 39 



dry out, until finally they are strong enough to cling to the 

 hair or fur of any passing animal. 



Fortunately the Cocklebur spreads and multiplies only 

 through its seeds, so that it is comparatively easy to keep 

 in check in cultivated fields by means of clean culture con- 

 tinued late in the season. 



POTATO FAMILY 



The Horse Nettle is a perennial weed native to the 

 southeastern region of the United States, whence it has 

 gradually spread westward. Its general resemblance in 

 leaf, flower, and fruit to the common potato shows its re- 

 lation to that plant. The two belong to the same genus 

 Solanum. The rough, prickly plants attain a height 

 of from one to two feet, bearing good-sized oak-like downy 

 leaves, with long spines projecting from the midrib on 

 both the upper and the lower surfaces. The flowers are 

 white or purple, and develop into round yellow berries. 

 The latter are composed of a pulpy substance in which 

 many small seeds are embedded. These seeds are dis- 

 tributed by birds. 



Besides the seeds, the plant spreads and reproduces by 

 slender rootstocks that penetrate the soil in all directions 

 and live from season to season. These make the Horse 

 Nettle a difficult pest to subdue. Clean cultivation and the 

 eradication or starving out of the rootstocks are the best 

 methods. 



Like the Horse Nettle, the Buffalo Bur is a native of 

 America, having originally developed upon the plains of 

 the far West, where its burs became entangled in the hairy 

 fur of the wandering buffaloes. Since the advent of the 

 white man, the plant has spread eastward, until now it is 

 found in many regions throughout the country. Like the 



