WEEDS 



337 



but much also is expended for extra wear and tear of farm 

 implements and machinery and for the purchase of implements 

 which are only needed for contending with weeds. It is worth 

 while to notice that the labor expended in destroying weeds 

 is not all dead loss, as the loosening and turning over of the 

 soil is often of much use to the 

 growing crops. 



Aside from the damage which 

 they inflict on crops, weeds cause 

 much inconvenience and loss, as 

 they infest roadsides and rail- 

 road rights of way, and choke 

 up streams, canals, and irrigation 

 ditches. 



314. Where our weeds origi- 

 nated. 1 Among the most trouble- 

 some weeds in the long-settled 

 portions of the country about 

 half are of European origin 

 and several came from tropical 

 America and from India. Only 

 about 40 per cent are native 

 American species. 2 



Naturally most of the Euro- 

 pean weeds introduced into this 

 country have traveled rather 

 slowly inland from the Atlantic 

 coast. Some species, like the 

 common groundsel (fig. 19), 

 chicory, butter and eggs, wild 

 carrot, and wild parsnip, are still much more common in the 

 maritime provinces of Canada and in New England than 



1 See the article "Pertinacity and Predominance of Weeds," in the 

 Scientific Papers of Asa Gray, selected by C. S. Sargent, Vol. II, Houghton 

 Mifflin Company, Boston ; also ft Farm Weeds of Canada," Second Edition, 

 Government Printing Bureau, Ottawa, Canada. 



2 Farmers' Bulletin 28, U.S. Dept. Agr. 



FIG. 244. The buffalo bur 

 (Solanum rostratum) 



This is a troublesome weed in grain- 

 fields. It is traveling eastward from 

 the Great Plains near the Rocky 

 Mountains. It is often distributed 

 by being blown about as a tumble- 

 weed. One sixth natural size 



