WEEDS 837 
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.! 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.” 
Naturally most of the Euro- Fic, 244, The buffalo bur 
pean weeds introduced into this (Solanwm rostratum) 
country have traveled rather This isa troublesome weed in grain- 
: : fields. It is traveling eastward from 
slowly inland from the Atlantic 4. Great Blainy tan the Boley 
coast. Some species, like the Mountains. It is often distributed 
common groundsel (fig. 19), ¥ eed. One sixth natural size 
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 
1See the article ‘‘ Pertinacity and Predominance of Weeds,’ in the 
Scientific Papers of Asa Gray, selected by C. 8. Sargent, Vol. II, Houghton 
Mifflin Company, Boston ; also ‘' Farm Weeds of Canada,** Second Edition, 
Government Printing Bureau, Ottawa, Canada. 
2 Farmers’ Bulletin 28, U.S. Dept. Agr. 
