306 MODE OF ITS GROWTH. 



doing it, and who has continued for a series of years to take 

 successive crops of wheat from the same exhausted fields. 



The peculiarity of this weed consists in the hard 

 covering with which its seed or nut is covered ; in the 

 time at which it comes up and ripens its seed ; and in the 

 superficial way in which its roots spread. The hardness 

 of its covering is such that " neither the gizzard of a 

 fowl nor the stomach of an ox can destroy it," and that 

 it w^ill lie for years in the ground without perishing, till 

 the opportunity of germinating occurs. It grows up very 

 little in spring, but it shoots up and ripens in autumn, 

 and its roots spread through the surface-soil only, and 

 exhaust the food by which the young wheat should be 

 nourished. A knowledge of these facts teach — First, 

 that unless care be taken to exclude the seed from the 

 farm, it will remain a troublesome weed for many years, 

 even to an industrious, careful, and intelligent cultivator. 

 In the second place, that spring ploughing will do little 

 good in the way of extirpating it, as at that season it has 

 scarcely begun to grow. Thirdly, that raising wheat year 

 after year allows it to grow and ripen with the wheat, and 

 to seed the ground more thickly every successive crop. It 

 is said that, when it has once got into the land, two or 

 three successive crops of wheat will give the pigeon- 

 weed entire possession of the soil. It is not, therefore, 

 the immediately exhausting effects of the successive crops 

 of corn alone which has almost banished the wheat- 

 culture from a large part of North America, where this 

 grain used to be produced in great abundance, but the 

 indirect or after consequences of such a mode of culture 

 in a considerable degree also. 



In a previous chapter, when describing the geological 

 structure and attendant agricultural character of western 

 New York, I have described the Marcellus shales as 

 forming the surface of the upland country, immediately 

 behind the wheat-region properly so called. These 



