PART V 



WEEDS OF THE FARM. 



CHAPTER XLII. 



WEEDS: GENERAL. 



I. Although it is difficult in a few words to explain what a weed 

 is, so far as the farmer is concerned it may be described as any 

 plant whose growth interferes with that of the crop to which the 

 soil for the time being is devoted. The idea of uselessness is 

 always present in the mind when weeds are being spoken of. 

 The plants themselves, however, may be those which are 

 ordinarily grown on a farm, but the fact of their occurrence 

 where they are not needed condemns them. Very often shed 

 seeds of oats and black mustard make their appearance in a crop 

 to its detriment, and tubers from a crop of potatoes or artichokes 

 left in the ground may occasion trouble, and require to be treated 

 as weeds in the following year. Useful fodder grasses may overrun 

 and reduce the value of a clover, sainfoin, or lucerne ley. 



Cultivated plants out of place have been named relative weeds, 

 in contrast with those plants which possess no apparent value to 

 the farmer and are injurious to all crops among which they occur. 

 The latter are termed absolute weeds, and to this group belong 

 thistles, bindweed, docks, poppy, and a very large number of 

 native wild plants, which, although in Nature's great collection 

 of living things no doubt perform some useful work, are never- 

 theless, from the farmer's special point of view, practically 

 without any appreciable value. 



2. Their injurious effects. — There are a great many ways in 



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