CHAPTER XXXIII 



WEEDS 



409. Plants compete with each other. It happens that 

 some of the competitors are specially useful to man, and 

 he endeavors to protect them; and in protecting them he 

 destroys the plants that tend to crowd them out. Certain 

 plants have the habit of occupying places that are desired 

 for other uses. A weed is a plant that is not wanted. 



410. Weeds, therefore, are of two general classes: those 

 that interfere with plants that man cultivates; those that 

 inhabit unoccupied and waste places. Cer- 

 tain kinds of plants are specially adapted 



to hold their own in such competition or to 

 invade open places; and these plants are 

 particularly known as weeds. But any plant 

 may be a weed, if it is out of place or is 

 not wanted. June-grass is a weed in a corn- 

 field, but not in a pasture or lawn. Dan- 

 delion and purslane are commonly regarded 

 as real weeds, yet they are sometimes culti- 

 vated for "greens," and they then become 

 a crop. When any crop is too thick, the 

 weaker and useless plants interfere with the 

 others and become weeds. Thus some of 

 the corn plants may be weeds in a cornfield. 

 If one were growing a forest of maples, 

 other trees might be weed trees. 



411. The plants commonly known as 

 weeds have the power to distribute them- 

 selves and to persist, otherwise they 



p (241) 



408 



Common white 

 pigweed. C h e n o - 

 podium album. 



