WEEDS 



175 



ditions such as extreme dryness or cold. In the most un- 

 favorable situations, such as dry roadsides, they are able to 

 grow and produce seed. They are able to produce a great 





Importance of keeping down weeds another part of 

 experiment illustrated on page 174. Ground plowed, seed 

 bed prepared, weeds scraped with a hoe. Yield, 39.8 

 bushels. 



(Illinois Agricultural Experiment Station.) 



many seeds which have a strong vitality. Weed seeds may 

 remain dormant for several years but when favorable con- 

 ditions occur they germinate and develop into vigorous 

 plants. The large number of seeds is an advantage to the 

 weed because some of them are likely to fall in places where 



