PLANTS IN THEIR RELATION TO HUMAN WELFARE 153 



cloth, a sooty mark is left. The damage done by smuts is very 

 considerable. In case of the corn crop alone it has been estimated 

 that a yearly loss of 20 per cent of the crop, or $20,000,000, is caused 

 thereby, and in the other cereal crops the loss is even greater. It 

 should be mentioned in closing this discussion tha.t the rusts and 

 smuts are only two of a large number of fungous diseases that affect 

 plants. 



