FIG. 3. The root system of the corn plant 



The soil has been washed away so as to show the quantity and spread of the roots, 



and, to some extent, the positions that they assume in the soil. Photograph by the 



United States Department of Agriculture 



FIG. 4. Two upturned spruce trees which grew upon a stony surface 



The entire root system spread over the rock did not provide sufficient anchorage 

 to hold the tree in place in time of a very heavy wind 



7 



