How Plants Live 29 



has a greater spread than the parts which reach out 

 into the air. A small plant of the garden radish with 

 leaves scarcely 2 inches long may have roots that go 

 down to a depth of 6 inches. The roots of the corn 

 plant have been traced to a depth of 6 feet 9 inches, 

 and to a spread of 7 feet 3 inches side wise from the plant, 

 and the roots of an old alfalfa plant have been found 

 at a depth of 12 feet 6 inches in the. soil. Studies have 

 been made which show that the roots of a wheat plant, 

 if placed end to end, would extend to a distance of 500 

 to 600 yards; and it is said that the roots of a large 

 pumpkin plant thus placed would extend to a distance 

 of 15 miles. 



The work of the roots. Of what use is this great net- 

 work of roots to the plant? The roots anchor the plant 

 in place, and they take in from the soil the water and the 

 minerals that the plant must have for its life and growth. 

 One of the chief reasons why plants must not be crowded 

 in planting is that they require much room underground 

 for their roots to develop, so that they can obtain the 

 supplies of water and minerals that the plant needs. 



The work of the leaves. Every important organ or 

 part of a plant or animal has a use. What do the leaves 

 do for the plant? 



(1) The principal work of the leaves is to make food for 

 the plant. In the cells of the leaves there is a green 

 coloring matter called chlorophyll, and through the action 

 of this, sugar is built up when the sunlight falls on the 

 leaves. This process will be discussed more fully in a 

 later chapter (page 47) . 



(2) The leaves help the plant also in securing a sufficient 



