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 sidewise 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 tothe 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 
