FULL-GROWN PLANT AND ITS PARTS 09 
While plants need a great deal of water a great 
many kinds can thrive much better where the soil. is 
moist, not wet. Most of the cultivated plants and 
many flowers and trees do better in well-drained land. 
Perhaps you have seen how small and yellow patches 
of maize or wheat look in the low and wet parts of a 
. field. This is because there is too much water in soil 
and not enough air. On the other hand, there are a 
few trees and many other plants which thrive better 
in wet sou, or even in the water. It has been the 
habit of the parents and forefathers of such plants to 
live in these places, so they naturally follow in this 
habit. 
How the roots and root hairs do the work of absorb- 
ing the water from the soil can be understood by the 
study of Chapters XI and XII. 
