LEAVES 



of the way through tubes which are dead. In such 

 regions the solutes are carried along in the water, the 

 movement of which is partly due to the fact that a 

 constant stream is kept up because of the evaporation 

 taking place at the surface of the leaves. 



Photograph by Henry G. Peabody. 

 Fig. 83. Conditions in a moist, semi-tropical forest. 



Habitat dependent on water supply. The conditions 

 upon the earth's surface favorable for plant life are 

 very diverse. Plants, as a result, become grouped 

 according to the conditions favorable for their growth, 

 forming so-called plant associations or plant societies. 

 These associations are determined by combinations of 

 conditions such as light, temperature, and water. 

 Perhaps the most important single condition is water. 



