Distribution of Plants in Nature 



303 



U. S. Forest Service 



Fig. 189. A view in a mixed mesophytic forest in eastern Tennessee. The prominent 

 trees in the picture are cucumber tree {Magnolia acuminata) and shagbark hickory {Carya 

 ovata). The deciduous forest formation approximates its best development in this region. 



plants from which they derive a food supply or from which they 

 obtain shade. 



One of the most familiar and important .t}^es of vegetation 

 is a forest. A mature forest consists of several stories or layers 

 of plants. The tallest trees form the canopy, and their leaves 

 are exposed to full sunlight. Below these trees there are usually 

 low trees and young trees that endure the shade, and are bene- 

 fited at least during the seedling stage by the more even temper- 

 ature and moisture conditions within the forest. Then there are 

 tall and low shrubs, some of which thrive in the forest because 

 of the accumulation of humus and the more constant water con- 

 ditions that go with it. On the floor of the forest are many her- 

 baceous plants and mushrooms of various kinds. Collectively, 

 all the low trees, the tall and low shrubs, and the herbs make up 



