STRUCTURE OF THE ROOT 83 



developed as in stems, the old root is covered by a band of bark not 

 unlike that of a woody stem. 



The stem, leaf, and root, as seen in ordinary Flowering Plants, have 

 now been described. In subsequent chapters the Plant-Body can 

 therefore be considered as a connected whole, and some idea gained 

 of its physiological position as a concrete living organism. Normally, 

 with its root in the soil and its shoot in the air, it acts as a sort of 

 intermediary between the two regions in which it lives. One phase 

 of the Botanical interest will be to see how the Plant plays off the 

 one medium against the other, drawing meanwdiile its nourishment 

 from both. Another phase is to follow the materials abstracted and 

 to see how they are used in Life, and how on the disorganisation of 

 the Plant after Death that material is finally restored to its original 

 source. Vegetation may thus be looked upon as an active factor in 

 that interchange and circulation of material which is constantly 

 taking place at the surface of the Earth's crust. 



