12 



THE NURSERY AND THE ORCHARD. 



age. Thus we see that all parts of the organs of vegeta- 

 tion perform important offices in the growth of trees. 



The leaf, which is so essential to the process of vegeta- 

 tion, is represented in figure 3. It is composed of the 



frame-work to support the leaf and supply it with sap, 

 and the pulpy portion, which is composed of numerous 

 cells. By the aid of powerful microscopes, an almost in- 

 credible number of breathing pores are discovered 

 on the leaf, through which air and moisture pass 

 during vegetation. In addition to the buds, which de- 

 velop into leaves, in bearing trees, are found other buds, 

 the object of which is not the growth of the tree, but the 



Fig. 4. 



-Scick of buds, showing the leaf and fruit buds, 

 double and triple. 



single, 



continuation of the kind. These buds (a and b, fig. 4) ex- 

 pand into flowers, and, after passing through various 



