Epidermis 



.Cortex 

 ^Phloem 

 y-Xylem 



-Bark 

 -Wood ray 



Innual ring 

 -Pith 

 Pruned 

 branch 



rk bark 



Cortex 

 Phloem 

 -Xylem 

 -Pith 



Wood ray 

 'Cambium 



Cork bark 

 Phloem 

 'ambium 



Summer wood 



ing wood 

 nnual ring 

 rptTFood ray 



FIG. 12. The structure and growth of a tree 



A, diagram illustrating the gross anatomy of an oak tree in long section. Note 

 the relation of the annual rings, the junction of the branches with, the main trunk, 

 and the covering of pruned branches ; B, transverse sections of the tree shown in 

 A, at three levels. The figures in B are designed to illustrate the early, or pri- 

 mary, structure (a) and the secondary changes (b, c). 



