108 



THE APPLE TREE. 



the trunk indicates the age of the tree. They also show that 

 the wood grows externally, for the new layer is deposited 

 outside the old wood next to the bark. In other words, the 

 mode of its growth is exogenous (exo, outside, genao, I grow). 

 Compare the growth of the Palm (p. 225). 



PIG. XXVII. Flowering branch of Pyrus Mains : 1, section of a flower ; 2, sec- 

 tion of the ovary ; 3, section of the fruit (apple) ; 4, a seed ; 5, 6, sections of same ; 

 7, the embryo. 



