51 



coating or deposit of new growth on 

 the inside of the bark, and not a growth 

 or increase of parts already formed. It is 

 from the downward sap, since in branches 

 which are rung it ceases to be deposited 

 below the rings, but is continued annually 

 above the rings. 



De Candolle makes a distinction between 

 the outer skin or covering of the leaf and 

 annual shoot and that of all other parts 

 of the tree. He calls the outer covering 

 of the leaf and annual shoot the cuticle^ 

 and that of the rest of the tree the epi- 

 dermis. There is certainly a difference 

 between living skin and bark and dead 

 skin and bark, and it might be as well if 

 they had different names ; but if we give 

 the name of cuticle to the outer covering 

 of the living bark, it will be found, with its 

 green under layer of parenchyma or 

 " herbaceous envelope, " to extend over a 

 much larger space of our forest trees than 

 De Candolle assigns to it. There is nothing 

 D 2 



