150 PLANT PROPAGATION 



and less distinct because of the development of other tis- 

 sues from it, the union of stock and cion is less sure. 

 At such seasons it is also more important to cover the 

 wounds to prevent or check loss of moisture from the 

 wounds. 



Wax (285) is usually used in outdoor work where the 

 wood itself is cut, but where only the bark is cut, as in 

 budding, it is necessary to bind only the bark firmly 

 over the bud and the wound until the union is complete. 

 Then the bindings must be cut to prevent strangulation. 



FIG. 133-STEAM TREE DIGGER IN BIG NURSERY 



Steam tree diggers are used only in the largest nurseries. They are very satis- 

 factory 



It is an erroneous theory that cleft grafts will die if the 

 adjacent bark of the stock is wounded seriously. The 

 bark serves scarcely a greater purpose than that of 

 protecting the tissues beneath. Cions often grow in the 

 almost total absence of the bark of the stock, provided 

 proper protection is given and the formation of new bark 

 thus encouraged. 



It is necessary that each cion have at least one sturdy 

 bud. As a rule, only mature buds, or those approximately 

 mature, are employed, though in herbaceous grafting 

 younger ones may be used. Cions may be inserted in 

 whole or piece roots, crowns, trunks, branches ; in fact, 



