LUTHER BURBANK 



on the roots of a hardy stock, for the simple 

 reason that these roots have vigorous growth and 

 large capacity for imbibition of nourishment. 



But just as you cannot make a dog and cat 

 identical in constitution merely by feeding them 

 the same food, so you cannot cause a grafted cion 

 on your peach or pear or apple tree to conform in 

 shape or constitution to the stock on which it 

 grows merely by giving it the same nourishment 

 that the stock receives — for as explained above all 

 the most important functions of plant life are 

 carried on in the leaves. Thus we may have an 

 explanation of the fact that the graft governs 

 the root almost absolutely as to variety or 

 individuality, while the roots are purveyors for 

 the foliage. 



Sap-Hybmdism 



Nevertheless, I have had at least one experi- 

 ence in the course of years of practice in grafting 

 that seems to demonstrate the possibility of the 

 transfer from cion to stock of qualities that 

 transform in a very tangible degree the essential 

 characteristics of the plant. 



I refer to a case in which the twig of a purple- 

 leaved plum that I received from France was 

 grafted on an old Kelsey plum tree which stood 

 just at the corner of the vine-covered cottage on 

 my old place in Santa Rosa. 



[158] 



