LUTHER BURBANK 



obviously lacks a good deal of complete satisfac- 

 toriness. For the moment, we perhaps must be 

 content to recognize in this another illustration of 

 the fact of communication between the different 

 parts of a plant, and of the harmony of purpose 

 through which the plant as a whole is made to 

 respond to the conditions of the environment in 

 the way that best meets its needs. 



But we are forced to recognize, through such 

 an illustration, a greater capacity for adaptation, 

 seemingly almost of a reasoned character, than we 

 are commonly wont to ascribe to the plant. 



The case of the tomato plant growing on the 

 potato roots, which so perverted the character of 

 the tubers that it supplied, has practical interest 

 for the plant breeder, and in particular for the 

 orchardist, because it demonstrates the effect of a 

 cion on the stalk on which it is grafted. Of course 

 the ordinary fruit tree does not develop a system 

 of tubers, and so it does not call for such a supply 

 of starch, for example, as that which the tomato 

 vine was induced to produce for the tomato roots. 

 But the root system of any tree requires nourish- 

 ment if it is to develop, and this nourishment, as 

 we have seen, must be supplied by the leaves of 

 the tree above it, even though the roots themselves 

 first collect part of the materials. 



It follows that the root system of any tree, while 



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