MICHIGAN" STATE POMOLOGICAL SOCIETY. 197 



of the habits of the growing top. In the case of grafting slow 

 growing varieties upon a very strong growing stock, or upon a 

 full grown tree, the large supply of sap food will stimulate the 

 grafts to put on a much more vigorous growth than when 

 undar ordinary circumstances, but in such cases the top will 

 in a few years return to its natural habit of slow growth ; 

 slender or crooked branches, as the original habits of the vari- 

 eties may have been. 



The greater the dissimilarity between the stock and graft, 

 the more difficult and slow will be the passage of the prepared 

 material for the formation of new wood, from the graft to the 

 stock, and as a consequence an excess of this wood-forming 

 substance is retained in the graft, and is there formed into 

 woody growth and fruit buds, while the stock itself receives 

 only a limited supply of material for new growth. 



This principle is employed in the production of Dwarfs. 

 The excess of nourishment partly retained above the stock, 

 expends its forces in forming fruit buds and in bearing fruit, 

 when, had there been no disagreement between the stock and 

 graft this prepared plant food would have passed into the stock 

 and its roots, thereby enlarging and invigorating them, and 

 they, in turn, would have been able to furnish the top with a 

 full supply of crude material to be prepared for the formation 

 of new wood. 



These facts are known and made use of in the production 

 of dwarf trees. 



Grafting and budding on dissimilar stocks causes an obstruc- 

 tion in the flow of matured sap from the graft to the stock. 

 This excess of nourishment expends its forces in developing 

 the young trees, in forming fruit buds, and in the early bearing 

 of fruit ; but the stock, not receiving an adequate supply of 

 food for the full formation and extension of its roots, is 

 checked in its own growth, and, as a consequence, can furnish 

 only a moderate supply of crude sap for the leaves to digest, 

 which is again largely devoted to the production of fruit 



