146 STATE HORTICULTURAL SOCIETY. 



first season; the next season the graft not only continued its rapid growth, 

 but the entire tree appeared to revive and send out new and vigorous 

 shoots. My theory in this case may not be a correct one, but I believe 

 that the cause of this change in the old tree was owing to the demand 

 which the new graft made upon the roots for plant food; they, in turn, 

 received materials for their extension. The supply which was gathered 

 and sent forward, not being all absorbed by the graft, was forced into the 

 old branches, increasing the size of their leaves, thereby causing a reaction 

 in the entire tree." 



A writer in the Transactions of the Massachusetts Horticultural Society 

 for 1879, page 18, said: " When part of a large tree is cut off and grafted, 

 the scions receive from the remaining limbs, through the cambium layer, 

 elaborated sap which overcomes the scion, but this is impossible when the 

 whole top of a little tree is cut off and grafted. " 



W. M. Paul of England, in the Gardeners' Chronicle, 1873, page 681, 

 says: "Where plants are united and both allowed to grow even out of the 

 same stem there is a change. I know an example of a camellia united in 

 that way, a Saccoi nova inarched into a large, semi-double. The first 

 named variety opened its centre every year, and bore the color of the 

 latter, and. was consequently of less value till after it [the latter] was 

 headed down, when the good variety toek on its natural form. The leaves 

 [of the stock] in this case must have had the power of altering the 

 character of the flowers" [of the graft]. 



CONCLUSION. 



In the foregoing pages there is abundant evidence that the stock and 

 graft influence each other's growth in many ways. Seldom, however, is it 

 shown that the recorded observations were based on direct experiments 

 undertaken for the particular purpose of determining the modifying influ- 

 ence of the stock or graft. Certain of the statements made are contra- 

 dictory; and if we would come to any conclusion in the matter, some of 

 the testimony must be rejected. In at least a few cases the changes said 

 to have been observed were evidently imaginary or due to other causes 

 than grafting. As these cases appear to form but a small proportion of 

 the whole, and as it is of some interest to know what beliefs are held, 

 I have not excluded testimony simply because it seemed unreasonable to 

 me. There is need of careful and extended experiments to fully settle 

 many of the points involved, and the writer hopes to contribute something 

 to this end in the future. A careful study of existing evidence seems to 

 justify the following conclusions: 



1. Size and vigor. — The stock and graft each imparts to the other some- 

 thing of its own degree of vigor or lack of vigor. This influence is 

 greater the first year or two than afterward. If the difference in vigor is 

 great, both stock and graft may ultimately perish. The dwarfing which in 

 certain cases results from grafting does not always arise from a diminished 

 supply of food, but often indirectly from earlier and more abundant 

 fruitfulness. 



2. Form. — The alterations in the forms of trees, as the result of graft- 

 ing, arise mainly from increased or diminished vigor. This probably 

 applies also to alterations in the form of the roots, vigorous roots having 

 larger, longer, and fewer branches than feeble ones. Many of the 

 observed changes, however, in the form of the roots of grafted trees, are 



