24 PROPAGATION. 



that it may not make too large a demand on the root for a sup- 

 ply of food. 



Budding may be done in tlie spring as well as at the latter 

 end of summer, and is frequently so performed upon roses, and 

 other ornamental shrubs, by French gardeners, but is only in 

 occasional use upon fruit trees. 



Influence of the stock and graft. 



The well known fact that we may have a hundred different 

 varieties of pear on the same tree, each of which produces its 

 fruit of the proper form, colour, and quality ; and that we may 

 have, at least for a time, several distinct, though nearly related 

 species upon one stock, as the Peach, Apricot, Nectarine, and 

 Plum, prove very conclusively the power of every grafted or 

 budded branch, however small, in preserving its identity. To 

 explain this, it is only necessary to recall to mind that the as- 

 cending sap, which is furnished by the root or stock, is nearly a 

 simple fluid ; that the leaves digest and modify this sap, forming 

 a proper juice, which re-descends in the inner bark, and that 

 thus every bud and leaf upon a branch maintains its individu- 

 ality by preparing its own proper nourishment, or organizing 

 matter, out of that general aliment, the sap. Indeed, according 

 to De Candolle,* each separate cellule of the inner bark has this 

 power of preparing its food according to its nature ; in proof of 

 which, a striking experiment has been tried by grafting rings of 

 bark, of different allied species, one above another on the same 

 tree without allowing any buds to grow upon them. On cutting 

 down and examining this tree, it was found that under each 

 ring of bark was deposited the proper wood of its species, thus 

 clearly proving the power of the bark in preserving its identity, 

 even without leaves. 



On the other hand, though the stock increases in size by the 

 woody matter received in the descending sap from the graft, yet 

 as this descends through the inner bark of the stock, it is elabo- 

 rated by, and receives its character from the latter ; so that, 

 after a tree has been grafted fifty years, a shoot which springs 

 out from its trunk below the place of union, will always be found 

 to bear the original wild fruit, and not to have been in the least 

 affected by the graft. 



But, whilst grafting never effects any alteration in the 

 identity of the variety or species of fruit, still it is not to be de- 

 nied that the stock does exert certain influences over the habits 

 of the graft. The most important of these are dwarfing, indu- 

 cing fruitfulness, and adapting the graft to the soil or climate. 



Thus every one knows that the slower habit of growth in the 



* Physiologic Vegetable, 



