156 



The Stem— Strictures [April, 



a tree is pruned in autumn and winter, the whole supply of nour- 

 ishment goes to the remaining branches, while if pruning be done 

 after the sap starts, the nourishment is partly lost. 



If we would prune to induce fruitfulness, as we often do when a 

 young tree is too luxuriant, forming few or no blossom buds, it may 

 be done by pinching in the growth during the summer or late in the 

 spring, thus checking its energies in producing wood, and directing 

 them to the forming of fruit buds. This is often successfully done 

 by root pruning, thus cutting off an extra supply of nourishment 

 from the earth. 



GRAFTING. 



This operation consists of inserting a scion taken from one tree, 

 into the stem of another, in such a manner that they unite, and the 

 inserted scion bears its own fruit. Grafting may be performed in 

 many different ways, some enumerate over forty. The most impor- 

 tant points are to apply the inner bark of the stock and of the graft 

 precisely to each other, and to keep them in such position until a 

 union takes place, excluding, during this process, the air and mois- 

 ture from without. Grafting can only succeed when it is performed 

 between vegetating parts. Thus, wood can not be grafted, nor even 

 alburnum. Grafting, or union of plants, can take place only be- 

 tween plants of the same species, species of the same genera, or 

 lastly, genera of the same family ; never between individuals belong- 

 ing to different natural orders; for example, the peach may be grafted 

 upon the almond, the apricot on the plum, but the operation would 

 not succeed between the peach and pear. It being necessary that 

 there should be a kind of agreement or similarity between the sap 

 and sap vessels of the two individuals before the union of the graft 

 can be effected. The union is effected through the cambium layers. 

 When the wound of a graft is examined about a fortnight after the 

 operation, a thin layer of small greenish granulations, dispersed in 

 a viscid fluid, may be seen between the two parts that have been 

 brought together. These granulations — the rudiments of vegetable 

 organization — are produced by the cambium which becomes solidi- 

 fied and organized. Of the various modes of grafting and their 

 peculiar advantages, they arc so well understood as not to demand 

 here a description. Besides, mere descriptions never answer the 

 purpose; grafting is a mechanical operation, and must be performed 

 under instructions to succeed. Tongue grafting, or whip grafting, 



