Top-working Fruit Trees 



149 



of the peach top, although the growth is by no means 

 stunted. So, in practice, we adhere largely to the inter- 

 grafting of different varieties of the same kind of fruit. 



To understand the principles underlying graftage, the 

 orchardist should know how the stems of our fruit trees 

 grow. He should understand that 

 growth in diameter takes place only 

 in a very small region between the 

 bark and sapwood. This part of 

 the stem is called the cambium. In 

 this thin layer of tissue the cells are 

 still active and capable of division, 

 while the activity of each succeeding 

 layer, on either side, grows less and 

 less. 



When the limb is split to insert a 

 cion, the cleft does not grow together 

 along its entire length, as some may 

 think. The cells in the cambium 

 may produce a growth that may, to 

 a certain extent, fill up the cleft and 

 cover over the stub, but the tissues of 

 the stock and cion make a true union 

 only where the cells of the cambiums 

 of the two come in contact. Figure 47 is a pen drawing 

 of a section through a stub, grafted two years before. 

 The stub was kerf-grafted, and shows that no union has 

 taken place between the woody tissues of the stock and 

 cion. The important point in grafting is to see that the 

 cambium layers of the stock and cion are matched at 

 some point. 



FIG. 47. Longitudinal 

 Section through a 

 Graft, showing that 

 Union takes Place 

 only around Outer 

 Edge. 



