'3 



have been put on since the bud was set. In this case, as with the 

 common graft, the layers of new growth are continuous, running from 

 top to bottom without any break at the plane of junction. 



If a successful bud graft of several years' standing is cut in two 

 along its axis we shall find almost precisely the same conditions as 

 we have already found in the ordinary graft. Although the annual 

 growth layers are continuous, we may sometimes find a line of de- 

 marcation visible to the naked eye. When this is examined under 

 the microscope, however, the distinction usually disappears to a con- 

 siderable degree, and the cells are found to run together indistin- 

 guishably. There is therefore no difference, from our present point 

 of view, between a bud graft and a long-cion graft. 



MECHANICAL STRENGTH OF THE JUNCTION 



There has always been a good deal of debate amongst horticultur- 

 ists as to the mechanical strength of a graft. Some have said that 

 the graft always presents a point of weakness in the tree. Others 



FlG. 9. Bud grafts 1 and 3 years old. showing continuous layers of young wood. 



