GRAFTING 69 



known as the stock, and the resulting stems will bear the 

 wished-for sort of fruit. Often one species is grafted on another, 

 as the pear on the quince or the apple. Rarely trees differing 

 as much as the chestnut and the oak may be grafted together. 



FIG. 71. Two ash trees naturally grafted together 

 After Werthner 



Sometimes grafting comes about naturally by the branches of a 

 tree chafing against one another until the bark is worn away 

 and the cambium layer of each is in contact with that of the 

 other, or two separate trees may be joined by natural grafting 

 into a nearly cylindrical double trunk, as is shown in Fig. 71. 



