228 THE PROPAGATION OF PLANTS BY MEANS OF STEMS 



form a perfect union. {Fig. 213.) However, only plants closely 

 related can be successfully grafted, for in the protoplasms of un- 

 related plants there are factors, probably differences in chemical 

 nature, which prevent the union of the cambiums. 



Fig. 209. — Cuttings of Sugar Cane. A, cutting, showing two nodes and 

 a bud at each node. B, cutting, showing a new plant which has developed 

 from a bud at the node. Adapted from N. A. Cobb. 



When grafting is successful, the cion becomes as closely related 

 to the activities of the stock as ordinary branches are. Through 

 the stock the cion receives water and mineral elements from the 

 soil, while the stock receives some of the foods made by the leaves 

 of the cion. However, with all of this close connection, the nature 

 of both stock and cion remains in most cases practically unchanged 

 and each, therefore, continues to produce fruit unchanged in type. 

 This feature is important for two reasons. First, it enables one 

 to combine the desirable features of two plants into one individual 

 where the desirable features, although remaining unchanged in 

 nature, may assist each other in functioning. Some fruit trees 

 bear delicious fruit, but on account of poor root systems or other 



