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. 
Fic. 209. — Cuttings of Sugar Cane. A, cutting, showing two nodes and 
a bud at each node. 8B, 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 thecion. 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 
