468 



BIOLOGY AND HUMAN LIFE 



two parts belong to different plants. Such growing together is 

 called grafting and is extensively utilized in horticulture (see 

 Fig. 191). The scion, or twig grafted upon the stock, produces 

 leaves, flowers, and fruit of its own kind, uninfluenced by the 



Fig. 191. Grafts 



A bud or twig of one plant is made to grow by means of nourishment supplied by the 

 root or stem of another plant. The root or stem supplying the nourishment is called 

 the stock; the bud or twig grafted on the stock is called the scion. The figure shows 



stem, bud, and root grafts 



character of the stock ; that is, the protoplasm determines the 



character of its products, rather than the food which it receives. 



In recent years a new application of grafting has been made 



in tree culture. Where orchard trees have been girdled (p. 120) 



