92 INTRODUCTION TO BOTANY 
living plant so that the cambium layer of each will be in con- 
tact with that of the other (fig. 75). The plant into which 
the stem is inserted is called the stock, and the portion of 
shoot which is set into the stock is called the scion, or graft. 
There are many kinds of woody plants which may readily be 
grafted, but the process is of practical im- 
portance mainly for the grower of apples 
and pears. Various plans are adopted in 
different fruit-growing regions. One of the 
commonest methods for the propagation of 
apples is root grafting. Seedling trees a year 
old are dug in the autumn and the roots 
grafted with one-year-old scions of desired 
varieties of apple trees, each cut to the 
length of about six inches. The grafted 
roots, wound about the joined surfaces with 
waxed cord, are packed in sand in a cool 
and not too dry cellar and left until spring. 
By that time the cambium layers of root 
and scion have united and the roots are 
ready to plant. Zongue grafting is practiced 
in the spring either with young seedlings 
or with twigs of larger trees (fig. 75). Top 
grafting consists in cutting off limbs one or 
Fie. 75. Grafting 
At the left, scion and i i: eae 
stock are shown ready two inches in diameter, splitting for a short 
a a ae distance the portion remaining attached to 
and ready to be cov- the tree, and inserting at each part of the 
ered with grafting gnlit, where it crosses the cut surface, a 
wax. After Percival i : 
small scion, and then completely covering 
all exposed parts with grafting wax. Root grafting has the 
advantage of resulting in a tree with trunk and branches 
wholly of the desired variety of apple. Tongue grafting of 
small branches does not interrupt the growth of the tree and 
is done with very little trouble. Top grafting is mainly 
resorted to in order to renew old trees that are not bearing 
the desired variety of apple. 
