GROWTH OF STEMS 
271 
fungi by a layer of wax. Usually a twig from a mature tree 
(the scion) is grafted upon the young stem of a seedling or on 
an inferior tree (the stock), producing fruit several years 
earlier than the seedling tree would. One can be sure, too, of 
obtaining the fruit wanted. If twigs from several kinds of 
trees be grafted upon a “ scrub ” tree, each twig will bear its 
own kind of fruit. At the same time the quality of the 
fruit on the tree’s own 
branches will be greatly 
improved. The pome 
fruits, drupe fruits, and 
citrus fruits are usually 
grafted. Greenhouse 
roses, azaleas, and other 
plants are propagated in 
this way. Budding is a 
process similar to graft¬ 
ing except that a bud is 
slipped into an incision in 
the bark, instead of a 
twig being inserted into Figure 259. -Whip OR Tongue Grafting. 
the end of a branch. In b the branch has been cut ex P ose 
. , , cambium in two places. In 2, the scion 
Layering IS a method been cut to fit the branch. In 3, the 
of obtaining new plants scion has been laid in place. In 4, the 
by covering a branch scion has been tied t0 the stock * In 5) the 
.,. . ,. J wax has been applied. 
with earth some distance 
from its tip. When roots form, the branch is severed from 
the main plant and transplanted. Roses, grapes, and 
currants are propagated by layering. All these methods 
are artificial, and seldom found in nature. 
Other plants propagate themselves by stems naturally, as 
the strawberry, which puts out long, leafless branches called 
stolons or runners, each stolon having a bud on the end which 
takes root when it finds favorable conditions, especially 
contact with the soil. When a new plant is well established 
