PLANT INDUSTRIES 317 
Grafting has long been practiced in horticulture (sect. 87). 
Parts of two individuals of closely related plants may be 
made to unite their woody tissues and grow as one plant. If 
one has a particularly desirable variety, he may insert small 
branches (scions) from it upon other less valuable related 
stock plants. The growing tissues (cambium) of the two, if 
united, will enable the 
pieces to grow together 
and continue to live essen- 
tially as one plant. In 
former practices the grafts 
were usually made above- 
ground and were probably 
made less effectively than 
they are now. If one visits 
an old orchard he is likely 
to see evidence of these 
grafts on the main stem 
or on the branches of old 
trees (fig. 235). The dif- 
ference in size of stock and 
scion in old grafts may be 
due to a difference in the 
natural rate of thickening 
of wood in the two, or to 
imperfect joining of tis- 
sues, which causes a lodg- 
ment of food material 
and a consequent unusual 
growth on one side of the 
Fic. 286. A properly pruned cherry tree, 
the remaining branches full of flowers 
Photograph by the Michigan Development 
Company 
graft. The advantages of grafting are great. Vigorous plants 
which produce poor fruit or scanty fruit may be used in ex- 
tending the production of especially prolific plants that produce 
fruit of unusually good quality. The same general principles 
apply to the culture of flowers as to fruit culture, and the 
possibilities are equally great. 
