PLANT INDUSTEIES 



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- 



FIG. 236. A properly pruned cherry tree, 

 the remaining branches full of flowers 



Photograph by the Michigan Development 

 Company 



sues, which causes a lodg- 



ment of food material 



and a consequent unusual 



growth on one side of the 



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. 



