AGRICULTURAL BOTANY 



149 



form flower buds for the next year's growth. As the dry season often 

 occurs in midsummer, trees suffer a natural check in the reduced amount 

 of moisture furnished. An abnormal check to growth may be given 

 by pinching off the terminal buds or by cutting off the ends of the 

 roots. After the tree is in vigorous growth in the spring, an otherwise 

 barren tree may be forced to bear fruit by ringing, which obstructs the 

 downward flow of the sap to the roots. The same result may be pro- 

 duced by violently twisting the branch which it is desired should bear 

 or by simply bending it or tying it in an unnatural position. These 

 harsh measures probably shorten the life of the tree by cutting off some 

 of the normal food supply of the roots. 



It is of interest to the farmer to know how to increase 

 the growth of flower buds, inasmuch as his crop of 



in 



FIG. 72. Buds. 



IV 



I, Pottawattomie plum: in each group the central bud is a. leaf bud; the two outer buds 

 are flower buds. II, European plum; B, young wood; A, wood of preceding year; 

 S, flower spurs. Ill, Morello cherry; B, young wood; A, wood of preceding year; 

 F, clusters of flower buds. IV, apple : leaf buds. V, apple : F, flower bud. 



