28 LEAF-BUDS. 



tion can never be calculated on ; and form no 

 part of the science of cultivation. 



The cause of the formation of adventitious 

 leaf-buds is unknown. 



From certain experiments it appears that 

 they may be generated by sap in a state of 

 great accumulation and activity. 



Consequently, whatever tends to the accu- 

 mulation of sap in an active state may be 

 expected to be conducive to the formation of 

 adventitious leaf-buds. 



When a hard woody plant is cut down after 

 transplantation, adventitious leaf-buds will start 

 from all parts of the stem. They originate and 

 are pushed out from the centre, and are caused 

 by the accumulated sap. 



The leaf-bud and the flower-bud are the 

 same in the earliest stage of their organization, 

 but soon after, the change takes place which is 

 visible in most fruit trees as soon as the sap 

 begins to flow. 



The determination of these buds to leaf or 

 blossom-buds, no doubt depends on the quantity 

 and quality of the sap stored up during the 

 winter. When excessive vigor is produced in 

 trees, it is favorable to the production of leaf- 

 buds, and consequently of wood. On the con- 



