ACTION OP FLOWERS. 65 



gins to flower depends upon the presence in its sys- 

 tem of a sufficient quantity of secreted matter fit for 

 the maintenance of the flowers when produced. Un- 

 der ordinary circumstances, a considerable part of all 

 the nutritious secretions elaborated by the leaves are 

 expended in the production of new leaves ; but, after 

 a time, a greater supply is formed than the leaves re- 

 quire, and the residue collects in the system ; as soon 

 as the residue has arrived at the necessary amount, 

 flowers may begin to form.. If the sterile branch of a 

 tree is ringed,* it ceases to be sterile ; and this can 

 only be accounted for upon the supposition that the 

 secreted matter of the branch, instead of being con- 

 veyed away into the trunk and roots, is stopped by 

 the annular incision, above which it is compelled to 

 accumulate. If a tree that is unproductive be trans- 

 planted, it begins to bear ; in this case the operation 

 injures its roots ; sap is therefore less abundantly sup- 

 plied in the succeeding season to the leaves ; the 

 leaves are therefore less able to grow than they pre- 

 viously were, and they consequently do not consume 

 the nutritious matter lying in the branches, and which 



* One of the effects of ringing has been observed to consist in the 

 formation of numerous barren shoots below the wound, while fertile 

 shoots appear above it. This is conformable to the theory of the 

 formation of flowers being determined by a superabundance of 

 nutritious matter in a given plaee. The bark below the annular 

 excision is cut off from a supply of the sap elaborated by the leaves 

 above it ; and, at the same time, in consequence of the obstruction 

 of the wound to the ascent of the crude sap, an unusual supply of 

 the latter,is forced towards the buds in the bark below the wound; 

 which buds, being chiefly fed with crude sap, push forth into 

 branches and leaves, but bear no flowers. 



