328 UPON GRAFTING THE WALNUT-TREE. 



No difficulties will henceforth, I conclude, occur in propagating varieties 

 of walnuts by grafting; and I am much inclined to believe, that different 

 species and varieties of oaks may be successfully grafted by the same 

 mode of management. 



The art of grafting our common fruit trees has been so long, and so 

 extensively practised, that it may reasonably be supposed to be, at this 

 late period, incapable of much improvement. But, nevertheless, I am 

 much inclined to believe that a good deal is still to be learned ; and it 

 would not afford matter of much astonishment to me, if it should be 

 proved that branches provided with blossom-buds might be transferred 

 with success from one side of the Atlantic to the other, to afford fruit in 

 the following season. The results of some experiments, which I made in 

 the last winter, and present spring, induce me to think this practicable, 

 though I am not yet prepared to decide that it is so. 



LXXIII ON THE BENEFICIAL EFFECTS OF THE ACCUMULATION OF 



SAP IN ANNUAL PLANTS. 



[Read before the HOUTICULTURAL SOCIETY, December 2,Qth, 1830.] 



BIENNIAL plants very obviously form in one season the sap, which they 

 expend in the following season in the production of blossoms and seeds ; 

 and the capacity of the reservoirs they form is greater or less, in pro- 

 portion as external circumstances are more or less favourable. Trees 

 also (as I conceive myself to have satisfactorily proved in the Philoso- 

 phical Transactions) generate in a preceding season, or seasons, the sap 

 which feeds, in the spring, their unfolding blossoms and young leaves. 

 Annual plants, on the contrary, possess no such reservoirs ; and they 

 must generate, in each season, all the sap which they can expend, exclu- 

 sively of the very small portion derived from the seeds from which they 

 spring. But by appropriate management, and creation of varieties, 

 annual plants may be made to accumulate, in one period of their lives, 

 the sap which they expend in another, with very great advantages to the 

 cultivator. 



The first produced female blossoms of the melon-plant, particularly of 

 the larger and superior varieties, do not often set ; and if they set, the 

 fruit they afford never attains as large a size, or as much excellence, as 

 the same plants, at a more mature age, would have given to it under the 

 same external circumstances. This, I imagine, arises not only from the 



