210 PROPAGATION. 



growing stocks ; of course the junction is always 

 apparent, and sometimes extremely dissimilar. This 

 seems to be owing to the unequal character of the 

 cellular and vascular fabric, as Fig. 52. 



There is a free intercommunication of the juices ; 

 but the specific difference of the ligneous structure 

 causes the disparity in the annual accretions. So with 

 respect to a graft of a dwarfish or slender-growing 

 species inserted in one of more vigorous habit, as the 

 Daphne Cnebrum on the D. Laureola, the contrary 

 effect takes place ; while the scion puts forth its atte- 

 nuated branches and feeble stem, that of the stock is 

 incrassated to twice the size. 



The sap-vessels on the bark and wood of both graft 

 and stock being numerous, can hardly miss coming 

 in contact when so united ; and the prompt inter- 

 junction of the cellular matter anastomoses the whole 

 together. On examination of the grafted part of a 

 stem of several years' growth, by cleaving it perpen- 

 dicularly, (Fig. 52,) or cutting it transversely, we see 

 that there is an intimate union between the layer of 

 wood, which was about to be formed when the opera- 

 tion was performed, and of all the subsequent formed 

 layers of both ; but between the wood of the graft and 

 stock which was formed before the performance, 

 although closely and soundly adhering to each other, 

 there is a visible juncture, marked by a brown -coloured 

 line where the two surfaces made by the knife were 

 joined. The union of these is, however, no more 

 than a simple adherence by means of secreted sap 



