S14 ON FACillTATING THE GROWTH Of ROOTS FKOM LA5f£SS. 



trees; apd one of these experiments appearing to point out 212 

 improvement in the propagation of such trees by laying, as do 

 not readily emit roots by that process, I send the following state- 

 ment, under the hope that it may be acceptable to the Horti- 

 cultural Society, 

 Sap descends I have cited, in a foroier communication*, apart of the 



fromthe leaves evidence, upon which! have inferred, that the sap of trees 



through the ■< , -r , 



bark. descends from their leaves through the bark j and I shall 



here only observe, in support of this opinion, that, if a piece 

 Proof of this, of bark be every where detached from the tree, except at its 

 upper end, it will deposit, under proper management, as 

 much, or nearly as much wood, upon its interior surface, as 

 it will if it retain its natural position j and that the sap which 

 generates the wood, deposited in the preceding circumstances^ 

 must descend through the bark, as it cannot be derived from 

 any other source. 

 Sap employed When a layer is prepared, and deposited in the ground, 

 tfon f ^'^^'"*" tl^ie progress of the sap, in its descent towards the original 

 roots JD a lay^ roots, is intercepted upon the side where the partially de- 

 ^* tached part, or tongue, of the layer is divided from ihe branch ; 



and this intercepted sap is, in consequence, generally soon era- 

 ployed in the formation of new roots. But there are many species 

 of trees, v/hich d« not readily emit roots by this mode of treat- 

 ment > and 1 suspected that, wherever roots are not emitted by 

 layers, the sap, which descends from the leaves, must escape 

 almost wholly through the remaining portion of bark, which 

 connects the layer with the parent plant, I therefore at- 

 tempted, in the last and preceding spring, to accelerate the 

 emission of roots by layers of trees of different species, which 

 do not readily emit roots, by the following means, having de- 

 tached the tongue of the layers from the branches in the usual 

 manner. 

 In layers Soon after midsummer, when the leaves upon the layers 



JI^Q^g'^j^^^^^jjpj had acquired their full growth, and' were, according to my 

 been formed, hypothesis, in the act of generating the true sap of the plant, 

 the layers were taken out of the soil ; and I found, that those 

 of several species of trees did not indicate any disposition to 

 generate roots, a small portion of cellular bark only having 



* Koriicultural Transactions of 1811; Journal, vol. XXXII. p. 350. 



issued 



