On the Origin avd Formatiofi of Roots. 33 



thfough the hark ; and any body which contains much mois- 

 ture be applied^ numeroas roots \vill soon be emitted into it 

 immediately above the decorticated space, but never imme- 

 diately beneath it : and when the alburnum in the decorti- 

 cated-^paces has becortie lifeless to a considerable depth, 

 buds are usually protruded beneath, but never immediately 

 above it, apparently owiitg to the obstruction of the ascend- 

 ing sap. The roots, which are emitted in the preceding case, 

 do not appear in any degree to differ from those vvhich de- 

 scend from the radicles of generating seeds, and both appa- 

 rently derive their matter from the tluid which descends 

 through the corticail vessels. 



ihere are several varieties of the apple tree, the trunks and 

 branches of \Vhich are almost covered with rough excres- 

 cences, formed by congeries of poiilts which would have 

 become roots undef favourable circumstances ; and such 

 varieties are always very readily propagated by cuttings. 

 Having thus obtained a considerable number of plants of one 

 of these varieties, the excrescences began to form upon their 

 stems when two years old, and mould being then applied to 

 them in the spring, numerous roots were emitted into it 

 early in the summer. The mould was at the same time raised 

 round, and applied to, the stems of other trees of the same 

 age and variety, and in every respect similar, except that the 

 lops of the latter were cut off a short distance above the 

 lowest excrescence, so that there were no buds or leaves 

 from which sap could descend to generate or feed new roots ; 

 and under these circumstances no roots, but numtious buds 

 were emitted, and these buds all sprang from the spaces and 

 points, which under different circumstances had afforded 

 roots. The tops of the trees last mentioned, haviniT been 

 divided into pieces of ten inches long, were planted as cut- 

 tings, and roots were by these emitted from the lowest ex- 

 crescences beneath the soil, and buds from the uppermost 

 of those above it. 



I had anticipated the result of each of the preceding expe- 

 riments ; not that I supposed, or now suppose, that rcots 

 can be changed into buds, or buds into roots ; but I had 

 before proved that the organization of the alburnum is better 



Vol. 31. No. 13 3. Juli/ lbU9. C calculated 



