528 Principles of Gardening 



of a branch on the perfect plant. The unlimited individuality 

 which the various transformations of the bud display, has been 

 by many authors extended to the normal bud itself. According 

 to this view^, the dicotyledonous tree consists of as great a num- 

 ber of single plants as there have been buds produced on it in 

 the course of time, and the union of all these forms a whole 

 which is nourished by one root. This view gives us a lively 

 representation of the creation of a tree; in reality, however, it 

 is not so applicable, as the bud itself can only be made to de- 

 velope itself as an individual by art. 



From the bud in a state of developement proceeds the forma- 

 tion of the young wood ; on which account Du Petit Thouars 

 called the cellular tissue (Faserzellen) and spiral vessels (Spiral- 

 rcihren), which extend from knot to knot as far as the root, 

 the roots of the bud, but considered the cells of the medullary 

 rays as forming the inner bark. To this Meyen objects that, 

 when, for example, a branch with I'ed wood is grafted on a white 

 one, the new ring of wood formed below the graft has the colour 

 of the stock ; that the spiral vessels are jointed ; and the cellular 

 tissue seldom extends from knot to knot entire, but that the 

 threads have their points obtusely truncated and rest upon others. 

 He explains it in the following way : " The sap descending from 

 the bud, in the inner bark, is deposited at the sides between the 

 wood and the bark, and is then congealed into a woody sub- 

 stance;" by which he denies that the bud has any immediate 

 effect in forming the wood, but acknowledges it mediately, as in 

 it is prepared the sap for the formation of the wood. The phe- 

 nomenon, therefore, of a branch deprived of its buds producing 

 no new layer of wood cannot be considered as an objection. 

 Still, from this explanation, the formation of the cellular tissue 

 and spiral vessels remains in obscurity; for though we find 

 everywhere parenchymal cellular tissue formed wherever the 

 descending sap is deposited, yet I know of no other case where 

 it has formed woody fibre, but this of the connexion existing 

 between it and the formation of the inner bark and the roots. 



As we further remark, that the formation of roots in cuttings 

 is always in intimate connexion with the formation of young 

 wood, which I shall advert to further in the practical part ; I 

 think myself justified in the conclusion, that the whole of the 

 young woody layer proceeding from the bud is analogous to the 

 formation of its roots ; but with this difference, that, while the 

 woody fibres of the young wood are united by the medullary 

 rays, in forming the roots they are separated from them, and 

 appear surrounded by the parenchymal cells of the medullary 

 rays. It hence appears, that the new layer of wood is formed 

 from the sap which, descending from the bud, issues from the 

 inner bark ; also that the cells of the medullary rays may be con- 

 sidered as a purely lateral formation of the layer of bark ; but 



