244 (SROWTH Of TREES. 



a part attached to each, capable of increase, and which draws 

 out like a telescope ; this increase is generally the usual distance 

 allowed to new shoots in every sort of plant between bud and 

 bud, and of course varies according to the tree. When the 

 The shooting screw is formed, and the buds arranged in each, then the shoot 

 •f the screw, begins to push ; and here again great variety is discovered — in 

 some trees a quarter of a screw divides, and then runs up to 

 the end of the shoot, forming a long distance between the 

 buds in each new division, and thus continues to develop till 

 all the different links are expanded. In the horse-chesnut it 

 will separate into various pieces ; its leaves and buds growing 

 from each extremity, equally developing it both ways ; but it 

 may always be known which link, or which part of the screw 

 is drawing out, by the youngest leaves being in that place. In 

 the ash, nearly half the screv/ first shoots up to thetermination 

 of the new branch, and then continues to unfold that piece of 

 the screw, till it is all expanded ; it then completes the forma- 

 tion of its winter bud, and when that is once protruded in a 

 plant, it never shoots a piece beyond it that season. This is the 

 The new shoot case, I believe, in every forest tree : in all trees the new shoot 

 fh Id^ ^'^"^ differs from the rest, not only in the manner of placing its 

 leaves, but in the appropriate distance of the buds. In the 

 oak the leaves are alternate, and there is not half an inch dis- 

 tance between them : but in a new shoot two leaves come out 

 almost opposite, or within a quarter of an inch, and then pass 

 on a full inch before they recommence their former progress. 

 The first shoot of the elm is very different ; the leaves are all 

 twice the size of any other in the tree, and the distance of the 

 leaves is in proportion. Also the screw almost always deve- 

 lops below, at the part where the new shoot begins, and ver^ 

 rarely at the extremity of the branch : besides, nature esta- 

 blishes a curious difference between shooting from an embryo, 

 when a tree is first formed, and pushing its half-yearly branch in 

 spring and autumn. In the first, while yet in the seed, it forms 

 many buds, and while it is developing its seminal leaves, many 

 Shootinffwith* "'^°''^ ^^^ added to the number: from this preparation the branch 

 •ut screws. shoots at once, without waiting to arrange them in screws, be- 

 cause they then may be said to shoot, like an herbaceous plant, 

 from the root, which of course they can never do afterward ; 

 and must be protected by the sheath the leaves always lend to 



young 



