66 



COURSE OF THE SAP. 



PT. II, 



It is clear that every part of the interior of this 

 branch — that is, of the woody part of it — which existed 

 when it was ringed in 1832 was in 1843 divided from 

 the exterior bark, and consequently from every bud 

 and leaf, by eleven annual sheaths or growths ; and 

 the upward sap, which nourished the bud, the leaf, 

 the shoot, and the fruit in 1843, must have been sup- 

 plied to them from the old liuged interior wood by 

 lateral transmission through the eleven newer annual 

 growths of wood. 

 The longi- It must, howcvcT, bc obscTvcd that the cone formed 

 pJth'Saan- at thc top of cach annual growth of wood is not a 



nels extend 



throughout closed cone, but an open cone. The top of each cone 



the tree, ^ ^ 



pXome ^ crater. The pith passes through this 



sSdiiigto crater, and the top bud is seated on this pith. The 

 ramifica- pith of cacli sldc-bud also joins the pith of the twig 



tions of the 



roots and to wliicli it is attached, as the pith of each branch 



branches of ^ 



treVwWch which emauatcs from the stem joins the pith of the 

 aii?e."^'^'^ stem. This may be seen to be so in Plate I. ; and 

 also, if you divide an end-bud of a horse-chestnut 

 branch, or if you divide the branch at any of the joints, 

 where one year's growth ends, and the next begins. 

 The channel of the pith may be seen to be continuous 

 through the head of each annual cone ; of the same 

 size as the upper part of the older growth, and con- 

 siderably smaller than the lower part of the newer 

 growth. The pith, in fact, tapers upwards precisely as 

 the shoot does ; and the pith of the new year's shoot, 

 notwithstanding its communication with the taper top 



