198 



PT. IV. 



annually, each year tlie stem incloses a larger circum- 

 ference ; and that part of the branch which is inclosed 

 is in the form of a cone, its base at the bark, and 

 diminishing inwardly towards the pith. The outer part 

 of the branch is in the form of a cone, its base at the 

 bark, diminishing outwardly. But no such internal cone 

 exists except in appearance, that is, in colour^ when a 

 branch has died while the tree was alive : and doubt- 

 less De Candolle has been deceived by the appearance 

 of knots formed by branches which died and dried 

 before the tree was cut. When a branch dies while 

 the tree is alive, it will indeed dry in and change colour 

 in the form of a cone ; because, as the continuation in 

 the stem of its annual growths is not peculiar to the 

 branch, but common to tlie whole tree, they do not 

 dry in and change colour like the dead branch, but 

 remain moist conduits for the upward sap to the head 

 of the tree. But as long as the branch is alive, the 

 medullary rays and longitudinal woody fibres of the 

 new annual growth of it are prolonged, and run verti- 

 cally down that part of the stem of the tree which is 

 below the branch ; so that it is only the grain of the 

 centre part of the branch, that is, its first year's 

 growth, which runs across the grain to the centre of 

 the tree. It then in general joins the second year's 

 growth of that part of the stem wliich is below it, and 

 riuis down the stem of the tree to the roots. The 

 grain of every other year's growth of the branch 

 annually turns down the stem of the tree, short of the 



