426 CONSERVATIVE ORGANS. [LECT. VIII. 



the side of the stem where no leaf is given off; 

 but b. when it arrives at the base of 

 the leaf c. divides, and one part d. 

 enters the leaf, while the other, curv- 

 ing inwards, continues its course 

 along the stem : it then gives off a 

 bundle a little higher up, which ana- 

 stomozing with a bundle from d. forms 

 part of the fasciculi for supplying the new shoot, 

 originating in the axilla of the leaf. The sep- 

 tum is not a thin plate or diaphragm traversing 

 the hollow of the stem ; but a mass of cellular 

 substance, which, in the example before us, oc- 

 cupies the space from e. tof. and is condensed in 

 the centre where it appears white and opaque. In 

 a thin longitudinal slice examined under the mi- 

 croscope, we find that the cellular matter forming 

 the septum is the same as that of the other parts, 

 except where it is condensed in the centre (Plate 

 9, fig. 9, h. *), at which place the cells assume a 

 .horizontal position, as if the cellular texture in the 

 parts above and below terminated at that spot, 



* In this figure (which represents a longitudinal section, 

 passing through the smaller vascular fasciculus marked e. fig. 8), 

 a. is the cellular matter of the cortex ; b. a bundle of proper 

 vessels separated by a slip of cellular substance from the sap 

 vessels e. which are simple spirals, surrounded by a few oblong 

 cells d.f. : the cells g. which supply the place of the pith, are 

 condensed at h. forming the real septum in the hollow parti- 

 tioned stem. 



