O THE PALM -STEM. 



direction in the stem ; but it must not be hence inferred that the vascular 

 bundle of Palms is perfected in this direction in its formation ; and in the 

 following pages I shall, according as it may be more conveniently stated, 

 follow the vascular bundle, in the anatomical description, sometimes from 

 above downward, and sometimes in the opposite direction. 



The course of the vascular bundle is the same in all 

 Palms, and the only distinctions which present themselves 

 are a difference of aspect at different points of the course 

 of the vascular bundle in different species. 



In those species, for instance, which, like Kunthia 

 montana and Manritia aculeata, possess firm woody vas- 

 cular bundles only at the periphery of the stem, with a 

 centre composed of soft, herbaceous substance, we find 

 that all the bundles are thin, soft, and herbaceous from 

 the point where they enter the leaf, downward to the 

 centre of the stem, and from here outwards to the point 

 where they approach the outer hard, woody layer, and that 

 as they proceed downward in their course in that layer, 

 they gradually become denser, and of a firm ligneous con- 

 sistence. When the vascular bundles have reached the 

 external part of this layer, and become situated beneath 

 the rind, their thickness is diminished, but not their 

 firmness and hardness ; the latter peculiarity, however, is 

 less remarkable, on account of their smaller diameter. 

 They run in this manner, in the form of slender fibres, 

 between the firm, woody layer and the rind, to the base 

 of the stem, or terminate, after a course of variable length, 

 in other vascular bundles, becoming blended with them. 

 As all the vascular bundles have a similar course, and the 

 portion running in the middle of the stem is soft and 

 herbaceous in all, the medulla-like softness of the centre 

 of the stems is easily explained. It is also clear that the 

 hardness of the outer layer of the stem results from the 

 thickness and solidity acquired by the collective vascular 

 bundles during tkeir course through this outer layer ; 

 further, that the liber-like fibrous layer under the rind is 

 formed by the lower extremities of the vascular bundles, 

 and is not to be compared with the liber of Dicotyledons. 



