72 THE PALM-STEM : 



thinks they may stand in connexion with the leaves. 

 When Mirbel then proceeds, that my statements as to 

 the relations of the vascular bundles of the roots to those 

 of the stems are not contradicted by this, but only carried 

 out to their real extent, I am far from calling in question 

 the accuracy of the observations made by Mirbel on the 

 Date-palm, but must defend myself from the construction 

 which must almost necessarily be attached to Mirbel's 

 expression, that, namely, my observations, and the con- 

 clusions to be drawn from them, had been essentially 

 modified, and that a more direct transition of one part 

 of the vascular bundle of the root into that of the stem 

 occurs universally. The essential point which I established 

 by my observations on the roots of Monocotyledons, is 

 the fact that the root is an independent structure, possess- 

 ing its own special system of vascular bundles, that these 

 are not gradually elongated outwards, towards the point 

 of the root, but also increase in length in the posterior 

 extremity, lying in the stem, penetrate into the stem from 

 the cellular mass which constitutes the basis of the root- 

 bud, form an interlacement with the vascular bundles 

 of the stem, and become attached to them. 



All doubt as to this independence is removed by the 

 investigation of the root-bud, for its vascular bundles are 

 originally entirely separate from those of the stem ; but it 

 is also perceptible, subsequently, that at least the greater 

 proportion of them are not directly continuous with the 

 vascular bundles of the stem, but, with an alteration of 

 their structure, an interlacement is formed, in which they 

 apply themselves to the sides of the vascular bundles of 

 the stem, without actually passing over into them. The 

 bundles of the branches of the root stand in the same re- 

 lation to those of the root as the latter do to those of the 

 stem. On account of the smaller number of vascular bun- 

 dles of the root-branch and the root, and the very different 

 diameter of the vessels of these two organs, it may be ob- 

 served, with the greatest certainty, that an immediate 

 transition of either set of vascular bundles into the other 



