APPENDIX. 65 



direction of the fibres, must be thrown aside. There are 

 still further reasons against Meneghini's asserted lateral 

 motion of the leaves. If the oblique direction of the 

 fibres were caused by such a motion, it is evident that all 

 the fibres ought to run in the same direction (right or 

 left), since this movement of the leaves must have the 

 same effect as a twisting of the stem. Therefore, if a 

 Palm-stem be split longitudinally, the split surface ought to 

 follow that spiral in which the fibres run in the stem, and 

 no fibres should be torn by such a splitting, as they would 

 all be homodromously curved in their course downwards 

 from the centre of the stem. I investigated this condi- 

 tion in a stem of the Brazilian Palm, which has lately 

 been imported for manufacturing purposes, in lengths of 

 about seven inches. The split surfaces of this stem never 

 run in an oblique direction, but always parallel with the 

 axis, and a considerable resistance is offered in the process 

 of splitting, since, in the split, not only are fibres running 

 parallel separated, but a very great number of the fibres 

 of the stem must be torn across, because one portion of 

 the fibres runs obliquely through the stem from right to 

 left, and another in the opposite direction. Thus, in 

 reference to this oblique direction of the fibres, exactly 

 the same condition occurs in the Palms as in Dractena, 

 Yucca, and still more evidently in Xanthorrkoeq, in which 

 the fibres running right and left lie in alternating layers 

 surrounding the stem, exhibiting in the cross section some 

 resemblance to the annual rings of a Dicotyledonous stem. 



It is sufficiently shown by the preceding observations, 

 that the explanation given by Meneghini of the oblique 

 course of the vascular bundles cannot be correct, either 

 in Dracaena, or in the stems which have aniplexicaul 

 leaves ; we must seek the reason of it, not in mechanical 

 causes, but in the organic activity of the plant. 



In reference to the vascular bundles of the root, 

 Meneghini observed that in a young Chamcerops they 

 passed directly into the vascular bundles of the leaves ; 

 but that in the roots breaking through higher up on an 



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