APPENDIX.

65

direction of the fibres, must be thrown aside. There arestill further reasons against Meneghini’s asserted lateralmotion of the leaves. If the oblique direction of thefibres were caused by such a motion, it is evident that allthe fibres ought to run in the same direction (right orleft), since this movement of the leaves must have thesame effect as a twisting of the stem. Therefore, if aPalm-stem be split longitudinally, the split surface ought tofollow that spiral in which the fibres run in the stem, andno fibres should be torn by such a splitting, as they wouldall be homodromously curved in their course downwardsfrom the centre of the stem. I investigated this condi-tion in a stem of the Brazilian Palm, which has latelybeen imported for manufacturing purposes, in lengths ofabout seven inches. The split surfaces of this stem neverrun in an oblique direction, but always parallel with theaxis, and a considerable resistance is offered in the processof splitting, since, in the split, not only are fibres runningparallel separated, but a very great number of the fibresof the stem must be torn across, because one portion ofthe fibres runs obliquely through the stem from right toleft, and another in the opposite direction. Thus, inreference to this oblique direction of the fibres, exactlythe same condition occurs in the Palms as in Bracmia,Yucca, and still more evidently in Xanthorrhcea, in whichthe fibres running right and left lie in alternating layerssurrounding the stem, exhibiting in the cross section someresemblance to the annual rings of a Dicotyledonous stem.

It is sufficiently shown by the preceding observations,that the explanation given by Meneghini of the obliquecourse of the vascular bundles cannot be correct, eitherin Braccena, or in the stems which have amplexicaulleaves; we must seek the reason of it, not in mechanicalcauses, but in the organic activity of the plant.

In reference to the vascular bundles of the root,Meneghini observed that in a young Chamcerops theypassed directly into the vascular bundles of the leaves;but that in the roots breaking through higher up on an