64

THE PALM-STEM:

shorter, looking at its absolute size, the nearer it is to theinner end, but the angular divergence of the leaves willbe the same. If this be the case, and I believe that allinvestigations hitherto made testify that such is the con-dition, it is evident that the movement of every leaf takesplace in the radial direction, and is simply a consequenceof the elongation and expansion of the axis ; that themotion of any leaf in a spiral direction is only apparent,and results from the fact that the spiral line has no defi-nite place upon the upper surface of the bud, but itspoint of origin continually advances in the direction inwhich the leaf-spiral runs, into the circle which is formedby the connexion of the cylindrical surface of the stemwith the depressed surface of the bud. If such be thecondition, the leaves must appear to traverse the outerturns of the spiral more rapidly than the inner, since thesame angles of divergence correspond to larger segmentsof turns in the outer parts of the spiral, while, accordingto Meneghini’s theory, the contrary occurs : the motion ofthe leaves diminishes in regard to the angle of divergencein the outer turns of the spiral, but in regard to the spacespassed through remains the same, and thus must appearto become slower. Since, although I had investigatedthe terminal buds of some large Monocotyledonous plantsin reference to this point, and had found no notabledeviation with regard to the divergence of their leaves,my judgment on this matter could not be nearly so va-luable as that of my honoured friend, Professor AlexanderBraun, I wrote to ask him whether he had ever met withcases of such a deviation in the divergence in the terminalbud as is required by Meneghini’s theory, and obtainedthe answer, that he is indeed of opinion that it is verydifficult to settle this point with certainty by direct obser-vation, but from his own researches, he believes the diver-gence in the terminal bud to be the same as in the stem.From this important confirmation of my views, it appearsto me that the entire doctrine of an actual spiral motionof the leaves, and the deduction from it of the oblique