APPENDIX. 61 



the size which the stem must acquire, since this expan- 

 sion of the lower intern odes would again be followed by 

 an expansion of their cicatrices in breadth, which would 

 again necessitate an increased expansion of the part of 

 the stem lying between the borders of the leaves (for this 

 part should equal J of the cicatrix) ; and in consequence 

 of this, the upper leaves would be again expanded in 

 breadth, which expansion would react again upon the 

 lower internode, and so on. It is easy to see that this 

 cannot be the proceeding which nature follows in the 

 growth of these stems, since it would lead to an immense 

 increase of thickness, even if it were restricted to a con- 

 dition where the margins of the leaves were separated 

 about i of the breadth of the leaf at the complete develop- 

 ment of the latter; and that in Draccena, where the 

 separation of the margins of the leaves would equal 

 double the breadth of the latter, the increase of the dia- 

 meter of the stem must occur in a far more excessive 

 proportion. Since, therefore, on the one hand, these 

 conclusions, which are necessary deductions from the pro- 

 cesses asserted by Meneghini to occur, would lead to 

 impossibility, and, on the other hand, both direct obser- 

 vation of the cicatrices and the anatomical examination 

 of the stem testify most clearly against this notion of an 

 unequal growth of the leaf-scars and the circumference of 

 the stem, the divergence of the fibres from the perpen- 

 dicular line cannot be caused by the mechanical process 

 supposed by Meneghini. 



Even if this oblique direction of the fibres were a con- 

 sequence of the unequal growth of the leaf-scar and the 

 circumference of the stem in Dracana, Aletris, &c., this 

 derivation of it would not be applicable to the Palm-stem, 

 since this always has its leaves and leaf-scars surrounding 

 the stem. Meneghini did not overlook this circumstance ; 

 but he imagined he had discovered a second mechanical 

 cause, which produced an oblique position of the fibres 

 also in the stems with completely amplexicaul leaves, and 

 which consisted in a movement of the leaves to one side. 



