60 



Mr. Gardner on the Origin of the 



able to trace their course with great ease. I found that after 

 entering the stem they made a gentle curve downwards and 

 inwards till they reached nearly the centre of the column ; 

 then, changing their direction, they turned downwards and 

 outwards, with a greater degree of obliquity than before, till 

 they reached within a little of the external surface of the stem, 

 after which they continued to descend in a line parallel with 

 its axis, ultimately becoming so much ramified that I was un- 

 able to trace them. The chord of the arc, or the distance from 

 the place where the fibres entered the stem, to the point where 

 they finished their curve, was 2 \ feet. I was not only able to 

 trace the fibres as above described, but could also trace them 

 from the interior of the stem for a considerable distance up 

 into the substance of the leaf itself. 



Longitudinal sections of the stems and leaves of the cab- 

 bage-palm [Euterpe edulis, Mart.), of a very tall species, called 

 by the Brazilians Patt, and of a small one which they call 

 Oricana, all exhibited precisely the same structure, the length 

 of the curve of the fibres only differing according to the thick- 

 ness of the stems of the different individuals and the distance 

 between the insertion of the leaves. 



The stems of all the species split with difficulty, owing to 

 the great mesh-work of interlaced fibres. 



Having thus shown that the views of Mohl regarding the 

 origin and direction of the woody fibre of the stems of palms 

 are quite in accordance with what I have myself observed, I 

 shall now make a few remarks on the objections, or rather 

 doubts, which Dr. Lindley has expressed concerning them. 

 In the first place, he says, "if Mohl's view of the structure of 

 endogens be correct, they must after a time lose the power of 

 growing in consequence of the whole of the lower part of their 

 stems being choked up by the multitude of descending woody 

 bundles. Is this the case ?" In none of the oldest palm-trees 

 which I have seen cut down did it seem that this would ever 

 be the case, the stem always exhibiting a like thickness of ex- 

 ternal hard, and internal soft portions, from the root to a 

 height of many feet ; and that this ought to be the case, is ob- 

 vious from their structure. As the bundles of woody fibre 

 originate from the leaves, and as they are placed the one above 

 the other on the stem, it follows that the fibres of the upper 

 leaves will not descend so far as those of the lower, and that, 

 consequently, as the stem increases in height so will the den- 

 sity of its sides increase upwards also. In the second place, 

 he says, "the lower part of their bark, too, must be much 

 harder, that is, much more filled with woody bundles than the 

 upper. Is that the fact ?" Every one who has been in the 



