ES 
= 
a= 
1884,] 481 [Branner. 
in exactly the opposite direction to that given them by the drooping of 
the frond.* 
Gaudichaud maintained that the fibro-vescular bundles of the palm- 
trunk ran down into the roots. My own observations agree with those of 
Von Mohl, that there is no such direct connection between the bundles of 
the stem and those of the roots. Anyone acquainted with the habits of 
such a palm as /riartea exorrhiza could never have conceived a theory so 
out of keeping with the facts of the case. This palm puts out new roots 
continually, as do almost all palms, and always above the older ones. If 
the bundles of the trunk ran directly into the roots, the same roots would 
have to serve the tree through its whole lifetime, for the number of bun- 
dles in the trunk does not increase. To be sure, Gaudichaud maintained 
that the bundles descended from the fronds to the roots, and granting his 
premises there might have appeared to be some reason in this conclusion. 
But the supposition that the bundles ran downwards necessitates, as a 
consequence, a base much larger than the upper part of the trunk, as well 
as a continually increasing one, or else very small bundles at the base. 
None of these things are found to be so, but it is found that the bundles of 
the trunk do not run into the roots. 
Von Mohl considers the spines on the aérial roots of Driartea exorrhiea 
to be aborted rootlets, and directly connected with the fibro-vascular 
bundles of the roots. I also found them to be aborted rootlets, but they 
are as independent of direct connection with the bundles of the roots 
proper, as are the roots themselves of the bundles of the trunk. 
In conclusion I find: (1) that all fronds and spadices originate at the 
centre of the phylophore ; (2) that the fibro-vascular bundle division con- 
tinues to grow until its frond reaches maturity ; (8) that the growth of a 
palm trunk continues as long as the bundle divisions of the part are in 
active connection with living fronds, and no longer; and (4) that the 
growth of palms is therefore an internal growth, and the term endogen is 
not a misnomer as far as palrns are concerned. 
From another point of view I find, that the outward appearance of a 
palm, the form of its trunk, the plume-like drooping of its fronds, the 
motion given them by the wind, the breaking and twirling of its leaflets, 
and its general picturesque beauty are only the outward manifestations 
of the laws of its internal growth and structure. 
* Another interesting point in regard to the bundles in the fronds is the direc- 
tion in which they face. (For want of a better definition I have spoken of the 
side of the bundle connecting with the parenchymous system as the face.) T 
have not made a sufficient number of observations to enable me to speak au- 
thoritatively upon the subject, but in the few instances in which TI observed 
this facing of the bundles, they tended to face the centre in the petiole and 
midrib just as they did in the trunk, In order to assume this position the 
bundles in the lower side of a frond retain the position they have on leaving 
the trunk, while the upper ones twist one way or another in what seems an en- 
deavor to turn over and face the centre of the new stem—that is, of the petiole. 
PROC. AMER. PHILOS. 800. xxi. 115, 81. PRINTED MAY 29, 1884. 
