16 BOTANICAL GAZETTE [JANUARY 
diameter of the structure in its original form. The general color 
is that of brown coal. The surface shows occasional areas of 
thin coaly matter much broken up into small angular fragments, 
but it is chiefly characterized by a somewhat finely striated 
appearance due to removal of the cortical layer, with consequent 
exposure of the underlying strands of sclerenchyma. 
The transverse section of the more perfectly preserved 
specimen shows an outer zone 1.5™™" thick, which is continuous 
on allsides. Central to this and thus forming the axis of the 
original structure, is a distinctly darker and somewhat more 
porous mass, containing, here and there, small irregularly 
rounded masses of pyrite. Upon subsequent microscopical 
examination, these zonal appearances were found to be due to 
well defined differen es of structure. 
The microscopical details present many features of interest 
and, although the general effects of decay and compression have 
been to completely destroy the general relations of parts, and in 
many cases, also, to destroy structural details, these last have been 
preserved, in some instances, in a remarkably perfect manner. 
THE CENTRAL Axis.—The entire central portion of the stem 
presents a complete absence of structural detail. The whole 
central area is occupied by a mass of dark colored material so 
disposed as to indicate its probable derivation from thin walled 
tissue, but much altered by decay and the subsequent effects 
of extreme compression. Here and there, dark colored masses 
appear, possibly the residue of the mucilage originally present. 
Throughout this region large rounded openings appear, and 
while some of these undoubtedly represent the displacement of 
pyrite, many, and probably all, represent the former locations of 
vascular bundles. In the dark color and structural character of 
this area, we find ample reason for its evident separation from 
the cortical zone, as ascertained upon microscopical examination. 
Outwardly, this area is limited by a somewhat well defined but 
narrow and irregular darker line, which is obviously composed 
of much compressed thin walled cells, but which, nevertheless, _ 
seems to = a eaaconinianes definite prom? lige. between 1 
Bon ge ge ONS ek aaa ae ae Be 
ant eT 
ee ise Sera ok 
