or THE FOSSIL PLANTS OE THE COAL-MEASUEES. 
21 
Besides the remarkable branches which I have just described, I find clear evidence of 
the existence of another, and apparently very different, set of divergent vascular bundles, 
and which pass outwards through the large cellular radii (h) which separate the primary 
woody wedges. But I find it much more difficult to obtain a clear conception of the nature, 
origin, and distribution of these bundles than of those previously noticed. In fig. 30 there 
is represented a condition of which I have seen several examples. In the parenchyma 
(h) separating the two primary vascular wedges d and d' there is an obvious derange- 
ment of the usual condition of the cells of that parenchyma at y. The latter display an 
obvious disposition to be elongated radially, bending outwards to accompany a small 
bundle of vessels seen at y, which is here cut across by the tangential section somewhat 
obliquely. In fig. 35 we have a similar but more perfectly tangential section of one of 
the same cellular radii ( h ), with portions of two primary vascular wedges at d, d'. At y 
we again find a cluster of small vessels passing outwards. At e, e' we have some mean- 
dering vessels detached from direct connexion with each of the two primary bundles 
( d , d'), but which obviously contribute to swell the diameter of the intersected bundle, y. 
At e" we find a few vessels, separated from those of the primary bundle ( d ') by a few mural 
cells of a medullary ray, and which appear to be descending to reach the bundle y, 
towards which their lower extremities bend away from the primary wedge, d! . In fig. 36 
we again find a similar bundle ( y ) passing through the coarse parenchyma of the outer 
bark, apparently on its way to escape through the epiderm, Jc. Though I have seen in 
my sections several other similar indications of these bundles, none of my specimens 
throw any clear light upon them. That they are distinct from the branches previously 
described appears very possible ; but what is their ultimate purpose I have not yet suc- 
ceeded in ascertaining. If the vessels e and e" in fig. 35 really go to the bundle y , as 
they appear to do, there can be no doubt but that they are respectively derived from the 
two primary vascular wedges, d and d 1 . But I cannot yet determine satisfactorily 
whether the bundle y consists wholly of vessels, or of vessels mixed with cells derived 
from the inner cortical layer through which they emerge. There are indications that 
some of the cells of the latter are elongated radially to form a sort of sheath to the 
vessels. All these points are at present but obscurely indicated by my specimens ; but 
the general features of these bundles differ so widely from those of the true branches 
represented by figs. 32, 33, & 34 as to leave little doubt that they have had a distinct 
nature, having probably been destined to supply either rootlets or leaves with vessels. 
Unfortunately my specimens of this very rare plant have hitherto been too few in number 
to enable me to obtain such a good radial section as might throw light upon these 
diverticula of the central vascular axis. At the same time it may be possible that these 
bundles pass outwards to become the central bundles of branches corresponding to 
figs. 24 & 25. 
The question of the nature and probable affinities of this plant remains to be exa- 
mined ; and here, again, we have unfortunately to deal with much that is obscure. In 
the vascular character of its primary central axis (figs. 23-24, c) we are reminded of 
