584 
MR. E. W. BINNEY ON SOME LOWER-COAL-SEAM EOSSIL PLANTS. 
tissue composing the central axis, and having the inner portions of the wedge-shaped 
bundles forming the internal radiating cylinder of a convex shape as they approach the 
central axis, somewhat like those represented by Brongniart in his SigiUaria elegans , 
and still more resembling those described by Corda in Diploxylon cycadoideum* ; but my 
specimen shows within those convex bundles a broad zone of scalariform tissue arranged 
without order and marked with transverse striae. 
It has been assumed, both by Corda and Brongniart, that Diploxylon had a pith 
composed of cellular tissue, surrounded by a medullary sheath of hexagonal vessels 
arranged without order, barred on all their sides with transverse striae. My specimen is 
evidently more complete in structure than those of the last-named authors, or even that 
which Witham himself described ; but although it shows the so-called medullary sheath 
in a very perfect state, there is nothing to indicate the former existence of a pith of cel- 
lular tissue. All the specimens examined by Witham, Corda, and Brongmart appear 
to have had their central axes removed altogether and replaced by mineral matter, 
or else only showing slight traces of their structure ; and these authors appear to have 
inferred the former existence of a pith of cellular tissue, rather than to have had any 
direct evidence of it in the specimens of Anabathra , Diploxylon, and SigiUaria respect- 
ively figured by them. Every collector of coal-plants is well aware of the blank space 
so generally left in the above fossil plants as well as in the roots Stigmariae. It is quite 
true that a little disarrangement of the scalariform vessels ( a ') in the specimen is seen ; 
but the part which remains undisturbed shows that the whole of the central axis was 
formerly composed of hexagonal vessels arranged without order, having all their sides 
marked with transverse striae and not of cellular tissue. This view is confirmed by 
another and more perfect specimen of Anabathra in my cabinet, and enables me to 
speak with positive certainty, and to show that these three plants had a similar struc- 
ture in the central axes to the specimens of SigiUaria vascularis described by me in my 
paper published in the Quarterly Journal of the Geological Society. 
My specimen clearly proves the existence of medullary rays or bundles traversing 
the internal woody cylinder, which originate on the outside of the central axis ; and it 
appears to me pretty certain that Corda’s specimen of Diploxylon cycadoideum , if tan- 
gential sections had been made and carefully examined, would have done the same. 
The exterior of the specimen is not in a very complete state of preservation, but it 
seems to have been covered by irregular ribs and furrows, with slight indications of 
remains of the cicatrices of leaf-scars. Its marked character, as previously alluded to, 
is the great space occupied by the central axis. This is of much larger size than in 
either the SigiUaria vascularis or the specimens intended to be next described. 
The lunette-shaped ends of the wedge-like bundles of the inner woody cylinder bear 
some resemblance to the form of the same parts of the SigiUaria elegans of Brongniart, 
but much more to those of Corda’s Diploxylon cycadoideum , with which it appears to 
be identical. 
* See M. Beongniakt’s paper on SigiUaria, previously quoted. 
