OF THE FOSSIL PLANTS OF THE COAL-MEASUKES. 
497 
observed that those of one node are intermediate, or alternating with, those of the con- 
tiguous one. 
A question is at once suggested by these specimens. What are they 1 Are they a 
distinct species of Catamite, or are they merely some specialized portion of well-known 
forms X The plant which Broxgniart figured and described under the name of Calamites 
ramosus exhibits some features in common with them (Iiistoire de Vegetaux Fossiles, 
pis. 17. figs. 5 & 6), as also do some examples of his Calamites arenaceus. But after 
examining a large number of specimens, I have come to the conclusion that they have 
been vertical subterranean rhizomes. One specimen in the Cabinet of Mr. Wilde espe- 
cially confirmed this conclusion. At its lower extremity it exhibits all the appearances 
of fig. 31, but at its upper end, after giving off a strong branch, it is prolonged in the 
form of an ordinary Calamite. A similar specimen in the Cabinet of Mr. Nield does 
the same. That these rhizomes have been vertical is demonstrated by the direction of 
the branch in fig. 33, by the verticillate arrangement of the branches in the variety just 
referred to, and by the two significant specimens. When large branches are met with, 
detached from such parent rhizomes as fig. 31, the base, composed of several internodes, is 
seen to be truncated as shown in Plate XXVII. fig. 36 ; but very frequently the concentric 
shortened internodes are much more numerous than in that example. These internodes 
exhibit, even at the truncated base, the same longitudinal ridges and furrows as occur 
on the free stems, indicating that their woody wedges, to which these lines are due, 
radiate regularly from a central point representing the medulla. Of course such spe- 
cimens as that figured are mere casts of the medullary cavity, and beyond indicating 
the size of the internodes and the arrangement of the innermost margins of the woody 
wedges, they throw no light upon the actual relations of the woody zone of the branch 
to that of the rhizome ; but they do show that the medulla of the branch is only 
connected with that of the central rhizome by an exceedingly small cellular union, 
represented in fig. 36 by the dot forming its central point. 
M. Grand’ Eurt has published (Comptes Bendus, loc. cit.) some interesting statements 
respecting the Calamites of St. Etienne. He found long rhizomes running away from 
a central stem, giving off aerial shoots, and then continuing their subterranean course to 
repeat the process at successive and more distant intervals. But the condensed abstract 
of his memoir published in the Comptes Rendus does not enable me to identify his spe- 
cimens of horizontal growths with those which I have just described, though the latter 
are the only ones I have met with in England which I can regard as rhizomes. Neither 
have I been able to satisfy myself as to the exact relationships between these rhizomes 
and such specimens as that represented in fig. 34, a common type of the subterranean 
base of an aerial stem, and a form which now demands a moment’s consideration. 
The conical bases of Calamites are not uncommon. Sometimes they are very obtuse, 
the internodes diminishing rapidly in size ; at others they are drawn out in a more 
tapering manner. Occasionally they are quite straight, but much more frequently they 
are curved, as if they were lateral shoots from some other structure, which in the curved 
examples has doubtless been the case. The lowermost internodes of many such specimens 
