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VII. On the Organization of the Fossil Plants of the Coal-measures. — Part VIII. 
Ferns (continued) and Gymnospermous Stems and Seeds. By W. C. Williamson, 
F.R.S., Professor of Natural History in the Owens College , Manchester. 
Received May 2,— Read May 18, 1876. 
[Plates 5-16.] 
In one of his valuable Memoirs on the Fossil Plants of the Carboniferous deposits of 
France* M. Renault has described the stems of two fossil Ferns, to both of which 
examples characteristic petioles are attached. In these stems the chief vascular or 
pseudo-vascular elements are not scattered over the transverse section of the stem in 
detached bundles, as is usual amongst living Ferns, but they are gathered together so as 
to form an axial cylinder, enclosing an irregular, central, radiating medulla composed of 
parenchymatous tissue. In the sixth of this series of memoirs I figured (plate 58. 
fig. 51) a transverse section of a similar vascular axis, but without either petioles or 
even any investing cortical layer attached to it. In one of M. Renault’s examples the 
petioles associated with the stem were identical with those to which Corda gave the 
name of Zygopteris. In the second species, to which M. Renault assigned Corua’s 
generic name of Anachoropteris, the transverse section of the petiolar vascular bundle 
resembles that of Osmunda and Todea , as M. Renault has correctly indicated [loc. cit. 
p. 176). He also points out the difference existing between the closed vascular cylinders 
of the stems of these two Ferns and the corresponding bundles of most living types, but 
thinks that something similar to them may be found amongst the Ophioglossums. 
I am indebted to my indefatigable auxiliary, Mr. J. Butterworth, for an interesting 
stem of the same type which he obtained from the rich reservoir of fossil plants near 
Oldham. The specimen was about \ \ inch in length, whilst its somewhat oval, trans- 
verse section had a maximum diameter of about an inch. The external surface was 
strongly marked by an irregular series of transverse ridges and furrows, represented in 
fig. 1, and which may some day contribute to the identification of the fronds with which 
this stem should be associated. There are about twenty-four of these ridges, with 
corresponding intermediate furrows, to each vertical inch of the stem. On making a 
transverse section of the specimen I found a central vascular cylinder closely resembling 
that seen inM. Renault’s specimen of Zygopteris Brongniarti (l. c. pi. 3. fig. l,a), along 
with two or three secondary ones, of varying dimensions, dispersed over the area of the 
* “ Etude de quelques ve'getaux silicifies des environs d’Autun,” par M. Renault, Annales des Sciences 
Naturelles, 5 e serie, Bot., t. xii. (Cahier no. 3). 
MDCCCLXXVII. 
2 H 
