NOTES. 
THE STRUCTURE OF LEPIDODENDRON OBOVATUM, STERNB.— It 
rarely happens that the palaeobotanist has the opportunity of investigating the 
anatomical structure of a specimen which at the same time exhibits external 
characters allowing of its specific determination. In the present preliminary note 
I propose to place on record a case of this kind which has recently come under my 
observation. 
On December 15, 1904, I received from Mr. J. Parker, of Earby, near Colne, 
Lancashire, among other specimens from the Lower Coal-measures at Towneley, 
the petrified stem of a Lepidodendron, from which the matrix had split away in such 
a manner as to expose a part of the external surface of the plant* The exposed 
surface is completely clothed by the leaf-bases, of which about twenty are visible ; 
they are not flattened, as is usually the case in the ordinary casts, but stand out in 
strong relief. The scar from which the leaf had fallen is plainly seen at the top of 
each cushion, and the cushion itself has a well-marked median rib. On either side 
of the rib the lateral prints can in some cases be clearly seen ; the markings on the 
scar itself are somewhat obscure. The detached portion of the matrix, giving the 
mould of the surface, shows the corresponding features clearly. The general outline 
of the leaf-cushions is rhomboidal with rounded angles ; the slope of the lateral surfaces 
towards the rib, together with that of the scar above, gives the whole somewhat the 
form of a three-sided pyramid, modified, however, by the fact that the rib itself 
has a concave curvature. 
The plant was evidently capable of specific determination, and with this view 
I submitted the specimen to the highest systematic authority in this country, 
Mr. R. Kidston, F.R.S., who kindly examined it, and states in a letter dated March 17, 
1905, ‘The specimen showing structure is without doubt Lepidodendron obovatum! 
The species having thus been satisfactorily identified, I sent the block to 
Dr. Krantz, of Bonn, to have sections cut, taking care that the part showing the 
superficial characters should be preserved uninjured. 
In addition to the branch (A) of which the surface was exposed, the block 
contained another specimen, evidently of the same nature, but immersed in the 
matrix. Sections were prepared from both branches, which proved to be united 
below, forming part of the same dichotomizing stem. 
The branch A showing the surface measures about 50 x 30 mm., the other 
is somewhat larger, having a diameter of about 65 x 25 mm. in its present condition, 
the leaf-bases being included in each case. The preservation is very fairly good. 
The stele has a medulla, enclosed within the broad ring of primary centripetal wood, 
which does not show any specially well-marked corona. Surrounding the primary 
[Annals of Botany, Vol. XX. No. LXXIX. July, 1906.] 
