OF COAL-MEASURE PLANT-IMPRESSIONS, 173 
many of which have been collected by myself, I have come to the conclusion 
that the cones fall into three groups or subgenera, which may be conveniently 
described as follows :— 
Kulepidostrobus. Cones in which the sporophylls are comparatively leaf- 
like, with no great dissimilarity in size or shape between the pedicel 
and the lamina, e. g. L. variabilis, Lindl. & Hutt. 
Ortholepidostrobus, Cones in which the distal portion of the sperophylls 
or laminæ are greatly expanded and developed as compared with the 
proximal regions or pedicels, e. g. L. majus, Brongn. 
Sublepidostrobus. Cones in which the proximal portions of the sporophylls 
are much better developed than the distal regions or laminæ, e.g. 
L. Jacksoni, Arb. 
The Æulepidostrobi are the most difficult group from a taxonomie stand- 
point. [am inclined to recognise only one species in Britain, L. variabilis, 
Lindl. & Hutt., where other authors distinguish several. There are, it is 
true, enormous differences in both size and shape between cones of this 
species and the strobili known as L. Geinitzi, Schimp., and L. ornatus, 
Brongn , but I can find no real macroscopic differences in the form of the 
sporophylls which can be clearly made out in impressions. No doubt such 
differences do exist, and, had we to deal with nothing but petrifieations of 
these cones, we might diseriminate further species founded on small 
characters, But the fact remains that these cones are so stereotyped that 
viewed merely as impressions it is not possible to diseriminate between them 
except in respect of size, always a dangerous index in taxonomy. It is thus 
better to recognise the limitations of our powers in this direction by referring 
these fossils to one stereotyped species, than to attempt to specify a number 
of types which cannot be clearly distinguished from one another. The case 
of L. variabilis is exactly “on all fours” with that of Stigmaria ficoides. 
The Ortholepidostrobi * have at least one feature in which they stand apart 
from other members of the genus, i.e. the caducous nature of the sporoph ylls. 
In the other two groups the sporophylls are remarkably persistent, and it is 
rare to find among them a Zepidostrobus axis which is not fully clothed with 
sporophylls. In the case of the Ortholepidostrobi, the sporophylls are so 
easily detached from the axis that until a few years ago they were only 
known in the isolated state. They were then generally referred to the genus 
Lepidophyllum, e.g. Lepidophyllum lanceolatum, Lind]. & Hutt. The present 
paper contains the first figured examples of more than one type of these 
sporophylls still attached to the axis of the cone. In regard to all the 
British types here described, it may be now regarded as proved that they 
are not foliar leaves, as was at one time thought, but the sporophylls of a 
cone, and thus they are best referred to the genus Lepidostrobus. The genus 
* The term “ortho” in the sense of “erect” recalls the very erect position of the laminas 
of the sporophylls of these cones. 
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