176 THE LATE DR. NEWELL ARBER: CRITICAL STUDIES 
me to be identical with those of L. variabilis. The differences between the 
two species indicated by Zeiller appear to me to be very slight, in some 
cases non-existent—a view which Renault’s figures confirm. I therefore 
conclude that, unless an appeal is to be made to mere size and shape, which 
are notoriously untrustworthy taxonomic guides, there is no real distinction 
between the sporophylls of L. @einitzi and L. variabilis. The two cones may 
be really distinet, but when they are preserved as impressions, there are no 
distinctly visible characters by which they may be distinguished. 
In the case of L. squarrosus, again, according to Kidston the chief differences 
between that species and L. variabilis are the formers “larger size, and the 
much more lax spreading nature of the bracts.” These characters do not 
appeal to me as worthy of specific rank. 
Two very interesting and exceptional impressions of isolated sporophylls 
of this species are figured on Pl. 8. figs. 1,2,&3. Both are from the Middle 
Coal Measures of the Kent Coalfield. 
No. 2242*. Fig. 1, Pl. 8, shows one example, natural size, and the same 
organ is shown enlarged twice in fig. 2. The lamina of the sporophyll 
is seen on the right, and on the left the sporangium. The ligule can be 
clearly seen between the two organs. The structure seen on the left is 
another sporophyll, and not the axis. The sporangium measures 10 mm. 
radially and is about 6 mm. high. 
No. 3201. In another example shown on PI. 8. fig. 3 (natural size), the 
sporophyll is still attached to the axis. The sporangium here measures 
15 mm. across and 4°5 mm. high. 
Cones of the Lepidostrobus variabilis type are known to have been borne 
by several stem-species of Lepidodendron, viz. :—- 
Lepidodendron lycopodioides, Sternb. (including £L. lanceolatum, 
Lesq.). 
L. ophiurus, Brongn. 
? L. loricatum, Arber. 
Types. Lindley and Hutton's in the Hancock Museum, Newcastle-on-Tyne. 
Distribution. Known from all horizons in the Coal Measures and from 
nearly all coalfields. 
LEPIDOSTROBUS RUSSELLIANUS, Binney. 
1871. Lepidostrobus Russellianus, Binney, in Pal. Soc. (Observ. Struct. Foss, Plants, 
Part LI.), p. 51, pl. 9. figs. 1, La, 2, & 2 a. 
1871. Lepidostrobus (?) dubius, Binney, ibid., p. 52, pl. 9. figs. 3 & 3a. 
1871. Lepidostrobus tenuis, Binney, ibid., p. 53. pl. 9. figs. 4 & 4 a. 
1871. Lepidostrobus levidensis, Binney, tbid., p. 54, pl. 10. figs. 1, 1a, & 1b. 
1912. ? Lepidostrobus cf. Russellianus, Vernon, in Quart. Journ, Geol. Soc. vol. lxviii. 
p. G21, pl. 59. fig. 1. 
* The numbers refer to the Carboniferous Plant Collections, Sedgwick Museum, Cambridge. 
