192 THE LATE DR. NEWELL ARBER: CRITICAL STUDIES 
decorticated condition. In the case of fig. 2, the leaf bases are smooth and 
much longer than broad. There is no definite leaf scar, but apparently a 
slight, very impersistent keel occurs in the upper part of the base. Fig. 4 
may be neglected entirely. It is highly suspicious on the score of aceuracy 
and is probably entirely misleading. 
Turning now to the types of the same authors Z. selayinoides (pl. 16. 
lig. 3; pl. 17. fig. 1) one finds simply two leafy stems, which, in those parts 
which are leafless, are more or less decorticated. The identity of L. sela- 
ginoides, Sternb. with L. Iycopodioides, Sternb., is, I believe, now gene rally 
admitted (15. p. 137 ; 16. p. 795). Ido not propose to discuss this matter 
further, since I regard it as proved that the two forms have been found in 
organie continuity and are therefore one and the same plant. The specimens 
figured by Sternberg under the name L. dichotomum a year earlier than the 
above types, have long been a puzzle to palæobotanists and will probably 
continue to be a stumbling-block. I do not propose to enter in detail into 
previous opinion as to their nature, except to add that most authorities have 
regarded them as distinct from both L. lycopodioides and L. ophiurus and as 
the type of a distinct species (L. dichotomum) which was first fully figured 
by Zeiller. My view is that the specimens figured by Sternberg, 1820, on 
plates 1 & 2 (except the lower left-hand figure on plate 2), are all, so far as one 
can judge from the leaf bases, simply typical L. lycopodioides, I regard them 
as distinet from the specimen figured under the same species by Sternberg 
in 1838 on plate 68. fig. 1 of the 7th part of his * Versuch.’ This plant 
I propose to re-name L. loricatum (see p. 201). 
Omitting Bischoff’s figure, which is simply a copy of one of Sternberg's, 
we next reach Lindley and Hutton's examples figured in the second volume 
of their ‘Fossil Flora’ While Lam in some doubt about their plate 113, since 
the leaf bases are either decorlicated or imperfectly represented, the plate 
118 of the same authors appears to me to represent typical leaf bases of 
L. lycopodioides. Of Zeiller's figures, one example figured in both places is 
decorticated. The figs. 3, 34 of the Valenciennes Flora are, however, very 
important, as the earliest clear example of the characters of the leaf bases of 
this species. Tt is obvious that this great authority held the same view 
which I hold as to the true nature of this species. In place of a leaf scar one 
finds a erescentie, somewhat triangular slit, while the lower part of the keel 
of the leaf base has small transverse notches. One of the figures of this 
plant whieh I published in 1903 from the Lancashire coalfield may be 
slightly decorticated, while the other from the Cumberland field, which 
appeared in the same year and was re-figured on a larger scale in 1909, is 
typical. The transverse ridges on the keel are here prominent. 
With regard to Zalessky’s figure (1904) it is a little difficult without 
seeing the specimen to feel sure as to the species which it represents, though 
the leaf scar appears to me to agree with Z. lycopodioides. The keel, 
