202 Benson . — Cordaites Felicis , sp. nov ., <2 Cordaitean Leaf 
All the micrographs on PL XXII (except Fig. 11) are taken from 
specimens in a single series from the same boulder. The expense of 
the work has been in part defrayed by a contribution from the Royal 
Society Government Grant Committee. 
General Account of the Leaf. 
As may be seen by reference to the micrographs, the specimens exhibit 
a considerable range of structure, but there seems to be no ground for sup- 
posing that more than one species is represented. In the leaves of some 
recent Conifers, as was shown by Seward and Ford in their monograph 
on the Araucarieae, 1 the leaf bundles may be diploxylic near the apex, but 
show no centripetal xylem at the base. Maslen also points out 2 that the 
absence of centrifugal primary wood in the specimens described by 
Dr. M. C. Stopes 3 may be due to their having come from distal parts 
of the leaf, adding: * Until sections of the lamina of Mesoxylon Sutcliffii 
have been identified, it will be impossible to determine to what extent the 
centrifugal portion of the bundles persists out into the leaves.’ 
In the specimens under consideration the thicker parts of the lamina 
contain bundles with a fair development of centrifugal wood and the 
bundles are frequently shown in the process of division (Figs. 5 and 6). 
In thinner parts of the lamina (i. e. presumably more distal or more 
peripheral), the centrifugal elements become smaller, are relatively few 
in number, and in some cases are absent altogether. 4 
The distribution of the sclerenchyma is different in the thicker from 
that in the thinner parts of the lamina. In the former there is an almost, 
if not quite, continuous hypodermal layer beneath each surface. In the 
thinner parts of the leaf the hypodermal layer is interrupted, but both 
regions of the leaf show supporting plates vertical to the surfaces of the leaf. 
These plates form complete partitions running the length of the leaf 
between the bundles and alternating with them (Fig. 3). 
They appear in transverse section like columns, and are the more 
interesting as they do not occur in any of the forms described by 
Grand’Eury or Renault. They are well represented, on the other hand, 
in the forms described by Felix, e. g. C. Wedekindi, C. loculosus y and 
C. robustus . As in most Cordaitean leaves so far described, the vascular 
bundle is surrounded by a sheath attached to both surfaces by thickening in 
1 Seward and Ford : The Araucarieae, Recent and Extinct. Phil. Trans. Royal Soc., B., 
vol. cxcviii, 1906, p. 370. 
2 Maslen : The Structure of Mesoxylon Sutcliffii (Scott). Annals of Botany, vol. xxv, 1911, 
p. 406. 
3 Stopes: On the Leaf Structure of Cordaites. New Phytologist, vol. ii, 1903. 
4 It seems open to question whether this statement is strictly justifiable, as the inner sheath, 
which appears to represent the centrifugal xylem, is generally present even when the more central 
elements are undifferentiated (vide Figs. 8 and 10). 
