30 
Remarks. —As is well known, this species, which in the Southern Hemisphere has 
a very Avide vertical range, is an exceedingly difficult fossil to deal with, on account 
of the stereotyped nature of the frond. Were the fertile fronds known, one would 
expect to fold that the sterile foliage of several different plants has been commonly 
included under the term Cladophlebis australis (Morr.). Yet, in dealing with the sterile 
foliage it appears to be quite impossible at present to recognize more than one type 
by any definite characters, apart from mere size. This type, Cladophlebis australis, 
is just as stereotyped as the coal-measure Stigmaria ficoides Sternb. The pinnules 
may be small or relatively large, narrow in proportion to their length, or compara¬ 
tively broad, falcate or almost straight, pointed or obtuse. The nerves may fork 
twice, as in the type specimen, or only once; or in some pinnules one fork of the primary 
dichotomy of the lateral nerve may remain simple, while the other divides again. There 
is also every type of transition between the forms of lateral nervation above indicated. 
It seems to be quite impossible to recognize species founded simply on such variations. 
Further, as regards size, larger and smaller, longer and shorter pinnules may be 
expected to, and no doubt did, occur in different parts of the same leaf. Thus 
Cladophlebis australis is a very unsatisfactory, though at the same time an important 
and characteristic, fossil. 
Further, C. australis appears to differ only from the British and European type, 
C. denticulata (Brongn.), in the absence of the denticulate margins characteristic of the 
latter species. It may well be doubted whether this character alone is of sufficient 
importance to warrant specific separation, especially as both species occur in the 
Mesophytic floras of the Southern Hemisphere, though the former is there more abundant 
than the latter. Professor Seward(l) has, in fact, regarded C. australis as a mere 
variety of C. denticulata. I am inclined, however, to keep the. two species separate, at 
least provisionally. In cases where variations of any sort are so rare it would seem 
advisable to attribute some importance to a perfectly definite character, such as the 
presence or absence of a denticulate margin. But I am still more impressed by the 
fact that among the southern fossils which I have examined C. australis is everywhere 
by far the dominant type, C. denticulata, although occurring, being very much rarer. 
It therefore does not seem that the two fronds were obviously borne by the same 
plant. I am thus in agreement with the conclusions recently arrived at by Halle(2) 
in regard to the Grahamland fossils. 
The specimens of C. australis previously figured by Hector (see synonymy) are 
for the most part fragments of apical portions of what were probably young fronds. 
They differ only in size from the larger leaves, and it appears to me to be quite 
impossible to separate them from C. australis. If once varieties are freely distinguished, 
then every other frond must be constituted a variety, based on very slight characters, 
chiefly as regards size. 
The Neocomian examples, figured on Plate IV, fig. 1, and Plate XIV, have com¬ 
paratively long and fairly distant pinnules. They appear to me to be, however, 
indistinguishable from C. australis. Professor Seward(3) has figured a specimen from 
the Uitenhage beds of Cape Colony,' under the name Cladophlebis denticulata (Brongn.) 
forma Atherstonei, in which the pinnules are even longer, but more closely set. 
Similarly, from the Cretaceous of Greenland, Heer(4) has figured long-pinnuled forms 
under the names Pteris longipennis Heer and Pteris frigida Heer, which, except in the 
denticulate margin, appear to me to be identical with the specimens from Waikato 
(4) Heer (1882), pp. 25, 28, pi. vi, fig. 56; 
pi. x, figs. 1-13 ; pi. xi; pi. xii, fig. 2 ; 
pi. xiii, figs. 1, 2 ; pi. xvi, figs. 1, 2 ; 
pi. xviii, fig. 106. 
(1) Seward (1904), p. 171. 
(2) Halle (1913 1 ), p. 13. 
(3) Seward (1903), p. 14, pi. vi, figs. 10, 17. 
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