Proceedings of the Linnean Society of London - University Library

54
PKOCEEDINGS OF THE
Vascular Cryptogams," tlie position becomes altered, and the
question is one that should engage the attention of Botanists.
When it is borne in mind that, so far as the geological record
goes, seed-bearing plants (Cordaiteae) are of at least equal age
with true Ferns, the perplexities of the situation become
manifest.
Another question upon which an expression of opinion would
be valuable, is whether the A^hole group of Gymnospernis may be
regarded as having been evolved along the Fern-Cycad line, or
whether, on the other hand, some of them at least may have had
a quite distinct origin.
Palaeobotanical work has shown that in the Lycopod phj-lum
seed-like structures were occasionally produced, and this discovery
no doubt seems to strengthen what has always been a possibility,
viz., that a portion of the Gymnosperms may have had its origin
alouo- this line.
III.
On the Earlier Geological Eecord of the True Ferns.
By E. A. Newell Arbee, M.A., F.L.S., F.G.S.
[Eead 15th March, 1906.]
It is evident that the Palaeozoic Pteridosperms exhibit, both in
their habit and anatomy, marked characters in common with the
true Ferns, and it is therefoi*e regarded as more than probable
that they sprang from a Fern-like stock. Thus the Fern line of
descent must be geologically older than the Pteridosperms. Yet
the recent discoveries as to the nature of the male and female
fructifications of these Fern-like, seed-bearing plants have tended
in part to obliterate, and in part to cast strong suspicion upon,
much that was formerly regarded as undeniable evidence of the
existence of the true Ferns in the Palaeozoic Period,
There is, however, every reason to believe that true Ferns did
exist in Carboniferous and Permian times. The Botryopteridese,
and certain unassigued fronds bearing annulate sporangia were
among the chief representatives. But it is doubtful whetlier the
Palaeozoic Ferns were clearly and generally differentiated into
Eusporangiatae and Leptosporangiatae. In the fossil state we have
naturally no evidence as to the development of the sporangia,
and further, the biseriate or multiseriate annulus of Palaeozoic
sporangia does not agree with that of modern Leptosporangiate
spore-bearing organs. It would thus seem better to regard the
Palaeozoic Ferns as a separate class, from which both the Leptosporangiatae
and Eusporangiatae were eventually derived. The name
Primofilices is suggested to denote this race ; since the preferable
terms, Archaeopterideae and Palieopterideae, are not available. The