om of the higher Spore-plants, the Cryptogamia possessing a
vascular system, was more prominent in early geological periods than at
present. It is true that the dominance of the Pteridophyta in Palaeozoic
times has been much exaggerated owing to the assumption that everything
which looked like a Fern really was a Fern. But, allowing for the fact,
now established, that most of the Palaeozoic fern-like plants were
already Spermophyta, there remains a vast mass of Cryptogamic forms
of that period, and the familiar statement that they formed the main
constituent of the Coal-forests still holds good. The three
classes, Ferns (Filicales), Horsetails (Equisetales) and Club-mosses
(Lycopodiales), under which we now group the Vascular Cryptogams, all
extend back in geological history as far as we have any record of the
flora of the land; in the Palaeozoic, however, a fourth class, the
Sphenophyllales, was present.

As regards the early history of the Ferns, which are of special interest
from their relation to the Seed-plants, it is impossible to speak quite
positively, owing to the difficulty of discriminating between true
fossil Ferns and the Pteridosperms which so closely simulated them.
The difficulty especially affects the question of the position of
Marattiaceous Ferns in the Palaeozoic Floras. This family, now so
restricted, was until recently believed to have been one of the
most important groups of Palaeozoic plants, especially during later
Carboniferous and Permian times. Evidence both from anatomy and from
sporangial characters appeared to establish this conclusion. Of late,
however, doubts have arisen, owing to the discovery that some
supposed members of the Marattiaceae bore seeds, and that a form of
fructification previously referred to that family (Crossotheca) was
really the pollen-bearing apparatus of a Pteridosperm (Lyginodendron).
The question presents much difficulty; though it seems certain that our
ideas of the extent of the family in Palaeozoic times will have to be
restricted, there is still a decided balance of evidence in favour
of the view that a considerable body of Marattiaceous Ferns actually
existed. The plants in question were of large size (often arborescent)
and highly organised--they represent, in fact, one of the highest
developments of the Fern-stock, rather than a primitive type of the
class.

There was, however, in the Palaeozoic period, a considerable group of
comparatively simple Ferns (