same Cycadean type as those of the Pteridosperms, so that it is not
always possible, as yet, to discriminate between the seeds of the two
groups. These facts indicate that the same fern-like stock which gave
rise to the Cycadophyta and through them, as appears probable, to the
Angiosperms, was also the source of the Cordaiteae, which in their turn
show manifest affinity with some at least of the Coniferae. Unless the
latter are an artificial group, a view which does not commend itself to
the writer, it would appear probable that the Gymnosperms generally,
as well as the Angiosperms, were derived from an ancient race of
Cryptogams, most nearly related to the Ferns. (Some botanists, however,
believe that the Coniferae, or some of them, are probably more nearly
related to the Lycopods. See Seward and Ford, "The Araucarieae, Recent
and Extinct", "Phil. Trans. Royal Soc." Vol. 198 B. 1906.)

It may be mentioned here that the small gymnospermous group Gnetales
(including the extraordinary West African plant Welwitschia) which were
formerly regarded by some authorities as akin to the Equisetales, have
recently been referred, on better grounds, to a common origin with the
Angiosperms, from the Mesozoic Cycadophyta.

The tendency, therefore, of modern work on the palaeontological record
of the Seed-plants has been to exalt the importance of the Fern-phylum,
which, on present evidence, appears to be that from which the great
majority, possibly the whole, of the Spermophyta have been derived.

One word of caution, however, is necessary. The Seed-plants are of
enormous antiquity; both the Pteridosperms and the more highly organised
family Cordaiteae, go back as far in geological history (namely to the
Devonian) as the Ferns themselves or any other Vascular Cryptogams. It
must therefore be understood that in speaking of the derivation of the
Spermophyta from the Fern-phylum, we refer to that phylum at a very
early stage, probably earlier than the most ancient period to which
our record of land-plants extends. The affinity between the oldest
Seed-plants and the Ferns, in the widest sense, seems established, but
the common stock from which they actually arose is still unknown; though
no doubt nearer to the Ferns than to any other group, it must have
differed widely from the Ferns as we now know them, or perhaps even from
any which the fossil record has yet revealed to us.

iii. THE ORIGIN OF THE HIGHER CRYPTOGAMIA.

The Sub-kingd