ticle "On the present
position of Palaeozoic Botany", "Progressus Rei Botanicae", 1907, page
139, and "Studies in Fossil Botany", Vol. II. (2nd edition) London,
1909.) At the same time, the anatomical structure, where it is open to
investigation, confirms the suggestion given by the habit, and shows
that these early seed-bearing plants had a real affinity with Ferns.
This conclusion received strong corroboration when Kidston, in 1905,
discovered the male organs of Lyginodendron, and showed that they were
identical with a fructification of the genus Crossotheca, hitherto
regarded as belonging to Marattiaceous Ferns. (Kidston, "On the
Microsporangia of the Pteridospermeae, etc." "Phil. Trans. Royal Soc."
Vol. 198, B. 1906.)

The general conclusion which follows from the various observations
alluded to, is that in Palaeozoic times there was a great body of plants
(including, as it appears, a large majority of the fossils previously
regarded as Ferns) which had attained the rank of Spermophyta,
bearing seeds of a Cycadean type on fronds scarcely differing from the
vegetative foliage, and in other respects, namely anatomy, habit and the
structure of the pollen-bearing organs, retaining many of the characters
of Ferns. From this extensive class of plants, to which the name
Pteridospermeae has been given, it can scarcely be doubted that the
abundant Cycadophyta, of the succeeding Mesozoic period, were derived.
This conclusion is of far-reaching significance, for we have already
found reason to think that the Angiosperms themselves sprang, in
later times, from the Cycadophytic stock; it thus appears that the
Fern-phylum, taken in a broad sense, ultimately represents the source
from which the main line of descent of the Phanerogams took its rise.

It must further be borne in mind that in the Palaeozoic period there
existed another group of seed-bearing plants, the Cordaiteae, far more
advanced than the Pteridospermeae, and in many respects approaching the
Coniferae, which themselves begin to appear in the latest Palaeozoic
rocks. The Cordaiteae, while wholly different in habit from the
contemporary fern-like Seed-plants, show unmistakable signs of a common
origin with them. Not only is there a whole series of forms
connecting the anatomical structure of the Cordaiteae with that of the
Lyginodendreae among Pteridosperms, but a still more important point is
that the seeds of the Cordaiteae, which have long been known, are of
the