Pteridospermeae 211 
association between the seed and the plant’. The structure of the 
seed of Lyginodendron, proved to be of the same general type as 
that of the Cycads, as shown especially by the presence of a pollen- 
chamber or special cavity for the reception of the pollen-grains, an 
organ only known in the Cycads and Ginkgo among recent plants. 
Within a few months after the discovery of the seed of Lygino- 
dendron, Kidston found the large, nut-like seed of a Neuropteris, 
another fern-like Carboniferous plant, in actual connection with the 
pinnules of the frond, and since then seeds have been observed on 
the frond in species of Aneimites and Pecopteris, and a vast body 
of evidence, direct or indirect, has accumulated, showing that a large 
proportion of the Palaeozoic plants formerly classed as Ferns were in 
reality reproduced by seeds of the same type as those of recent 
Cycadaceae®. 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? 
The general conclusion which follows from the various obser- 
vations 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, re- 
taining 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, 
1 FB, W. Oliver and D. H. Scott, ‘On the Structure of the Palaeozoic Seed, Lagenostoma 
Lomazi, ete.” Phil. Trans. Royal Soc. Vol. 197, B. 1904. 
3 A summary of the evidence will be found in the writer’s article “On the present 
position of Palaeozoic Botany,” Progressus Ret Botanicae, 1907, p. 189, and Studies in 
Fossil Botany, Vol. 1. (2nd edit.) London, 1909. 
® Kidston, ‘On the Microsporangia of the Pteridospermeae, etc.” Phil. Trans. Royal 
Soc. Vol. 198, 8. 1906. 
14—2 
