od ie 
AK: oe 
Se ee 
K.—BOTANY. 181 
from some long-extinct stock, comparable, perhaps, to Kidston’s and 
Lang’s Psilophytales, though not necessarily on the same line. 
The significance of the Pteridosperms has perhaps been somewhat 
misunderstood. It now seems that they do not, as some of us once 
imagined, indicate the descent of the Seed Plants from Ferns, but 
rather show that the Seed Plants passed through a Fern-like phase; 
they ran a parallel course with the true cryptogamic Ferns, and, like 
them, sprang from some quite early race of land plants, such as Rhynie 
has revealed to us. But the phylum was never any more Fern-like 
than the Pteridosperms themselves. This, at least, is the view which 
now suggests itself, but our knowledge is still very meagre. We 
especially want to know more about the Devonian Spermophyta, for 
at present we have scarcely any evidence even of the existence of seeds 
in any Devonian Flora. Such data as we possess are all anatomical, 
and a disciple of Williamson must be on his guard against the risk 
of repeating the old mistake of the Brongniartian school. 
Having ventured so far into speculative regions, it may be well to 
return for a moment to the facts, and ask to what extent our knowledge 
of the Fern-like Seed Plants has advanced since the original discoveries 
of 1903-1906. I fear that there is not very much to record. We now 
have one or two additional species of Neuropteris bearing seeds, and 
also the probable seed of Heterangiwm. Further, we have various 
indications of the characters of the pollen-bearing organs in some 
Pteridosperm genera, though the documents, being mostly in the form 
of impressions, are deficient in detail. Such new information as has 
come to hand confirms in a satisfactory manner our former conclusions, 
but does little to extend them. 
On the anatomical side there has been more liveliness. We now 
know quite a number of Paleozoic plants, of varied structure, which 
have something in common with the better-established Pteridosperm 
families, Lyginopterideee and Medullosee, while they certainly have 
nothing to do with Lycopods, Horsetails, or Sphenophylls. We there- 
fore call them Cycadofilices or Pteridosperms. I prefer to use one name 
for them all and incline to the latter, for, while the plants are generally 
more or less Fern-like in structure, many of them show no special 
resemblance to Cycads. 
At present we know of no fewer than eight families, based mainly on 
anatomical characters, which we provisionally include under Pterido- 
sperms : 
1. The familiar Lyginopterideze (Lower and Upper Carboniferous). 
2. The Rhetinangium family, founded on Dr. Gordon’s new genus 
(Lower Carboniferous). 
3. The Megaloxyleew, discovered by Prof. Seward (Upper 
Carboniferous). 
4. The Calamopityes, recently enriched by Dr. Kidston with a new 
genus, besides new species (Lower Carboniferous). 
5. The Stenomyelon family, another of Dr. Kidston’s discoveries, 
described by him in conjunction with Gwynne-Vaughan (Lower 
_ Carboniferous). 
