The Sporangia of Stauropteris oldhamia. iig 
commonly occurs, was a fertile frond, consisting of a highly 
compound rachis, without leaflets. 
The sporangia were borne on the numerous fine ultimate 
ramifications of the rachis, each sporangium being seated 
terminally on a long branchlet. 
The sporangia have a terminal stomium, but no annulus. The 
wall is several cells thick. 
The numerous spores are spherical and of the tetrahedral or 
radial type. 
Williamson, in 1874, discussed the question whether his 
Rachiopteris oldlmmia was a Fern or a Lycopod, and rightly came 
to the conclusion that the balance of evidence pointed to its being 
a Fern, though, as already mentioned, he was puzzled by the 
absence of leaflets. The Lycopods no longer come into the 
question, but we may well hesitate whether to refer our fossil to the 
true Ferns or to the Pteridospermeae. 
The general structure of the rachis is altogether Fern-like, but 
not more so than in a typical Pteridosperm such as Lyginodendron. 
The scalariform structure of the tracheides might be cited as a 
Filicinean character, but this is really of no weight; in the foliar 
bundles of Medullosa anglica, for example, scalariform tracheides 
completely replace the pitted elements which are so abundant 
in the steles of the stem.' From the characters of the rachis, in 
fact, no conclusion can be drawn. The sporangia bear a general 
resemblance to exannulate sporangia of Ferns, but present no 
features sufficiently characteristic to settle the question, especially 
while we are still so ignorant of the structure of the pollen-sacs of 
the Pteridosperms. The way in which the sporangia are borne, 
terminating long and slender branchlets of the rachis, cannot 
probably be paralleled among recent Ferns; among fossils the 
nearest known analogy is offered by the fructification of Zygopteris , 2 
where the sporangia are likewise borne terminally, though on much 
shorter ultimate branches of the rachis than in our plant. 
Zygopteris and the other Botryopterideae still rank among true 
Ferns, though their position is not, perhaps absolutely secure. On 
present evidence the systematic position of Stauropteris must 
remain an open question. That it shows affinity with the Ferns is 
certain, but it would not be surprising to find that, like so many 
1 Scott, Structure and Affinities of Fossil Plants from the 
Palaeozoic Rocks, III On Medullosa anglica, Phil. Trans. 
R. S., B. vol. 191 (1899), p. 95. p 
8 Renault, Cours dc Bot. Fossile, Vol. 3, PI. 16, Fig. 3, 1883. 
