566 TRANSACTIONS OF SECTION K. 
is already seen normally each year in Z. inundatum. And this mode of life of 
Phylloglossum begins, as Thomas has shown, with its embryo. This appears 
to me to be a rational explanation of the ‘protocorm’ of Phylloglossum; ‘but it 
robs the plant of much of its theoretical interest as an archaic form. 
The phylum of the Sphenophyllales was originally based on certain slender 
straggling plants of the genus Sphenophyllum found in the Paleozoic Rocks; 
but they apparently died out in the Permian Period. Your native genera 
T'mesipteris and Psilatum were ranked by earlier botanists with the 
Lycopods, but a better acquaintance with their details, and especially the 
examination of numerous specimens on the spot, indicated a nearer affinity for 
them with the Sphenophyllales. It was Professor Thomas who in 1902 first 
suggested that the Psilotaceee might be included with the Sphenophylle in the 
phylum of the Sphenophyllales, and I personally agree with him. Dr. Scott, 
however, dissents, on the ground that the leaves are persistently whorled in the 
sphenophylls, while they are alternate in the Psilotacew; and while the former 
branch monopodially the latter dichotomise. But since both of these characters 
are seen to be variable within the not far distant genus Lycopodium, the differ- 
ences do not seem to me to be a sufficient ground for keeping them apart as the 
separate phyla of Sphenophyllales and Psilotales. Whatever degree of actual 
relation we trace, such plants as Z'’mesipteris and Psilotum are certainly the 
nearest living representatives of the Sphenophyllee, a fact which gives them a 
special distinction. The Psilotaceze also stand alone in the fact that they are 
the only family of the Pteridophytes in which the gametophyte is still unknown. 
They produce spores freely, but there the story stops. Any young Australian 
who hits upon the way to induce these recalcitrant spores to germinate, and to 
produce prothalli and embryos, or who found their prothalli and embryos in the 
open, would have before him a piece of work as sensational as anything that 
could be suggested. Further, I am told that Z'’mesipteris grows here on the 
matted stumps of Z'odea barbara. I shall be alluding shortly to the fossil 
Osmundacee. May we not venture to fancy the possibility of some fossil 
Osmunda being found which has embalmed for us among its roots a Mesozoic 
or even a Tertiary Sphenophyll? And thus a link might be found between the 
Paleozoic types and the modern Psilotacez, not only in time, but even in 
character. 
We pass now to the last phylum of the Pteridophyta, the Filicales. I am 
bound to say that for me its interest far outweighs that of the others, and for 
this reason. That it is represented by far the largest number of genera and 
species at the present day, while there is a sufficiently continuous and rich 
succession of fossil forms to serve as an efficient check upon our comparative 
conclusions. 
Since 1890 it has been generally accepted that the Kusporangiate Ferns (those 
with more bulky sporangia) were phyletically the more primitive types, and the 
Leptosporangiate (those with more delicate sporangia) the derivative, and in 
point of time later. The fossil evidence clearly upholds this conclusion. But, 
further, it has been shown that the character of the sporangium is merely an 
indicator of the general constitution of the plants in question. Where it is 
large and complex, as in the Kusporangiates, all the apical segmentations are, 
as a rule, complex, and the construction of the whole plant relatively bulky. 
Where the sporangium is delicate and relatively simple all the apical segmenta- 
tions follow suit, and the construction of the plant is on a less bulky model. 
On this basis we may range the Ferns roughly as a sequence, starting from 
relatively bulky types of the distant past, and progressing to the more delicate 
types of the present day. The large majority of the living species belong 
naturally to the latter. But the former are still represented by a few genera 
and species which, like other survivals from a distant past, are frequently of 
very restricted distribution. 
An interesting feature of the Australasian Flora is that a considerable 
number of these relatively ancient forms are included in it. Thus the 
Marattiacee are represented by one species of Alarattia and one of Angiopteris. 
Though in themselves interesting, they will be passed over without special 
remark, as they are very widely spread tropical forms. 
All the three genera of Ophioglossacez are included, there being two species 
of Ophioglossum and two of Botrychium, while Helminthostachys is recorded 
