Notes. 
169 
that the family is a relatively primitive one *. Bower places it in his 
group 1 Simplices,’ which on comparative grounds he regards ‘ as 
being relatively primitive and less specialized types of Ferns/ The 
records of Palaeontology show that the group is an ancient one. 
Senftenbergia from the Carboniferous and Klukia from the Jurassic 
are referred by Potoni6 2 to the family, whilst the living genus Lygodium 
dates from the Cretaceous. Apparently the family has undergone 
but slow modification. Hence, without committing ourselves to the 
view that gametophyte and sporophyte undergo modification at the 
same rate, have we not some warrant in looking for primitive characters 
in the prothallium ? 
In speaking of the prothallium of Schizaea I have preferred to 
compare it with an Alga rather than with the protonema of Moss, 
for it has appeared to me more suggestive of the former. But, in 
any case, the protonema of the Bryophyta is itself, in many respects, 
comparable with an Alga. The prothallium of Schizaea may be 
compared with the protonema of the Bryophyta, and we have, more- 
over, an additional point of resemblance to the Bryophyta in the free 
archegonial venter. But it is to be noted that the archegonium of 
Schizaea is carried upon a filament, whereas this does not appear 
to be the case in any known Bryophyte. The male plant of Bux- 
baumia makes the nearest approach to Schizaea in having the anthe- 
ridia directly borne on the protonema. But the stalked antheridium 
is protected by a leaf-like lobe (which is without chlorophyll), so that 
the filamentous character is not completely retained. In the female 
plant of Buxbaumia the protonema produces a more considerable 
gametophore, consisting of a small stem with a few simple leaves, 
which are also without chlorophyll. The archegonium is at the apex 
of the stem. Goebel ( 1 . c. p. 350) is inclined to consider Buxbaumia 
as a relatively primitive form which has remained at a stage that other 
Mosses have passed through. He suggests that such a form may 
have arisen from a filamentous Alga in which the branches that 
developed the sexual organs have become more complex. If this 
view be correct and Buxbaumia is not a form reduced in accordance 
with a supposed saprophytic habit (which Goebel regards as still 
unproved), we have an interesting form for comparison with Tricho - 
manes. Even if Buxbaumia be reduced, the gametophores of the 
1 Bower, Philosophical Transactions, 1900, B. Vol. 192, p. 123. 
2 Die natiirlichen Pflanzenfamilien, Th. I., Abt. 4, p. 371. 
