88 Recent Discoveries of Pteridophyte Prothalli . 
The prothalli of these two genera differ from that of Botrychium 
virginianuin, as described by Jeffrey in 1897 1 and B. Lunaria, both of 
which shew a tendency to a thick flattened form of prothallus, with in 
B. virginianuin the sexual organs on the upper surface. 
With regard to the bearing of the gametophytic characters 
upon the affinities of this isolated group, the Ophioglossaceae, the 
weight of evidence is distinctly on the side of a Filicinean ancestry. 
The apical growth, the structure of the archegonium, and the multi- 
ciliate spermatozoids (known in Botrychium aud Ophioglossuin 
peduticulosum) may be mentioned as the most important characters 
connecting this family with the Filicineae, and separating them from 
the Lycopodineae, the other group with which an affinity has been 
suggested. 
Close upon Dr. Lang’s preliminary account of his discoveries 
came the announcement of the finding of the prothallus of the very 
simple Lycopod JPhylloglossum , by Mr. A. P. W. Thomas, 2 of 
Auckland, N.Z. 
It turns out to be of the Lycopodium cernunm type and lends 
support at once to the belief that this type is the primitive form 
of Lycopod prothallus, and to the view that Phylloglossum itself is 
a relatively primitive Lycopod. 
Thus within five years the discoveries of the prothalli of no less 
than eight species, and two, if not three, genera belonging to the Ophio- 
glossacete and homoporous Lycopodineae have been announced. 
The curious epiphytic Australian genus Tmesipteris is the only 
type belonging to these groups of whose gametophyte, &c., we are 
still ignorant, if we assume that Lang’s isolated prothallus is really 
that of Psilotum. 
1 Transactions of the Canadian Institute, 1896-7. 
2 Proc. Ro}\ Soc. 1902. 
