Developments of the Oophyte in Trie Romanes. 271 
on the prothalli of species of Trichomanes , merely remarking, 
by way of preface, that the characters to be described fail 
under two heads : normal characters , including the develop- 
ment of the prothallus, formation of sexual organs, &c. ; and 
abnormal characters , including the phenomena of apospory 
and apogamy. Further, observations on sporophytic budding 
and oophytic budding by means of gemmae will be described. 
I propose, first, to describe a species in which the course of 
development shows but slight deviations from that which is 
normal for Ferns generally, viz. 
Trichomanes Pyxidiferum, Linn. 
Description of Protonema^. — This plant produces mature 
spores in the normal manner. They may germinate in the 
sporangium, or, having escaped from the sporangium, in the 
cup-shaped indusium, as has been described in other species 1 2 . 
On the mode of normal germination I have no details to add 
to those given by Mettenius, Goebel, and others. The result of 
germination is a much-branched, filamentous, protonema-like 
prothallus, coarser in texture than that of an average Moss, 
from which it can therefore be readily distinguished. The 
filaments are partitioned by septa, which are usually trans- 
verse, into cells, of which the length is not greatly in excess 
of the breadth, while a central swelling gives them a barrel- 
like form. Of the lateral branches (of which each cell may 
produce one, though it is by no means constantly developed), 
some retain and repeat the characters of the parent-filament, 
1 The material upon which these observations are based was derived from the 
collection in the Royal Gardens, Kew, where the method of cultivation of the 
Filmy Ferns in closed wall-cases and at a moderate temperature has attained signal 
success. It may be objected that it is impossible to be sure of the identity of 
species in cultures conducted in cases containing more than a single species ; but I 
have made observations on the aposporous prothalli of the same species (which are 
described below) ; others on prothalli produced by germination from spores still in 
the sporangium or sorus ; and these correspond so closely in character to the dense 
protonemal mat which was found overgrowing the stump, on which the specimen 
in question was cultivated, as to leave no doubt in my mind that the prothalli now 
described are actually those of Trichomanes pyxidiferum. 
2 Goebel, 1 . c. p. 92. 
