Developments of the Oophyte in Trichomanes. 283 
most irregular prothalli is the formation of gemmae , or, as 
Cramer termed them, conidia. Such organs, borne on the 
oophyte in the Hymenophyllaceae on the tips of flask-shaped 
pedicels 1 , were described by Mettenius 2 in Trichomanes incisum 
var. Krausii\ but it does not appear that their germination 
was traced by him, or their true nature established ; also, 
judging from our present knowledge of similar forms, it would 
seem probable that the gemmae observed by Mettenius 
were immature. Cramer, working with material of un- 
certain origin, but presumably belonging to some species 
of Trichomanes 3 , described spindle-shaped gemmae, borne on 
flask-shaped stalks inserted on a filamentous, protonema-like 
growth ; this protonema also produced antheridia, archegonia, 
and embryo plants, similar in their main characters to those 
described by Mettenius for species of Trichomanes. He further 
succeeded in tracing the germination of these gemmae, and thus 
established that they are vegetative organs of propagation of 
the oophyte. Quite recently Goebel 4 has described similar 
observations made on various Ferns, notably on Vittaria par- 
vula and Monogramme paradoxa , in which the formation of 
spindle-shaped gemmae in large numbers on the margin of the 
thallus has been seen, and, in the former case at least, their 
germination noted. He has also described organs, probably 
‘ sterigmata,’ borne on the prothallus of an unrecognised species 
of Trichomanes , and in various species of Hymenophyllum the 
formation of adventitious buds, different it is true in their form, 
but subserving the function of vegetative propagation of the 
oophyte. As no one of these writers has given a record of 
the development of the gemmae, illustrated by figures, in any 
definite species of Trichomanes , it will not be superfluous to do 
so here. 
1 ‘ Sterigmata ? of Goebel, 1 . c. p. 82. 
2 1 . c., p. 493. Compare figures in Plate v. 
3 Denksch. Schw. Nat. Ges. 1880. This presumption is now strongly sup- 
ported by the facts which have recently been published by Goebel, and by my 
own observations. 
4 Op. cit. 
X 
