53 
and Helmut tkostachys zeylaniea . 
prothallus found in the homosporous Lycopodiales. This con- 
clusion is essentially that at which Jeffrey 1 arrived as a result 
of a similar comparison. When however it is borne in mind 
how little is known of the variation of the characters of the 
gametophyte under altered conditions, it is clear that this can 
only be regarded as a provisional view. The results of ex- 
perimental cultures if critically interpreted might afford 
valuable additional evidence. 
In the above discussion the characters of the sporophyte 
have been left out of account. If indications of sufficient 
weight — to render the origin of the Ophioglossaceae from a 
Filicineous stock improbable, and to connect them closely 
with the Lycopodiales — were afforded by the sporophyte, the 
value of characters of the gametophyte as indicating relation- 
ship between large groups would have to be reconsidered. 
Such evidence in the present case would require to be 
sufficiently clear to override the indications of a Filicineous 
affinity afforded by the prothallus. In the author’s opinion 
such preponderating evidence has not been advanced, and it 
may indeed be questioned whether, in the case of this 
particular group, the characters retained by the gametophyte 
do not deserve to be given special weight. 
1 Loc. cit., p. 289. 
