296 
WILLIAM H. BROWN 
the migration of the nuclei but denied the presence of a fusion of 
nuclei in the ascogonium. In the variety inigneum there appears to 
be neither a fusion of antheridium and trichogyne nor of nuclei in the 
ascogonium. Even though some of the above results may be due to 
misinterpretation it would still seem that Pyronema confluens may 
develop in a variety of ways. Some of the differences, such as those 
described by Van Tieghem, appear to be due to the influence of 
external conditions. Others, however, such as those described in this 
paper between the normal form and the variety inigneum may repre- 
sent permanent varieties. 
The absence of the fusion between the trichogyne and antheridium 
in some of Van Tieghem's cultures and in the variety inigneum prove 
that this is not necessary for the development of the ascocarp of 
Pyronema, while Claussen's results, together with the apparent 
absence of a fusion of nuclei in the ascogonia of the variety inigneum 
would seem to show that development can also occur without this 
nuclear fusion. These results, however, do not prove that a fusion of 
nuclei never occurs in the ascogonium. In view of the large number 
of pteridophytes in which apogamy has been induced, these results 
would not be very surprising even though it had been proved that in 
some cases a sexual fusion of nuclei did occur in the ascogonium. It 
may be said, however, that the development of Pyronema without a 
fusion of the antheridia and trichogynes or a fusion of nuclei in the 
ascogonium, together with the large number of cases among the 
Pezizineae in which different workers have failed to find a nuclear 
fusion in the ascogonium (see Brown, '11, and Claussen, '12), is not 
in favor of the view that such a fusion of nuclei does occur. Another 
argument against this fusion would seem to be afforded by the pres- 
ence, in the ascogonia and in various other stages of the life history 
of the variety inigneum and of Lachnea scutellata (Brown, '11), of 
appearances, during the division of the nuclei, which simulate fusion 
quite closely. It is, of course, not safe to assume that conclusions 
drawn from one form will apply to another, but, as previously pointed 
out (Brown, '11), in view of the fact that in those Pezizineae in which 
divisions of the nuclei have been described in the ascogonia, these 
divisions show stages having the appearance of fusing nuclei, it would 
seem necessary to study the divisions in the ascogonia and to dis- 
tinguish between true and apparent fusions before the occurrence of 
such a fusion can be regarded as proved, and, so far as the writer 
