The Origin and Development of the Apothecium etc. 
421 
nucleus is unknown in any otlier organism. Nor is tliere a disintegration 
of female nuclei, as reported in Vaucheria, leaving only one to be fertilized. 
To Baur, following a Suggestion of Karsten, it seems raost probable 
that the first ascogone cell serves as the egg cell, the male nucleus fusing 
with the nucleus of the egg cell, and the fusion nucleus dividing to form 
nuclei which migrate into the remaining ascogone cells, the latter now 
functioning as auxiliary cells. From what I have observed, it does not 
seem likely that the ascogone is divided into an egg and auxiliary cells. 
At any rate, before we can know what actually does take place in such 
a structure, it is necessary that a very large number indeed of carpo- 
gones be traced with absolute certainty from their origin throughout 
their length and the complete history of the nuclear behavior noted in 
each case. This is indeed no small task, but it seems to me the only way 
of arriving at a safe conclusion. 
Fraser and Chambers (37) have suggested that in lichens, fertili- 
zation or its equivalent may actually be accomplished before the ascogone 
becomes septate. But this woiüd exclude all possibility of trichogynes 
and spermatia being functional sexual Organs, since my resiüts as well 
as those of others show that the carpogone is septate long before there 
is any fusion with a spermatium. Neither is there any evidence that 
the cells of the carpogone are sporophyte cells, that is, that there has 
been cell or nuclear fusion of any kind before the development of this 
organ. If fertilization could in any way have been accomplished before 
the development of the trichogyne, it would be difficult indeed to under- 
stand just what function could be assigned to this organ behaving as I 
have described it in Cöllema pulposum. 
Wainio (85) long ago argued that the many cross walls of the tricho- 
gyne oppose any consideration of its being a fertilizing organ. But Harper 
(51) has called attention to the fact that since in Pyronema two cross walls 
can be broken down to allow the male nuclei passage into the ascogone, 
there is no reason why the greater number of cross walls in the liehen 
trichogyne may not become perforated. Wainio thought it reasonable that 
the ascogones are nutrition reservoirs for spore formation and that the 
trichogynes are accidental elongations of the ascogones, and because of the 
accumulated substance in the ascogones, the trichogynes develop with 
greater vigor than the other parts of the apothecium. My results as well 
as those of others show that the ascogone, at least by the time the asco- 
genous hyphae are formed, does not contain any large amount of nutritive 
material, and that the vegetative hyphae furnish the nutrition for the 
developing fruit body. Van Tieghem (89) has had many adherents to 
