1922] DUFF—GEOGLOSSACEAE 269 
omyces, Sphyridium, and Icmadophila. He drew no distinction 
between the so-called ‘‘Primordialhyphen” of Usnea and the 
“generativen Hyphen” of Sphyridium and Icmadophila. In Bae- 
omyces, however, the carpogonia are so poorly defined that they 
are not separable from the “‘Primordialhyphen,” so to the entire 
system in Baeomyces he extended the term “‘generativen Hyphen.” 
Then, because of the evidently close natural relationship of Sphyrid- 
ium, Icmadophila, and Baeomyces, he adopted the designation 
“‘generativen Hyphen” in connection with these forms. It is to 
be understood, therefore, that the “generativen Hyphen” of 
Baeomyces are not exactly homologous with those of Sphyridium 
and Icmadophila. 
In the preliminary paper (10) the writer adopted the term 
“generative hyphae” rather than ‘“‘primordial hyphae” to desig- 
nate the pre-fertile threads of Cudonia and Spathularia. This was 
done because the Geoglossaceous forms appear to be more closely 
related to Baeomyces, Sphyridium, and Icmadophila than to Usnea. 
The occurrence of such a system of threads acting as precursors to 
the procarps is unusual, so far as the writer is aware, being found 
only in the disco-lichens,. and so may be considered of sufficient 
importance to warrant emphasis. 
The second developmental stage (fig. 4) shows a very definitely 
organized outer tissue, which has apparently been thrown up by 
the mycelial threads. By following through the series (figs. 4-7) 
this tissue may be seen to be identical with that later regarded as 
the veil. The veil in Cudonia, therefore, originates at a time when 
the ascocarp is nothing more than a cushion of mycelial threads with 
a core of generative hyphae, and can therefore be said to be present 
from the first. It is to be noted that at this stage a well marked 
clear zone separates the generative threads from the veil tissue. 
This clear zone contains only the remnants of the mycelial hyphae 
that once surrounded the generative threads. Fig. 5 illustrates 
the next developmental stage of Cudonia. Here the generative 
hyphae form an elongated mass of filaments of which the oldest are 
at the lower, and the newly formed elements, recently proliferated 
from them, are at the upper extremity. This upward growth of 
the generative threads has completely obliterated at the top the 
