1922] DUFF—GEOGLOSSACEAE 277 
“functions” of a veil. Although he does not say so explicitly, it 
is a fair inference that Dirrricu considered this thalloid invest- 
ment of the young Baeomyces fructification and the inclosing mem- 
branes of Miirula and of Leotia homologous, for he implicitly 
adduces this as evidence of the Geoglossacean affinities of Bae- 
omyces. DITTRICH’s conclusions were based upon the description of 
the development of the fructification of this lichen given by KRABBE 
(16). NurenBuRG (18) re-examined more recently some of the forms 
with which KraBBeE worked, and the results recorded in his paper 
present even more interesting parallelisms to the conditions prevail- 
ing among some of the Geoglossaceae. 
In Icmadophila aeruginosa the covering of the ascocarp is more 
distinct and more persistent than in Baeomyces. Figs. 1 and 2, 
taken from NIENBURG, represent sections of very young fruits of the 
former species. Here it may plainly be seen that the superficial 
layer of the thallus grows into an envelope for the young ascocarp 
and incloses it until it has attained considerable size, after which 
the growth of the ascocarp becomes too rapid for the extension of 
the epithecial tissue, which then ruptures. The fructification does 
not subsequently become covered with any other tissue which might 
be compared to a veil, and the hymenium therefore develops exoge- 
nously. As has already been indicated, however, the point of impor- 
tance in this connection is not the origin of the hymenium, but only 
the occurrence of an envelope which incloses the entire ascocarp, 
and which constitutes a morphologically distinct organ of the fruit 
body. In the opinion of the writer, therefore, the envelopes of 
Baeomyces and Icmadophila are strictly comparable and homolo- 
gous with those of the Geoglossaceae. From this it follows that in 
any natural scheme of classification some lichens, at least those of 
the Baeomyces group, must be brought in with the angiocarpous 
Geoglossaceous forms, as also possibly some members of the 
Helotiaceae. 
II. Sexuality 
CUDONIA LUTEA 
It is in the youngest stages of Cudonia lutea that we find the 
beginnings of the hyphal system destined finally to give rise to 
asci. As we have seen, here there are differentiated from the 
