46 
THE CLASSIFICATION OF D1SCOMYC ETES. 
Humana , Sarcoscypha, Aleuria , and likewise in Verpa , Helvella , 
and Morchella , while Helotium and the neighbouring genera 
Leotia , Mitrula, and Geoglossum presented a different mode of 
dehiscence. 
At this time, after the examination of a considerable number of 
Discomycetes, I am able to call the attention of mycologists to the 
necessity of separating this family into two very natural sections, 
according as to whether the mode of dehiscence is with, or without 
an operculum. I would call the first section by the name of 
Operculate Discomycetes, or simply Operculce , because in this section 
the opening of the asci takes place by the elevation of a little lid at 
its summit. The second I would call Inoperculate Discomycetes, 
or simply Inoperculce , because the exit of the sporidia takes place 
by a small bole, formed at the extreme summit of the asci, with its 
margin more or less elevated, but without any appearance of an 
operculum. 
There is no great difficulty in observing this dehiscence, 
although few authors mention it. A very little attention soon 
renders it quite familiar, and I consider its careful observation 
indispensable to a good classification of genera and species. 
In the first division, the Operculce, the dehiscence is accomplished 
by the formation of a circular slit at the summit of the ascus. 
The tension produced when at maturity by the increase of their 
growth causes them to rupture circularly at the summit, following 
the slit which is formed there, as I have previously pointed out in 
certain Ascoboli(“ M6m. surles Ascoboles,” p. 11, pi. 10, fig. xxxi 
and 8 and 9), throwing the operculum back by the sudden pro- 
jection of the contents of the ascus leaving it generally a little 
elevated, with one space open or sometimes almost closed. This 
operculum varies according to the form of the extremity of the 
ascus. It is convex, when it is round, as in certain Humaria and 
Byparobius ; it is flattened, when the ascus is truncate, as in 
Aleuria ; it is mammular in the centre, when the extremity 
presents a similar character to Ascobolus. 
When the ascus is larger, it often bends on each side, which 
causes it to appear oval or triangular, as often occurs in Saccobulus. 
In almost all cases it retains its round form very clearly when seen 
in front, and slightly raised when seen in profile. The circular 
slip is almost always horizontal, but in a few rare instances it is 
oblique, as in some species of Humaria. In one particular genus, 
so well named by Mr. Renny, Ascozonus , it is perpendicular, and 
this form caused me to doubt for a long time as to the true place 
this genus ought to occupy. If it be considered as a slit, it will 
come in the Operculce, and I am now of this opinion, in consequence 
of the great affinity existing between this genus and Byparobius. 
If it be considered as a simple rent of the apex of the ascus, which 
would not be capable of softening, it will enter into the second 
section, as I had at first thought. But I repeat such cases form 
very rare exceptions to the general rule. 
