conjiuens and the Morphology of the Ascocarp. 335 
In this connexion he makes the interesting observation that 
a button-like granule is present on the middle of this basal 
wall of the conjugating tube in its younger stages on the side 
toward the macrocyst, and that this granule disappears in 
older stages. He notes also that it stains yellow with iodine 
and swells from two to three times its original volume when 
treated with caustic potash solution. 
After the formation of the conjugation-tube the macrocyst 
swells to two or three times its original volume. Later, 
branches arise from its surface as papillae, and grow out, 
piercing between the vegetative enveloping hyphae which are 
already present. These branches at their point of origin are 
much thicker than the paraphyses. They are very crooked 
and soon become septate. 
Kihlmann believed that the asci were developed from the 
ultimate ramifications of these branches, but he was not able 
to trace the connexion directly from macrocyst to ascus. 
As these ascogenous branches develop, the macrocyst becomes 
emptied and vesicular and is not recognizable in the old fruit. 
At the time when the ascogenous hyphae begin their develop¬ 
ment, the antheridium and conjugation-tube are still full of 
protoplasm, which is sometimes very vacuolar. Kihlmann 
suggests the possibility that the basal wall of the conjugation- 
tube may become swollen, as do the cross-walls of the 
trichogyne in Collema , and that the disappearance of the 
granule mentioned above may be associated with this 
change. 
As to the homologies of the parts concerned, Kihlmann 
agrees with De Bary that the macrocyst is an ascogonium, 
the paracyst an antheridium, and the branches of the macrocyst 
are ascogenous hyphae. The whole structure is similar to 
that in Collema as described by Stahl, with the difference 
that in Pyronema the trichogyne is reduced to a single cell, 
and the ascogonium is also unicellular. The development 
of several ascogonia to one ascus-fruit is also found in Physrna 
and Collema. He also considers that the development of the 
male element as an antheridial branch in Pyronema , and as 
