confluens and the Morphology of the Ascocarp. 345 
The nuclei of the antheridium are of about the same size 
as those of the oogonium. The protoplasm of the antheri¬ 
dium stains much less densely than that of the oogonium, 
owing perhaps to the absence of accumulated reserve materials. 
As a result the nuclei are more sharply differentiated in the 
antheridium, since they stain quite as intensely as those in 
the oogonium. These sexual nuclei are relatively large and 
very clearly defined in their structure. They contain a very 
small spherical nucleolus which appears bright red when the 
triple stain is used. The chromatin forms a conspicuous net 
of granules and fibres staining blue or violet with the same 
triple stain. For those who are still sceptical as to nuclear 
structures in the Fungi it should be said that these sexual 
nuclei of Pyronema are quite as conspicuous and quite as 
available for study by their staining qualities as are the 
nuclei of many of the higher plants. Even prior to the 
fusion of the antheridium and conjugating tube, short branch- 
lets are to be found budding out from the stalk-cells of the 
oogonium and the neighbouring vegetative cells, and these 
later grow upwards to form the hypothecium and paraphyses. 
Whether such branches arise also from the stalk cells of the 
antheridium is uncertain. They certainly are not present at 
this early stage, and later after the fertilization has been 
accomplished it is difficult to make out with certainty the 
origin of all the hyphae which are combined to form the 
young fruit-body. 
If we turn to the process of conjugation and fertilization in 
the sexual apparatus just described, it is apparent that to 
permit the union of the male and female cells in addition 
to the fusion already mentioned as occurring between the 
tips of the antheridium and conjugating tube, the breaking 
down of a second wall at the base of the conjugating tube 
between it and the oogonium is necessary. The first of 
these two fusions was discovered by the Tulasne brothers 
( 36 ) and studied fully by them and by Kihlmann ( 19 ). These 
investigators, however, were unable to observe the breaking 
down of the basal wall of the conjugating tube, and their 
