344 Harper.—Sexual Reproduction in Pyronema 
lies in the long axis of the beak, and it gives very much the 
appearance of the piercing of the antheridial wall by the end 
of the beak, but taking the appearance and arrangements of 
the parts as a whole it is easy to see how Tulasne was led 
to the conclusion, that it is impossible to say whether the 
antheridium or the conjugation-tube is the more active in 
accomplishing the fusion. This mutual approach of the two 
cells is perhaps most conspicuous in surface views of the 
sexual organs such as Tulasne studied (see Fig. i). This 
mutual attraction and bending of both cells might be expected 
between equal gametes. In the bulk of Fungi which show 
antheridial branches it is the latter which are the active 
structures, and in their growth apply themselves closely to 
the surface of the oogonium, but here the female cell has 
also developed an organ—the conjugating tube—which is at 
least equally active with the antheridium in effecting the 
union. 
The mature sexual apparatus shows nothing further than 
has been already mentioned in the development of its parts. 
Its structure may be summarized as follows: 
The oogonium is a spherical or flask-shaped cell filled with 
dense protoplasm and many nuclei which are very much 
larger than those of the ordinary vegetative cells. Its stalk 
consists of two or three broad disk-shaped cells of which the 
basal one is a part of the mass of thickened swollen cells 
forming the base of the rosette. The apex of the oogonium 
is continued into the narrow conjugating tube which curves 
upward to unite with the end of the antheridium. The 
antheridium is a curved club-shaped cell thickest near its 
upper end and tapering gradually to its base where it is 
continued into a stalk of one or more cells. The basal 
wall of the antheridium is as a rule somewhat higher up 
than that of the oogonium. It follows a somewhat oblique 
path upward, conforming rather closely to the surface of the 
oogonium, and its apex is even with, or reaches somewhat 
past, that of the latter. The mutual relation of these sexual 
cells in a typical case will be best understood from Fig. i. 
