176 



PYRENOMYCETES 



[CH. 



All the cells are uninucleate. The female cell is called by Thaxter a 

 carpogonium or carpogonic cell in conformity with the term used for the 

 Red Algae, but it obviously corresponds to the cell in which fertilization is 

 now known to occur in other Ascomycetes and will therefore here be termed 

 the oogonium. 



In Stigmatomyccs Baeri the trichogyne is simple (fig. 136^, e) but in 

 many other members of the group it undergoes frequent septation and 

 branches freely. The apices of the branches are alone receptive and may 

 straight or spirally coiled (fig. 1 37). However elaborate, the trichogyne quickly 

 disappears, collapsing and breaking off as soon as its function is fulfilled. 



In endogenous species the sperms are shot direct on to the trichogyne or 

 carried to it by the water which ordinarily surrounds these filaments when 

 the hosts are hiding in moist places. In Zodiomyces on the other hand, 

 where the spermatia are formed externally, they fall off the parent branches 

 on to the cup-shaped receptacle, and there appear to be sought by the 

 trichogyne which is at first bent over (fig. 138 a) and later lifts itself after a 

 spermatium has become attached (fig. 138^). 



Fig. 137. Ci?'«/jowy<r« zi^r/zVzV/a/zw Thaxter ; after Thaxter. Fig. 138. Zodiomyces vortieellarius 



Thaxter ; trichogyne a. before and 

 b. after attachment of spermatium ; 

 after Thaxter. 



In any case numerous male cells reach the trichogyne and, though the 

 actual process of fertilization has not yet been seen, it appears likely that 

 it is accomplished. 



Afterwards the oogonium divides into three superposed cells, the sterile 

 inferior cell, the sterile superior cell and a fertile cell lying between the two 

 (fig. 136^, Ji). This middle cell cuts off a secondary sterile cell below 

 (fig. 136/) which like the other sterile cells is eventually destroyed. It then 

 divides longitudinally into four "ascogenic'' cells, two of which are shown in 



