v] 



LABOULBENIALES 



179 



A trichogyne, trichophoric cell and oogonium arc formed in the usual way 

 (fig. i,i). Accordingto Faull nuclear division takes place both in the oogo 

 nium, and in the trichophoric cell, and the partition between these two breaks 

 down so that a long cell containing a row of four nuclei is formed (fig. 145 a). 



Fig. 142. Amorphomyces Fala- 

 griac Thaxter ; paired spores ; 

 after Thaxter. 



Fig. 143. Amorphomyces Falagriac Thaxter; male and 

 female individuals; a. young, b. mature; after 'I'll, i . r. 



Walls cut off the upper and the lower nucleus, and a 

 central binucleate cell is left, the lower nucleus of which 

 is presumably a daughter of the oogonial and the upper 

 of the trichophoric nucleus. These divide simultaneously 

 and a binucleate inferior sterile cell is separated from the 

 binucleate fertile cell. This in turn divides to form the 

 ascogenic cells, from which the asci are to develop, and 

 these and the asci which they produce are therefore 

 binucleate. The two nuclei in the ascus fuse and their 

 union is regarded by Faull as the only nuclear fusion 

 which occurs in this very curious life history. Meiosis 

 then takes place, followed by the third division. The 

 upper daughter nuclei of this division degenerate and 

 around the lower nuclei spores are organized. In each 

 spore the nucleus divides once and a transverse septum 

 is formed. Faull describes four chromosomes (fig. 145 c) 

 at ever)- sta^e but figures an apparently larger number in 

 the first division in the ascus where the structures repre- 

 sented are evidently gemini (fig. 145 /;). 



1 he Laboulbeniales are subdivided by Thaxter ac- 

 cording to the method of formation of the male cells, 



Fig. 144. .hiiorpho- 

 Falagriac 

 Thaxler ; male and 

 female individuals, 

 the latter with peri- 

 thecium containing 



re ; aftei I 

 ter. 



12 — -2 



