PHYLOGENY OF THE YEASTS 



141 



55. Mycelium 

 in Endomyces fibu- 

 liger Forming a 

 Number of Yeast- 

 Like Bodies. 



yeasts in that yeasts are reduced to the state of isolated cells while 

 the E. fertilis remains in a mycelial condition. 



With the genus Endomyces, one begins to approach the yeasts. 

 Endomyces fibuliger, discovered by Lindner, shows striking resem- 

 blances to Eremascus fertilis. It differs, however, 

 by that fact that the mycelium formed from 

 uninuclear cells gives birth, by budding, to a 

 series of yeast-like structures (Fig. 55) which sug- 

 gests that this fungus is intermediary between 

 the yeasts and Eremascus. Under certain con- 

 ditions, it is able to vegetate exclusively with the 

 form of yeasts. E. fibuliger, on the other hand, 

 produces conidia which form themselves by bud- 

 ding and are able to be compared, to a certain Fig 

 extent, with the "durable cells" of yeast. Finally, 

 it furnished numerous ascs very similar to those 

 of Eremascus which contain only 4 ascospores. 

 These ascs are formed often simply by budding of the elements, but 

 in many asces, they form after attempts at copulation at the expense 



of an anastomosis which occurs be- 

 tween two neighboring cells taking 

 place in the following manner: Two 

 units of the mycelium send out little 

 rootlets. These anastomose but the 

 wall which is formed between them 

 does not break down and, in many 

 cases, there is no mixture of the cell 

 contents. Generally one of the pro- 

 tuberances stops developing, the other 

 elongates, bends itself toward the first 

 and forms by a swelling, a tetrasporous 

 asc. (Figs. 56, 1, 2, 3, 5, and 6.) In 

 the meantime the two rootlets develop 

 into an asc. In some cases, the two 

 protuberances progress side by side, 

 Fig. 56. Different Stages in the without anastomosis, each forming a 



swelling which becomes the mother 

 cell of an asc; these two cells, thus 

 formed, bind themselves one to the other by a sort of copulation 

 canal in which the wall is not broken down. It also happens that 

 the extremities of a filament, formed by the walling off of a chain of 

 cells which swell up, transforms itself into an asc. Often, in this 

 case, anastomosis is often noticed binding the ascs two by two. 



