286 



YEASTS AND YEAST-LIKE FUNGI 



Cryptococcoideae, Cryptococcus. Most of the asporogenous yeasts 

 without pseudomycelium will be found to belong to one of two genera, 

 Cryptococcus and Mycoderma. The latter forms a heavy pellicle on 

 liquid media, the former no, or only a slight, film. In some of the 

 older literature Torula is used as the generic name rather than Cryp- 

 tococcus. This is incorrect. Most mycologists use the name Torula 

 to refer to certain of the Dematiaceae. See page 111. Although 

 most workers have given up the generic name Torula for yeasts, there 



a 1? c d 6 f 



Fig. 113. Vegetative cells of yeasts: a, Nadsonia fulvescens; b, ilansenula 



anomala; c, Pichia membranaefaciens ; d, "Torula cremoris" ; e, Rhodotorula 



glutinis; f, Cryptococcus pulcherrimus. 



is a difference of opinion as to the proper name to replace it. Most 

 medical mycologists use Cryptococcus, but nearly all industrial work- 

 ers who have abandoned Torula use Torulopsis. To use any one of 

 these three generic names thus goes contrary to current usage. We 

 have no choice but to adopt the generic name which seems to us to 

 be in accordance with International Rules of Nomenclature, namely 

 Cryptococcus. 



Cryptococcus is a budding yeast with little or no pseudomycelium. 

 Essentially it is very like Saccharomyces except that ascospores are 

 never formed and there are non-fermenting as well as fermenting 

 species. Cells of most species of Cryptococcus are spherical or nearly 

 so, but in some they are ovoid or elongated. In many strains of 

 several species of this and other genera of asporogenous yeasts, abor- 

 tive copulation tubes are formed as in Torulaspora.^® See page 283. 

 Spore formation, however, does not follow this abortive attempt at 

 copulation as it does in Torulaspora. This tendency to form abortive 

 copulation tubes may be increased by exposure of cells to camphor. 



