I 



KEYS TO THE COMMONER GENERA OF SACCHAROMTCETALES 359 



Normally not producing hyphae or only meagerly. 



Asexual reproduction by fission. Schizosaccharomyces 



Asexual reproduction by budding. 



Spores hat-shaped (see also species of Endomyces) . 



Buds produced from all sides of the cells. Hansenula 



Budding bipolar, i.e., from opposite ends of the cells. 



Hanseniaspora 

 Spores round with weakly or strongly verrucose walls, one, rarely two per 

 ascus. 

 Buds produced from all sides of the cells. Debaryomyces 



Budding bipolar (mostly), buds with a narrow base. Spores with an 

 equatorial ridge. No completed conjugation, though rudimentary 

 conjugation tubes are produced. Schwanniomyces 



Budding bipolar, but with a broad base. Spores without equatorial ridge. 

 Zygotes produced by union of a mother and a daughter cell. 



Nadsonia 

 Spores round to oval, smooth, one to four per ascus. Conjugation taking 

 place between pairs of ascospores in the ascus. Vegetative cells large, 

 with bipolar buds with broad base. Saccharomycodes 



Spores round to oval, smooth, one to four per ascus. Conjugation occurring 

 immediately before ascus formation or between vegetative cells in 

 colonies arising from germination of the spores. Not forming a thick 

 surface layer on beer wort. Fermentation of glucose marked. 



Saccharomyces 

 Spores round to angular, one to four per ascus. Conjugation before ascus 

 formation or unknown. Forming a thick surface layer almost imme- 

 diately on beerwort. Fermentation feeble or lacking. 



Pichia 



Key to the Commoner Genera of Family Torulopsidaceae 



(Based upon Lodder, 1934; Diddens and Lodder, 1942) 



Not forming true mycelium. Cells mostly single or in irregular groups. 



Subfamily Torulopsoideae 

 Cells prevailingly limoniform, with bipolar budding. Kloeckera 



Cells prevailingly triangular, budding at the three angles. 



Trigonopsis 

 Cells prevailingly flask-shaped, budding mainly at the broader basal part. 



Pityrosporum 

 Cells round, ovoid or cylindrical. 



Producing a thick surface growth on beerwort. No fermentation of glucose. 

 Buds often separating from mother cells by fission. Schizoblastosporion 

 Buds separating from mother cells in the usual manner. 



Mycoderma 

 Not producing a thick surface growth on beerwort. Fermentation of glucose 

 in some species, no fermentation in others. Torulopsis 



Forming pseudomycelium or true mycelium. Many species pathogenic to 

 animals. 



Subfamily Mycotoruloideae 

 Pseudomycelium or true mycelium, reproduction by budding. 



Cells often abruptly pointed, under aerobic conditions strong acid produc- 

 tion. Brettanomyces 



