300 



YEASTS AND YEAST-LIKE FUNGI 



istically in groups of four (occasionally more) long slender cells. 

 These are arranged somewhat like an airplane with its outspread 

 W'ings. The investigation of Gruess indicates that these "airplane 

 forms" are produced by a growth in media of low nutrient value. In 

 ordinary sugar media as used for yeasts, only large oval budding 

 forms develop. But if the concentration of nutrients is greatly re- 

 duced, the form characteristic of the nectar growth also appears in 

 artificial cultures. Nadson and Krassilnikov suggest that the air- 

 plane form is an adaptation which has resulted from natural selec- 



FiG. 121. Sporobolomyces salmonicolor. Petri plate culture showing develop- 

 ment of '"mirror colony" on the lid. 



tion, enabling the yeast to aflhere easily to the hairs on insects and 

 so be transported to new flowers. 



The latter authors observed sectorial mutations to occur in giant 

 colonies, in some of which short filaments of true mycelium occurred 

 which developed globular conidia on slender lateral branches appear- 

 ing much as in the mold Verticillium. They also made cytological 

 studies and found but a single nucleus in all the various growth forms. 

 These findings should be confirmed. If they are not confirmed, there 

 seems to be no reason for not relegating species of Nectaromyces 

 to the genus Candida. 



Sporobolomyces and Bullera. The anascosporogenous yeasts de- 

 rived from the Basidiomycetes are classified in two families, the 

 Sporobolomycetaceae and the Rhodotorulaceae.^ The characteristics 

 of the families and the genera are given in the key on page 285. 



The peculiar characters of Sporobolomycetaceae were first recog- 

 nized by Kluyver and van Niel. If one inoculates a Petri plate 



