THE FUNGI WHICH CAUSE PLANT DISEASE 121 



Key to Genera of Saccharomycetacese 



Vegetative cells globose, ovoid, pyriform, etc. 

 Vegetative cells increasing by budding; 

 asci typically 3 to 4 spored. 

 Spores globose or ovoid. 

 Spores upon germination forming 

 typical yeast cells. 

 Ascus formation preceded by the 



conjugation of like gametes. 1. Zygosaccharomyces. 

 Ascus formation not preceded by 

 the conjugation of gametes. 



Spore membrane single 2. Saccharomyces, p. 121. 



Spore membrane double 3. Saccharomycopsis. 



Spores upon germination forming a 



poorly developed promycelium. 4. Saccharomycodes. 

 Spores pileiform or limoniform, costate 5. Willia. 

 Spores hemispheric, angular or irregular 

 in form, upon germination forming 



an extended promycelium 6. Pichia. 



Vegetative cells increasing by fission; asci 



8-spored 7. Schizosaccharomyces. 



Vegetative cells elongate, cylindric; spores 

 filiform, 



Asci 1-spored 8. Monospora. 



Asci 8-spored 9. Nematospora, p. 122. 



Saccharomyces Meyen 



Vegetative cells globose, ellipsoid, ovate, pyrifonn, etc., repro- 

 ducing by budding and remaining attached in short, simple or 

 branched pseudo-mycelial groups, at length separating; asci 

 globose, ellipsoid, or cylindric, 1 to 4-spored (typically 3 to 4- 

 spored), single or in chains; spores globose to ellipsoid, continuous. 



Many species, chiefly saprophytes. 



S. croci Roze is described as the cause of a crocus disease.^ 



From sorghum plants suffering from blight a yeast was isolated 

 by Radais.® This when inoculated in pure culture into healthy 

 plants produced the characteristic lesions and effects. 



