266 



YEASTS AND YEAST-LIKE FUNGI 



separated from the parent cell by constriction, they develop a cross- 

 wall in the pedicel. See Fig. 110. 



Fig. 109. Vegetative cells of yeasts: a, Schizosaccharomyces Pombe ; b, Zygo- 



saccharomyces Bailii; c, Saccharomyces guttulatus; d, S. cerevisiae; e, S. 



cerevisiae var. ellipsoideus ; j, S. jragilis. 



Fig. 110. Schizobastosporion Starkcyi-Henricii, showing reproduction by com- 

 bination of budding and fission. Redrawn from original pencil drawing pub- 

 lished by Starkey and Henrici, Soil Science, 23, 33 (1927). 



Sexual Reproduction. In addition to these methods of vegetative 

 multiplication, yeasts may reproduce by intracellular spore forma- 

 tion. These spores are somewhat like those of bacteria in that they 

 are more resistant to heat and drying than are the vegetative cells, 

 but unlike bacterial spores in that they are generally multiple and 



