276 YEASTS AND YEAST-LIKE FUNGI 



Eremascus, Endomyces, and Endomycopsis. These genera are of 

 interest mainly in that they obviously connect the yeast with the 

 other Ascomycetes. Like the other Ascomycetes, they possess a 

 well-developed true mycelium, and as in the yeasts the ascospores 

 are formed in yeast-like cells without the formation of binucleate 

 ascogenous hyphae. Arthrospores are formed in Endomyces. In 

 Endomycopsis, in addition to vegetative growth by mycelium, blasto- 

 spores are produced which bud off the mycelium and these may 

 continue to proliferate by budding as in the ordinary yeasts. See 

 Fig. 13. Recently ^^ it has been demonstrated that Endomycopsis 

 fibuliger has the ability to excrete considerable quantities of amylase. 

 The use of this organism instead of malt for the saccharification of 

 mashes has given higher yields of fermentable sugar. Industrial 

 applications are obvious. See page 337. Endomycopsis is often in- 

 cluded in Endomyces. 



Schizosaccharomyces. The genus Schizosaccharomyces seems 

 mainly to be a group of tropical yeasts. Species have been isolated 

 from various tropical fruits, from African beer made from millet, 

 from Javanese, Formosan, and Jamaican molasses, from soil, and 

 from various insects. This genus forms four to eight spores by 

 isogamous conjugation. See Fig. 109 for the vegetative reproduction 

 by fission which is characteristic of the genus. Stelling-Dekker uses 

 the term "oidia (arthrospores) formation," rather than fission. Oc- 

 casionally a cell splits into more than two cells but usually the 

 fission is binary. 



Saccharomyces. The genus Saccharomyces includes most of the 

 yeasts of industrial importance. Vegetative reproduction is by bud- 

 ding. Pseudomycelium in most species is produced only in giant 

 colonies or in agar slant cultures several months old. Mycelium 

 appears in scattered strands at the edge of the growth. Saccharo- 

 myces is a typical diplobiontic yeast. The spores are round and 

 two to four are found per ascus. A key derived from SteUing-Dekker 

 is given for determination of species. 



KEY TO THE SPECIES OF SACCHAROMYCES 

 (Adapted from Stelling-Dekker) 



1. Fermenting glucose and galactose. 



a. Long pseudomycelium in young wort culture. S. dairensis 



b. Cells single or in twos in young wort cultures. 



I. One spore per ascus. S. unisporus 



II. Several spores per ascus. S. globosus 



