256 FAMILY OF SACCHAROMYCETACEAE 



grayish white color. The center is slightly concave with a surround- 

 ing surface of radial bands: The edge is very much indented. On Koji 

 gelatin in plates, the colonies are punctiform moist with a grayish- 

 white color. The gelatin is not liquefied. In streaks on the same 

 medium this yeast furnishes a thick white growth with an indented 

 border. 



SACCHAROMYCES COREANUS. Forma Major. Saito 



Isolated under the same conditions as the preceding one, this 

 yeast is scarcely distinguishable by its dimensions, which are, however, 

 a little larger. The cells are spherical or oval (8 to 12 JJL in diameter) 

 (Fig. 121, a) and cause the formation sometimes of short mycelial forma- 

 tions. The ascospores are 2 to 4 /j in diameter (Fig. 121, b). This 

 yeast forms no scum on a decoction of Koji. 



SACCHAROMYCES jORGENSENII. Lasche* 



This yeast was described by Lasche. 1 It possesses small round 

 or oval cells (2.5 to 5/u). The optimum temperature for sporulation 

 is 25 C.; the temperature limits are 8-12 and 26-30. At this 

 higher temperature, vegetation rapidly disappears. The ascospores 

 are spherical and very refractive. They are present ordinarily to 

 the number of 2 or 3, rarely 4, per asc. No scum formation has 

 been noticed. In old cultures, one may observe a scant ring formation 

 resembling that of a brewery yeast. Gelatin is slowly liquefied. Cul- 

 tures on streaks have a gray color with a regular edge. 



C. Third Sub-Group 



Yeasts fermenting dextrose and maltose but having no action 

 on saccharose or lactose. 



SACCHAROMYCES ROUXII. Boutroux 2 



This yeast was discovered in the juice of certain fruits. Its cells 

 are small, 4 to 5 ju, in diameter. They are spherical or ellipsoidal 

 and often arranged in chains. The ascs contain from 1 to 3 ascospores. 

 They are produced especially on nutrient fluids. This species pro- 

 duces no extended scum but simply small floating islands. 



1 Lasche", A. Saccharomyces Jorgensenii. Der Braumeister, Chicago, 1892, 

 and Zeitschr. f. d. ges. Brauw. 15, 1892. 



2 Boutroux, L. Sur 1'habitat et la conversation des levures spontanees. 

 Bull, de la soc. Linn, de Normandie, Vol. VII, 1883; Ann. de 1. sc. nat. Botan. 

 17, 1884. 



