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RESEARCHES ON FUNGI 



a 



I 



m 



71 



o 



A 



Fig. 96. — Sporobolomyces roseus. The nucleus during spore-production by a yeast 

 cell. Cultures made on malt-agar. Cells fixed with formalin-acetic-alcohol 

 and stained with iron-alum haematoxylin. a, a yeast cell with a sterigma on 

 which a rudimentary spore has begun to develop ; b, a similar yeast cell with 

 an older spore ; in both a and b the yeast cell contains a single nucleus and the 

 spore no nucleus ; c-h, a series of yeast cells bearing young spores, showing 

 stages in the division of the nucleus which passes up into the sterigma and 

 there becomes constricted into two daughter nuclei ; i-m, a series of yeast 

 cells bearing mature spores, the spore and the yeast cell each contain a single 

 nucleus ; n and o, two yeast cells after the discharge of the spore, each contains 

 a nucleus ; p, an old and exhausted yeast cell which may have discharged 

 2-4 spores, it now contains a large vacuole and a degenerate nucleus. Drawn 

 by A. H. R. Buller and Ruth Macrae. Magnification, 2234. 



