i8o 



RESEARCHES ON FUNGI 



yeast cells remain oval or ellipsoid in form and do not become 

 branched like hyphae or irregular in shape, and the sterigmata are 

 short, conical, simple and unbranched, like the sterigmata on the 

 basidia of the Hymenomycetes. 



(2) When a spore is produced from a yeast cell at the edge of 



Fig. 88. — Sporobolomyces roseus. Yeast cells of rather large size which, in an 

 old malt-agar culture, have produced hypha-like outgrowths of limited 

 growth in length. Drawn by A. H. R. Buller and Ruth Macrae. Magni- 

 fication, 2234. 



a large colony on malt-agar in a Petri dish and is shot upwards so 

 as to fall on to the agar close to the colony, it germinates on the 

 agar, but it and its progeny show evidence of being affected by the 

 exhaustion of the medium or by staling products ; for (a) it and 

 its progeny form only a relatively small colony of yeast cells before 

 the yeast cells begin to produce fresh spores, and (b) some or 



