NADSONIA ELONGATA 



223 



son and Konokotine) . 



1-3, Germination of Spores; 4, Ascs; 5, Cycle. 



The asc is derived from a heterogamic copulation of two cells. The 

 female cell or macrogamete is an adult cell and the male cell or 

 microgamete is a small bud formed by the macrogamete. Both cells 

 or gametes become united by means of a copulation canal. The con- 

 tents of the microgamete enter the macrogamete from which an egg 

 results. This then changes into 

 an asc. The asc contains a 

 single ascospore. The spore is 

 spherical with a large globule 

 of fat in its center. Its mem- 

 brane is rough with little ele- 

 vations and has a reddish brown 

 color. On account of this color, 

 it is easy to recognize macro 

 scopically a culture which has 

 sporulated. During germination 



the spore swells up and breaks Fig. 91-B. Nadsonia fulvescens (after Nad- 

 open the wall. Liberated, it 

 develops a germinating tube 

 and produces a vegetative cell. This yeast has both sporogenic 

 and asporogenic types. The asporogenic type develops into colonies 

 (giant) which are distinguished by their white color from those of 

 the sporogenic which are reddish brown. This species ferments 

 dextrose, galactose, levulose and saccharose slowly. 



NADSONIA ELONGATA. Konokotin 



This yeast possesses vegetative cells 

 which are oval or elongated. Copulation 

 is accomplished as in Nadsonia fulvescens. 

 The asc results from an egg containing 

 a single spore. These ascospores have a 

 very verrucose membrane and germinate 

 by ordinary budding. The giant colonies 

 on peptone gelatin with 5 per cent of 

 glucose are rosette-shaped. They have 

 brown centers and white peripheries. 



This species ferments dextrose and levu- 

 Fig. 91-C. Nadsonia elongata 



(after Konokotine). lose, but has no action on other sugars. 



Genus V. Schwanniomyces. Klocker 



Ascs derived from cells which have preserved a trace of sexual 

 attraction. Ascospore provided with a single membrane on the sur- 



