SPOROBOLOMYCES 181 



many of the yeast cells, instead of retaining the oval or ellipsoid 

 form, become elongated like hyphae or variously irregular in 

 form (Fig. 88). Moreover, the sterigmata often become abnor- 

 mally elongated, two or more in number instead of one only, 

 and frequently bifurcated (Fig. 89). In very exhausted 

 media, presumably rich in staling substances, a spore, when 

 germinating, gives rise not to a yeast cell but to another spore 

 (Fig. 97, p. 193). 



The Production and Violent Discharge of the Spores.— The 

 normal method of spore-production and spore-discharge, which was 

 first observed by Kluyver and 

 van Niel, is illustrated in Fig. 90, 

 nos. 1-8. The sterigmata are pro- 

 duced by yeast cells only when the 

 cells are in contact with the air, 



and every Sterigma grows away Fig.89.— Sporobolomycesroseus. Yeast 



from the substratum into the air. g£ T^jTSSS^rSSS 



A sterigma, after beginning its A > Wlth two branched sterigmata, 



which presumably produced four 

 development, becomes fully formed spores in succession, one from 



in 30-50 minutes, at the end of Z$*$L£il2Z£L.'5& 



which time a spore begins to de- presumably produced three spores 



in succession, one from each point. 



Velop at its summit (Fig. 90, no. 3). Drawn by A. H. R. Buller and 



i, n , ,i • Ruth Macrae. Magnification, 



At first the spore is a minute 2 234. 



spherical body but, with further 



development, it becomes asymmetrically situated on the end of 

 the sterigma just as do the basidiospores of the Hymenomycetes, the 

 Uredineae, and Tilletia. The development of a spore from its first 

 rudimentary beginning to full size takes about 30 minutes (Fig. 90, 

 nos. 3-5). After full size has been attained, the spore remains on 

 its sterigma for 30-50 minutes and is then violently discharged. 

 Just before discharge, a drop of liquid appears at the hilum of the 

 spore and in 3-5 seconds its diameter increases until it is about 

 equal to that of the spore (Fig. 90, nos. 6 and 7). The spore and 

 the drop are then suddenly shot away together (Fig. 90, no. 8). 

 In one instance, when the sterigma was inclined away from the 

 vertical, the spore after being shot into the air settled on the surface 

 of the agar at a horizontal distance of 0-11 mm. from the parent 



