THE GENERA PICHIA AND WILLIA. 287 



tSaccharomycopsis capsularis, SCHIONNING (II.) has been drawn 

 by this worker. The cells are sometimes ovoid, sometimes 

 sausage-shaped ; and typical septated mycelia are also observed. 

 The limits of budding temperature in wort are 38.5 C. and 

 about 0.5 C., the optimum being 25-28 0. On nutrient liquids 

 the species quickly forms a decidedly white, irregular, shaggy 

 film ; but on solid media it develops into a more or less irregular, 

 white, shaggy vegetation, which turns chocolate-brown in old 

 cultures on wort-gelatin agar-agar. The spores are generally of 

 oblate spheroidal form, with a maximum diameter of 3.5-8/4, and 

 usually 4 in a cell. The limits of sporu'ation temperature on 

 gypsum blocks are 34-5 -35 C. and 5-8 C., the optimum being 

 25-28 C. In germination, the exosporium opens in the form 

 of two valves, generally of unequal size, and often remaining for 

 some time attached together at one point and adhering to the 

 germinating spore. The exosporium is stained pink by con- 

 centrated sulphuric acid and several other concentrated mineral 

 acids. The species thrives in wort, yeast water, on wort gelatin, 

 wort-gelatin agar-agar, yeast- water gelatin, rice, and bread. It 

 ferments dextrose, laavulose and maltose, but not saccharose, 

 lactose and raffinose. It was discovered in the soil of a meadow 

 in the Swiss Alps. 



280. The Genera Pichia and Willia. The doubtful 

 Genera Monospora and Nematospora. 



The two main groups of the true Saccharomycetacece (p. 273, 

 vol. ii.), comprise the genera Pichia and Willia, the species of which 

 produce a film on saccharine nutrient liquids immediately. The 

 film has a dry, dull appearance, due to the inclusion of air bubbles, 

 and exhibit well-defined differences from that produced by the 

 genera described in 278 and 279. The spores are of various 

 shapes, with or without a projecting ledge, and have only a single 

 membrane. Several of the species are characterised by the 

 formation of esters, and a few of them do not excite fermentation. 



In the genus Pichia, E. C. HANSEN (XLIX.), the spores are 

 rounded, hemispherical, or irregular and angular. No fermenta- 

 tion is produced. A strong mycelium is formed. The following 

 eight species (inter alia} of this genus are known : 



Pichia membranwfaciens, E. C. Ilansen. Synonyms : Saccha- 

 romyces membranwfaciens, E. C. HANSEN (XLVI. and XLVIII.) = 

 Pichia niembrancefaciensy E. C. HANSEN (XLIX ). The species 

 has been drawn by SEIFERT (II.). The film cons ; sts of sausage- 

 shaped and elongated oval cells, rich in vacuoles. Limits of 

 budding temperature on wort, 35-36 C. and 6.5 C. The 

 colonies on wort gelatin are dull grey, often with a reddish tinge, 

 and the medium is liquefied very quickly. The spores are 

 rounded or hemispherical, and are produced in large numbers 

 VOL. ii : FT. 2 T 



