CHAPTER LXII. 

 THE MONILLE AND OIDIA. 



BY DR. H. WICHMANN, 



Deputy Manager of the Austrian Research Station 

 and Academy of Brewing, Vienna. 



314. Monilia, Sachsia and Chalara. 



AMONG the organisms now classed as fungi imperfecti (p. 26, vol. ii.), 

 the species assigned to Monilia have a particular interest for the 

 fermentation technologist, the species in question forming a con- 

 necting-link, morphologically speaking, between the mould fungi 

 and the budding fungi. 



The members of the genus Monilia lack, in the first place, the 

 complete mycelium exhibited by the mould fungi, e.g., Penicil- 

 lium ; and, though divergent and branched hyphae are by no 

 means uncommon, the structure of the mycelium is very loose. 

 For this reason the films produced by certain of the species when 

 grown on liquid media are easily disintegrated, and exhibit a 

 greater resemblance to mould films. On the other hand, the bud 

 mycelia, the usual form of growth in this genus, show a more 

 extensive polymorphism than is ever found among the true 

 budding fungi ; and it is this peculiarity that forms the charac- 

 teristic feature of the genus. The bud mycelium, especially when 

 aged, mostly exhibits all the forms observed in budding fungi 

 from globular cells, resembling Torula, to elongated cells like 

 those of Mi/coderma, and even tubular cells of remarkable length, 

 these being interspersed by cells analogous to those of Oidium 

 and radial hyphre of typical structure. These mycelia, in addition 

 to appearing in nutrient liquids, constitute the normal form of 

 growth on solid, moist substrata, so that, e.g., the giant colonies 

 on wort gelatin resemble yeast rather than moulds. Another 

 regular phenomenon is that the vegetations of one and the same 

 species on different nutrient media exhibit such a great diver- 

 gence of cell form that no one would attribute them to the same 

 species. 



Another feature equally of diagnostic value is the absence of 

 characteristic organs of fructification. In most species it is 



443 



