THE SAC FUNGI (ASCOMYCETES) 



231 



O, 



The heavy-walled ascocarp is resistant to unfavorable cli- 

 matic conditions, and may pass through the winter and in the 

 following spring break open, thus freeing the thin-walled asci. 

 Upon escaping, the spores may be blown or carried about and 

 germinate upon new host leaves. 



224. Blue mold or green mold (Penicillium). This mold fre- 

 quently appears upon discarded leather, upon shoes or gloves 

 which when damp have been left in a 

 dark warm place, upon old lemons, and 

 upon cheese and other dairy products. 

 Various species have distinct shades 

 of color, so that the common names of 

 blue or green mold can be taken only 

 as applying in a general way. Certain 

 species of Penicillium are supposed to 

 give characteristic flavors to cheese 

 in which they grow, as Penicillium 

 Roqueforti of Roquefort cheese and 

 Penicillium Camemberti of Camembert 

 cheese. These species are widely dis- 

 tributed, however, and are found 

 growing upon many substances other 

 than cheese. It has been suggested 

 that these are not different species, 

 but that they merely show different 

 features, dependent upon the kind 

 of material upon which they grow. 

 While it is true that these as well as species of other molds do 

 show different characteristics when grown in different ways, 

 recent investigations indicate that the species are distinct. 1 



Penicillium is an ascomycete which has almost lost the 

 habit of reproduction by means of ascospores, the ascus being 



1 An interesting discussion of various species and their cultural reac- 

 tions is " Cultural Studies of Species of Penicillium," by Charles Thorn, 

 Ph.D., Mycologist in Cheese Investigations, Bulletin 148, Bureau of Animal 

 Industry, U. S. Dept. Agr., 1910. 



FIG. 187. The blue mold 

 (Penicillium) 



At the left is the tip of a hy- 

 pha, with the characteristic 

 branches, on the ends of which 

 are the spores; at the right 

 are germinating spores. After 

 Thorn. Much magnified 



