OBSERVATION AND DESCRIPTION OF PENICILLIA 



37 



may be quite misleading. Biourge, for example, proposed the name P. 

 pezizoides for a member of the Fasciculata approximating P. piibendum 

 Bainier in which the droplets upon evaporation left conspicuous peziza- 

 like craters, pink in color. Another disturbing factor introduced by these 

 drops is the not infrequent germination of conidia followed by secondary' 

 growth in the transpired fluid. When this occurs it often results in the 

 formation of globose mycelial masses upon the surface of the colony which 

 may erroneously be interpreted as fasciculate in origin and structure. 



ODOR 



Characteristic pungent or penetrating odors are produced by many 

 species of Penicillium. Usually these are referred to as "moldy" or 



Fig. 6. Exudate formation in Penicillium notatum Westling. A, Colony showing 

 abundant exudate, or drops, X 2. B. Enlarged area of the same, X 15. 



"musty," but such nomenclature is very unsatisfactory due to the vaiying 

 response of different individuals when confronted with the same prepara- 

 tion. Due to this variability, one is often unable to interpret terms 

 previously used or to insure an understanding of the terms being proposed. 

 Odors have some apparent taxonomic significance in a limited number of 

 cases. Among the Fasciculata, wherever odors are produced, these are 

 usually diagnosed as "moldy" and vary from slight to very intense 

 in certain cases such as Penicillium daviforme and P. olivino-viride. 

 Among the biverticillately symmetrical forms, species assignable to the 

 P. purpurogenum series are usually characterized by a fragrant apple, or 

 in age a walnut-like, odor which is particularly marked upon malt agar. 

 Penicillium digitaium in laboratory culture produces a characteristic 

 odor variously described as that of spoiling citrus fruit or unpickled dill, 



