Chapter IX 

 THE ASPERGILLUS GLAUCUS GROUP 1 



Outstanding Characters 



Perithecia generally present; yellow, globose to subglobose, thin-walled, 

 suspended in networks of red or yellow hyphae. 

 Asci 8-spored, without definite arrangement; usually ripening in 2 to 



4 weeks. 

 Ascospores lenticular, smooth or rough-walled, generally showing an 

 equatorial line or furrow with or without flanking ridges or crests. 

 Conidial heads more or less abundant, radiate to somewhat columnar, 

 typically in some shade of green. 

 Conidiophores smooth-walled, terminating in dome-like vesicles. 

 Sterigmata in one series, rather coarse. 



Conidia elliptical to subglobose, uniformly and characteristically 

 roughened. 



General Considerations 



Aerial hyphae encrusted with yellow, orange, or red granules are abun- 

 dant in perithecial areas of most of the strains of the group. Both labora- 

 tory cultures and naturally moldy specimens frequently show this as their 

 most conspicuous character, one which is readily recognized with the hand 

 lens. In nature, molds of this group appear as patches of green, yellow, 

 reddish, or reddish-yellow mold, depending upon the relative abundance of 

 conidial heads, perithecia, and encrusted aerial hyphae, and especially 

 influenced by the composition of the substratum. 



Representatives of the A. glaucus group are universally distributed in 

 nature and are significant in the incipient spoilage of many organic ma- 

 terials useful to man. They occur particularly upon products characterized 

 by a high osmotic tension such as preserves, jams, cured meats, leather 

 goods, improperly dried hay, moist grain, and soft woods stored under 

 humid conditions. The classic habitat is improperly dried herbarium 

 specimens. 



The earliest references to any Aspergilli concern representatives of this 

 group, for botanists early encountered them upon herbarium material. 

 Micheli in 1729 used the generic name Aspergillus (rough head) for the 

 conidial heads, characterized by divergent chains of spores, commonly 

 present upon such specimens. Later in the century, Wiggers (1780) pro- 



1 Abridged from: Charles Thorn and Kenneth B. Raper, The Aspergillus Glaucus 

 Group, U. S. Dept. of Agr., Misc. Pub. No. 426, Washington, D. C, September 1941. 



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