Chapter X 

 THE ASPERGILLUS FUMIGATUS GROUP 



Outstanding Characters 



Conidial heads columnar, in shades of green through dark green to 



fuliginous. 

 Vesicles flask-shaped, typically fertile over the upper half. 

 Sterigmata in one series, crowded. 



Conidiophores smooth-walled, usually colored in shades of green. 

 Conidia globose, echinulate, green. 



Working with lung material from birds dying oi aspergillosis. Presenilis, 

 about 1850, described and figured the species Aspergillus fumigatus to well 

 that there has never been any doubt as to the morphology of the mold 

 present. The investigator of molds in culture, however, quickly finds that 

 this type of conidiophore and head characterizes not a single pathogenic 

 strain but a multitude of variant forms that are abundant in soil, upon 

 decaying vegetation, and. in fact, wherever organic materials are under- 

 going even the slightest aerobic decomposition. To all oi these forms, col- 

 lectively, the designation Aspergillus fumigatus group is applied. . 



The group falls naturally into two series: 



Cultures strictly conidial, varying from velvety to floccose I. fumigatus series 



Cultures producing perithecia and ascospores, conidial development generally 

 limited A. fischeri series 



THE ASPERGILLUS FUMIGATUS SERIES 



Aspergillus fumigatus Presenilis, in Beitrage sur Mykologie. p. 81, pi. 10, 



tigs. 1-11. Frankfurt, 1850 53. Thorn and Church. 



The Aspergilli. p. 120. 1926. 



Colonies upon Czapek's solution agar spreading broadly over the sub- 

 stratum, in some strains strictly velvety (PI. IV B and fig. 37 A.), in others 

 more or less floccose with varying amounts of tufted-aerial mycelium to deep 

 felted or extremely floccose forms (fig. 37 B), white at first, becoming green 

 with the development of heads but varying considerably in the final shade of 

 green, often becoming dark green to almost black in age. Reverse and 

 substratum, in some strains uneolored. in others showing varying amounts 

 of yellow, or again passing over in dark red shades in age. Conidial heads 

 columnar, compact, varying in measurement from strain to strain up to 400 

 by 50m, hut usually much shorter, occasionally very small. Conidiophores 



14> 



