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A MANUAL OF THE ASPERGILLI 



color and appearance (PI. VII F and fig. 75 A) ; reverse ranges from colorless 

 through orange to purplish shades. 



Conidial heads when large mostly globose or variously splitting into 

 masses of conidial chains (fig. 75 C), variously colored from very pale to 

 deep ochraceous shades . Conidiophores vary greatly in length and diameter 



Fig. 75. Aspergillus ochraceus series. A and B, A. ochraceus, NRRL No. 398 

 and No. 408, respectively, growing on Czapek's solution agar at room temperature, 

 10 days. C, Mature heads of strain No. 398; the tendency to split into divergent 

 columns in age is characteristic. D, Photomicrograph of a single head showing globose 

 vesicle, sterigmata in two series, and coarsely roughened conidiophore, X 325. 



in the various strains, but typically show a yellow color in the outer layers 

 of the thick wall which shows characteristic pitting or roughening (fig. 

 75 D). Vesicles mostly globose or somewhat elliptical, and fertile over the 

 whole surface (fig. 75 D). Sterigmata in two series: primary varying from 

 small to very large, commonly 15 to 30/x in length; secondary fairly uniform, 



