THE ASPERGILLUS USTUS GROUP 175 



common forms only in its more floccose habits and in the production of 

 somewhat smaller conidial heads. 



Among the more striking members of the Aspergillus ustus series 

 examined are two isolations from soil collected in Panama and Mexico, 

 respectively, which upon Czapek's solution agar normally produce strongly 

 zonate colonies consisting of alternating areas of crowded conidial heads 

 and heavy hiiHe cell development (fig. 48 D). Except for this difference in 

 colony appearance, however, these strains appear to be typical of the species 

 as described above. 



A single strain, NRRL No. 1852, isolated from Louisiana soil, possesses 

 conidial heads of a dull brick red color (Ridgway, PI. XXXIX: russet 

 vinaceous to sorghum brown) and abundant, much-twisted hulle cells. 

 While Blochwitz's description is too inadequate to permit of detailed com- 

 parison, it is suggested that this strain may represent his Aspergillus ustus 

 var. laevis (Ann. Mycol. 32(1/2): 4. 1934), which was described as 

 characterized by "red conidia and crooked hiiHe cells." In strain NRRL 

 No. 1852, the conidia are conspicuously reddish en masse but appear only 

 slightly colored when viewed with high magnifications. In contrast to 

 most strains of the Aspergillus ustus group, the conidia are finely echinulate 

 rather than coarsely roughened. It is suggested that this form (fig. 48 C) 

 may represent a transition in the direction of Aspergillus flavipes since the 

 latter species is likewise characterized by much-twisted hiiHe cells, brown 

 conidiophore walls, and conidia which may show a reddish color in some 

 strains but are smooth in all. 



Aspergillus granulosus Raper and Thorn, in Mycologia 36: 565-568, 



fig. 4. 1944. 



Colonies upon Czapek's solution agar growing well, attaining a diameter 

 of 8 to 10 cm. in two to three weeks at room temperature, plane or irregu- 

 larly furrowed, predominantly floccose, uneven in texture, buff to dull brown 

 in color from felted sterile mycelia ; conidial heads few in number and gen- 

 erally arising from the substratum direct, less often from aerial hyphae, 

 commonly appearing in clusters, pale blue-green in color; colonies charac- 

 terized particularly by abundant small, colorless clusters of irregularly 

 globose, ovoid, or elliptical thick-walled hiiHe cells which superficially sug- 

 gest perithecial initials and which in mass give to the colony a semi-granular 

 appearance (fig. 50 B, E, and F); reverse in shades of dull yellow and 

 brown; slight mushroom odor. Conidial heads few in number, commonly 

 clustered in small groups, most abundant at colony margin, sometimes 

 occurring on tufts of aerial hyphae, hemispherical to radiate, 75 to 125/x 

 in diameter, very loose, consisting of comparatively few divergent spore 

 chains (fig. 50 C), approximately pale niagara green in color (Ridgway, 

 PI. XXXIII). Conidiophores erect, straight, nonseptate, mostly 350 to 



