THE ASPERGILLUS FLAVIPES GROUP 181 



8 to 10/x in diameter in some strains and under some conditions of culture, 

 walls more or less yellow under the microscope, with color mostly localized in 

 the outer layers of the cell-wall and occasionally as disk-like concretions 

 on the surface of walls otherwise smooth. Vesicles subglobose to elliptical 

 (fig. 51 D), up to 30 by 4G> in the largest forms, usually with diameter 

 twice that of the conidiophore in smaller forms. Sterigmata in two series, 

 colorless or nearly so, closely packed over the apex of the vesicle in small 

 heads, and covering the vesicle in large heads, primary sterigmata about 

 6 or 8m by 2 to 3/x, secondary sterigmata 5 to 8/x by 1.5 to 2/x. Conidia 2 

 to 3ju, smooth, subglobose, colorless or nearly so under high magnification, 

 with chains aggregated to form columns as seen with the handlens in old 

 cultures. 



Cosmopolitan in distribution and particularly common in soil and upon 

 decomposing organic materials. 



Historically, the name applied to the series is taken from strains 4640.474 

 and 4640.402 (Thorn Collection) obtained through daFonseca from the 

 Bainier collection in Paris in 1922. These strains showed smooth yellow 

 con idiophores 300 to 400m by 3 to 4ju, contrasting with heads that were 

 rath er persistently white and possessed the general morphology of the series 

 as described above. Hulle cells were not found. Nevertheless, the close 

 relationship of these organisms to a great series of cultures obtained from 

 many sources in which these structures are regularly found justifies us in 

 broadening the use of the name. 



Culture No. 4640.486 (Thorn) received from the Bainier collection as 

 S. rubescens (XRRL No. 291) shows deep floccose colonies with few heads 

 and scattered dark Ivyphal masses in age. Hulle cells have not been seen in 

 this strain. 



Among forms commonly obtained from soils collected from widely 

 scattered areas in this country and abroad, a series of isolates seems to 

 comply with the description given by Blochwitz for Aspergillus archi- 

 flavipes (Ann. Mycol. 32(1/2): 84. 1934). This species as described 

 represents an extreme development toward radiate heads, abundant conidia, 

 conidiophores 2 to 3 mm. in length and the development of deep brown or 

 actual red shades of color in the mycelium. Several strains observed in 

 culture approach this description (fig. 51 C). Heads are at first globose, 

 then become slowly barrel-form, i.e., short stocky columns. Large brown 

 drops of transpired fluid are commonly seen which become yellow when 

 acidified and return to reddish shades when alkali is added. Recognition 

 of the species does not appear warranted since no clearly definable character 

 exists which distinguishes these isolates from the less colored forms generally 

 considered as representing Aspergillus flavipes in a more restricted sense. 



