168 A MANUAL OF THE ASPERGILLI 



empire green (Ridgway, PI. XXXII), generally hemispherical to loosely 

 columnar, mostly 75 to 125m in diameter. Conidiophores straight or 

 slightly sinuous (fig. 45 D), mostly 250 to 325m in length, occasionally up 

 to 350m by 5.0 to 6.5m in diameter, of approximately uniform diameter 

 throughout, relatively thick-walled, (1.2 to 1.5m in basal portion to 0.8 

 to 1.0m in terminal area), smooth, tan to light brown in color. Vesicle 

 slightly elongate, the upper hemisphere loosely covered by sterigmata 

 (fig. 45 D), the lower half sterile and often lightly colored, mostly 15 to 20m 

 in diameter. Sterigmata in two series (fig. 45 D), primaries normally 6.5 

 to 8.5m by 3.5 to 5.0m, secondaries 6.5 to 8.0m by 3.0 to 4.5m, typically bottle 

 form but commonly much swollen and often quite irregular in form and 

 dimensions. Conidia globose, spinulose, green, mostly 3.5 to 4.5m, rarely 

 larger, hiiHe cells very abundant, thick-walled, irregularly globose, ovoid or 

 elliptical (fig. 45 E), ranging from 12 to 18m in globose cells to 12 to 15m 

 by 25 to 30m in the most elongate bodies, forming compacted masses of 

 indefinite size, extremely tough and in age becoming almost sclerotioid, at 

 first colorless but in age characterized by an abundant reddish-purple 

 intercellular pigmentation. 



Colonies upon malt agar characterized by a dense stand of erect conidio- 

 phores bearing hemispherical to radiate or loosely columnar heads of dark 

 green color approximately empire green (Ridgway, PL XXXII) and the 

 complete absence of hulle cells; reverse in light brown shades; odor none. 

 Details of morphology as upon Czapek's solution agar. 



Colonies upon hay infusion agar like those upon malt except less heavily 

 sporing. 



Strains include NRRL No. 1929 (type) isolated from Arkansas soil and 

 other isolations from Arizona and Texas soils. 



This species is of particular interest because of its apparent transitional 

 position between the A. nidulans group and A. ustus. In the character 

 of its conidiophores, its reddish-purple pigmentation, and in the general 

 color and markings of its conidia it retains the characters of A. nidulans 

 and closely related species. In the absence of fertile perithecia and asco- 

 spores, the predominantly hemispherical shape of its conidial heads, and in 

 the variable and irregular form of its hiiHe cells, it is strongly suggestive of 

 the A. ustus series. While we are convinced of its. intermediate position 

 between the A. nidulans group and A. ustus, we place it with the former 

 since we believe it is most closely allied to this group. It is believed sig- 

 nificant that superficially, cultures of Aspergillus caespitosus and Aspergillus 

 variecolor (Berk, and Br.) Thorn and Raper (1939) are strikingly similar 

 upon Czapek's solution agar. This similarity is particularly marked when 

 plates are viewed in reverse since an intense pigmentation marks the under 

 surface of perithecia in the latter case and the under surface of older hulle 

 masses in the former. 



