242 A MANUAL OF THE ASPERGILLI 



Aspergillus panamensis Raper and Thorn, in Mycologia 36: 568-572, 



fig. 5. 1944. 



Colonies on Czapek's solution agar at room temperature very thin, 

 consisting of a sparse and transparent growth of vegetative hyphae, almost 

 wholly submerged, bearing widely scattered, erect conidial structures 

 with radiate heads, light brown in color. Colonies upon malt extract agar 

 at room temperature growing well and fruiting luxuriantly, reddish brown 

 in color, consisting of a dense basal mycelium, predominantly red, from which 

 develop massed condial structures in broken or continuous concentric 

 zones (fig. 65 A), many conidiophores abortive and sterile, fertile co- 

 nidiophores bearing globose to radiate heads, light brown in color, near wood 

 brown (Ridgway, PI. XL) ; these, together with red-colored sterile structures 

 and aerial hyphae, give the colony its characteristic appearance and color; 

 in age, colonies tending to develop a loose floccose overgrowth, more or 

 less obscuring the abundant conidial heads; reverse dull brown; odor none. 



Conidial structures arising directly from the substratum, scattered or 

 abundant, depending upon the culture medium employed (fig. 65 B). 

 Heads typically globose, in age characterized by loosely radiating chains 

 of conidia, less commonly by few to several roughly columnar masses variable 

 in size, commonly ranging from 250 to 450m in diameter, occasionally up 

 to 500m, varying in color from avellaneous to wood brown (Ridgway, PL XL) 

 to Saccardo's umber (Ridgway, PI. XXIX). Conidiophores straight, 

 mostly 600 to 900m in length by 9 to 12m in diameter, occasionally larger, 

 with walls smooth, comparatively heavy, ranging from 3 to 3.5m thick in 

 the basal area to 1.5 to 2m in the terminal area, approximately uniform in 

 diameter throughout except for a limited reduction immediately beneath 

 the vesicle. Vesicle colorless, comparatively thin-walled, globose or 

 slightly elongate, mostly 25 to 30m in diameter, fertile over the entire area 

 (fig. 65 C). Sterigmata in two series, closely packed, primaries 5.5. to 

 6.5m by 2.4 to 2.8m, secondaries 5 to 6m by 1.5 to 2m. Conidia light yellowish- 

 brown in mass, globose to subglobose, smooth-wal'ed, mostly 2.2 to 2.6m 

 in diameter, occasionally 2.8m- 



Type culture NRRL No. 1785 was isolated in January 1942, from 

 Panama soil collected by Mr. John T. Bonner. A second culture, NRRL 

 No. 1786, differs from the above strain in minor details but clearly belongs 

 with it. This was isolated from a second sample of Panama soil collected 

 by Bonner. 



The species is considered to represent a form somewhat intermediate 

 between the Aspergillus nigcr group and A. wentii. Superficially, at 

 least, there is evidence of relationship with Aspergillus niger mut. cin- 

 namomeus (syn. Aspergillus cinnamomeus Schiemann) and Aspergillus 

 niger mut. Schiemanni (syn. A. fuscus Schiemann). It bears a certain 



