Chapter XVIII 

 THE ASPERGILLUS WENTII GROUP 



Outstanding Characters 



Conidial heads large, typically globose, often splitting irregularly in 

 age — varying in color from dull yellowish to ecru-olive, and from light 

 to dark brown depending upon the species and strain. 



Conidiophores smooth-walled or nearly so, but often appearing finely 

 roughened when examined in dry mounts. 



Vesicles globose, fertile over the entire surface. Sterigmata in two 

 series. 



Conidia commonly elliptical, smooth or somewhat roughened depending 

 upon the species. 



Sclerotia present or lacking, dark brown to black, characteristically 

 white-tipped when young. 



The Aspergillus wentii group as presented here is recognized as somewhat 

 artificial, in comparison with such strictly natural groupings as the A. 

 glaucus, A. nidulans, and A. clavatus groups. The degree of relationship 

 between the species included is open to question. Yet all of the forms 

 possess certain characteristics in common: (1) conidiophores are smooth- 

 walled, or nearly so; (2) conidial heads are large and strictly globose, at 

 least when young; and (3) all appear to occupy taxonomic positions some- 

 what intermediate between the Aspergillus niger group on the one hand 

 and the Aspergillus flavus or Aspergillus ochraceus groups on the other. 



Group Key 



I. Conidia smooth-walled. 



A. Sclerotia lacking; vegetative mycelium and young conidiophores reddish in 



color. 



1. Conidial heads light brown, near wood brown (Ridgway PI. XL) 



A. panamensis Raper and Thorn 



B. Sclerotia present, dark brown to black, vegetative mycelium colorless, and 



young conidiophores colorless or pale yellow. 



1. Conidial heads dull yellow to ochraceous; sclerotia globose or nearly so 



A. alliaceus Thorn and Church 



2. Conidial heads in yellow-green shades near ecru-olive (Ridgway PL 



XXX) A. avenaceus G. Smith 



II. Conidia more or less echinulate. 



A. Sclerotia present or lacking, depending upon the strain and the substratum; 

 conidial areas in orange-brown to brown colors. 



1. Conidiophores colorless; colonies often conspicuously floccose 



A . wentii Wehmer 



2. Conidiophores brown (See A. niger) A. hennebergi Blochwitz 



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