20 



A MANUAL OF THE ASPERGILLI 



Fig. 4. Conidial heads; group types. A, Aspergillus clavatus group: conidial 

 heads of A. giganteus, NRRL No. 10, showing typical clavate form, X 15. B, Asper- 

 gillus glaucus group: heads of A. niveo-glaucus, NRRL No. 127, showing character- 

 istic radiate pattern, X 35. C, Aspergillus nidulans group: heads of A. nidulans 

 showing typical short-columnar form, X 35 (Photograph by Edward Yuill). D, 

 Aspergillus flavipes group: heads of A. flavipes, NRRL No. 1959, typically barrel- 

 form, or loose columnar as shown, X 18. E, Aspergillus terreus group: A. terreus, 

 NRRL No. 265, heads columnar, of uniform diameter throughout, often becoming 

 quite long as shown, X 22. F, Aspergillus ustus group: A. ustus, NRRL No. 1974, 

 heads typically loose and radiate as shown, under certain conditions approaching 

 columnar, X 22. 



