Fig. 9. Influence of substratum. A-C, Aspergillus variecolor, NRRL No. 212, 

 growing upon Czapek's solution, malt extract, and hay infusion agars, respectively; 

 10 days; room temperature. Note particularly the heavy development of perithecia 

 upon malt and the very sparse development of the same upon hay infusion agar. 

 D-F , Aspergillus caespitosus, NRRL No. 1929, growing upon the same media under 

 similar conditions. Upon Czapek's solution agar (D) dark hiille cell masses develop 

 along with a limited development of conidial structures; upon malt (E) and hay 

 infusion (F) agars hiille cell masses are lacking and conidial structures are very 

 abundant. 



36 



