ASYMMETRICA-VELUTINA 



351 



generally heavier sporing and in somewhat darker shades, similar in texture 

 and basic pattern except for more prominent radial furrows, commonly more 

 or less zonate; exudate and colony reverse as on Czapek; penicilli as de- 

 scribed above. 



Colonies on malt extract agar comparatively thin, plane, strictly velvety 



4 



\cmmmmKBtm .d 



Fig. 93. Penicillium steckii Zaleski. A and B, Tvvo-week^old colonies of NRRL 

 2141 on Czapek and malt agars. C, Low-power view of colony margin in NRRL 2140, 

 X 100. D, Detail of penicillus in latter strain, X 750. 



(fig. 93B), at first azonate but commonly narrowly zonate in marginal areas 

 after 2 to 3 weeks; exudate lacking; reverse uncolored or nearly so; penicilli 

 as described above. 



Species description centered upon NRRL 2140, from Professor Wm. H. 

 Weston as an isolate from a sample of fabric exposed on Barro Colorado 

 Island, Panama; NRRL 2141, from a second sample similarly exposed; and 

 numerous other strains isolated from many different soils and from various 



