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A MANUAL OF THE PENICILLIA 



and showing prominent echinulations or winding color bars which may- 

 become detached when mounted in alcohol and mounting fluid.^ 



Colonies on steep agar about 4.0 to 4.5 cm. in diameter in 12 to 14 days, 

 predominantly velvety, radiately wrinkled (fig. SOB), quickly becoming 



Fig. 50. PcniciUium purpurrescens (Sopp) n. comb., NRRL 720. A and B, Two- 

 week-old colonies on Czapek and steep agars. C, Low-power view of colony margin, 

 X 40. D, Detail of penicilli, X 900; note echinulate globose conidia. 



dull in color, approximately mouse to olive gray to dark olive gray in age 

 (R., PI. LI), more or less zonate; exudate limited in amount; reverse as on 



2 A similar phenomenon was reported for certain members of the Aspergillus niger 

 group by Thorn and Church (1926) and was regarded by Thom as probably constitut- 

 ing the principal basis of Lutz's smooth -walled species, A. luteo-niger (1907). 



