BIVERTICILLATA-SYMMETRICA 



587 



face growth comparatively loose, almost floccose, in flesh to orange-pink 

 shades, tardily developing conidial structures in limited numbers; rarely 

 producing perithecia (see malt agar) ; odor not pronounced ; exudate limited 

 or lacking; reverse at first colorless, developing red shades in age; penicilli 

 variable in pattern, mostly fractional, commonly monoverticillate, some- 



FiG. 150. PenicilUum helicum Raper and Fennell, NRRL 2106. A and B, Ten- 

 day-old colonies on Czapek and malt agars. C, Mature perithecia as seen on corn 

 meal agar, X 30. D, Mature ascospores showing characteristic elliptical form, but 

 failing to show delicate-echinulation, X 1500. 



times branched and usually asymmetric, sometimes biverticillately-sym- 

 metrical in the manner characteristic of the series; conidiophores borne 

 primarily as branches from aerial hyphae, commonly 100m or less in length 

 by 2.0 to 2.5m, '^vith walls smooth or irregularly roughened and colored in 

 light yellow-green shades; metulae variable, when present commonly 10 to 

 15m by about 2.0m, rarely occurring in clusters of more than 3 or 4; sterig- 



