MONOVERTICILLATA 



181 



occasional branch; sterigmata comparatively few in the verticil, about 6 

 to 10, measuring mostly 6 to 9m by 2.2 to 3.3m (fig- 51D); conidia sub- 

 globose to globose, rarely somewhat eUiptical, mostly 3.0 to 3.5m in di- 

 ameter, definitely roughened, spinulose, or in some strains showing winding 

 color bars. 



'>Mk 



B 



Fig. 51. Penicillium spinulosurn Thorn, NRRL 17E0. A and B, Two-week-old 

 colonies on Czapek and steep agars. C, Low-power views of colony surface showing 

 penicilli commonly borne from aerial hyphae, X 40. D, Detail of penicilli, X 900; 

 note spinulose character of conidial w^alls. 



Colonies on steep agar growing more rapidly, about 6.0 to 6.5 cm. in 

 diameter in 12 to 14 days, with mycelial felt somewhat heavier and more 

 floccose, generally heavier sporing but in the colors listed above (fig. 

 51B); reverse in dull gray or drab shades; penicilli as on Czapek except 

 sterigmata more numerous in the verticil ; conidia as on Czapek but show- 

 ing less irregularity in size. 



