504 A MANUAL OF THE PENICILLIA 



to 1 mm. or more deep, in other strains thinner and usually showing numer- 

 ous radial lines which first appear as furrows but subsequently develop as 

 ridges due to secondary growth, zonate with margins white, shading from 

 celandine green to lily green (Ridgway, PI. XLVII) or deep bluish gray- 

 green (R., PL XLII) in areas of mature penicilli; odor strong, "moldy"; 

 exudate limited, colorless to very pale yellow; reverse in orange-red shades 

 with surrounding agar becoming similarly colored, sometimes as a con- 

 spicuous halo 1 to 2 cm. beyond the colony margin; sporulating abundantly 

 with conidiophores arising from the substratiun or as branches from aerial 

 hyphae, commonly 200 to 300/x by 3.0 to 3.5ju, occasionally longer, with 

 walls finely roughened, bearing conidial structures of intermediate size 

 characterized by tangled conidial chains; penicilli biverticillate and asym- 

 metric (fig. 128F), irregularly branched with metulae and sterigmata 

 commonly borne at different levels; branches variable in size, commonly 

 10 to ISju by 2.5 to 3.0 n, occasionally longer; metulae usually in clusters 

 of 2 to 4, commonly 10 to 12/i by 2.5 to 3.0m; sterigmata usually 6.5 to 8.0m 

 by 2.0 to 2.5m, sometimes longer with abnormal cells occasionally observed, 

 tending to become detached in mounts of older structures; conidia elHptical 

 to subglobose, commonly measuring 3.0 to 3.5 or even 4.0m in long axis, 

 smooth-walled. 



Colonies on steep agar grow more rapidly and are more closely and 

 conspicuously ridged than on Czapek, about 3.5 to 4.0 cm. in diameter in 

 10 days at room temperature, lanose to tufted-fasciculate, 1.0 to 1.5 mm. 

 deep, heavily sporulating; exudate limited, colorless, largely embedded in 

 the mycelium; colony reverse in dull orange to maroon shades with agar 

 similarly colored in surrounding zones up to 1 to 2 cm. in width; penicilli 

 generallj^ larger with branches longer and more niunerous than on Czapek, 

 but otherwise similar. 



Colonies on malt agar about 3.0 to 3.5 cm. in diameter in 10 to 12 days, 

 consisting of a basal felt bearing a loose, floccose surface growth ranging 

 from thin in the marginal area to 1 to 2 mm. deep in colony centers, pale 

 yellow^ in color and usually non-sporulating (fig. 128E); no exudate; re- 

 verse in orange shades with surrounding agar colored in bay shades, some- 

 times to a distance of 2 cm. 



The species is represented by NRRL 2138 received from George Smith, 

 London School of Hygiene and Tropical Medicine in June 1947 as a sub- 

 culture derived from the original type. NRRL 2010 and NRRL 881, 

 obtained from the Centraalbureau and from the Thom Collection respec- 

 tively as Biourge's Perncillium aurantio-virens, are also representative of 

 the species, but differ from the above in being more nearly velvety and, 

 therefore, less typical of the group to which the species is assigned. NRRL 

 2029, isolated at this Laboratory from spoiled starch paste supplied by 



