MONOVERTICILLATA 163 



pigmented substance appearing almost crystalline. As reported by van 

 Beyma the pigment is readily soluble in alcohol, ether, and other solvents, 

 but insoluble in water. Van Beyma recorded sclerotia as somewhat larger 

 (500 to 700^) than observed in our cultures and reported that they were 

 produced more abundantly at temperatures of 25 to 26 °C. than at tempera- 

 tures below 20°C. 



The species differs from Penicillium thomii Maire primarily in the pro- 

 duction of abundant bright red mycelia accompanying the sclerotia, and 

 in producing conidiophores with walls smooth or nearly so on Czapek's 

 solution agar, although delicately roughened on malt agar. It is closely 

 related to P. thomii. 



Penicillium lapidosum Raper and Fennell, in Mycologia 40 : 524-527, 



fig. 6. 1948; also Wilhams, Cameron, and Williams in Food 



Research 6: 69-73. 1940. 



Colonies on Czapek's solution agar spreading broadly, attaining a diam- 

 eter of 5.0 to 6.0 cm. within 2 weeks at room temperature, plane or hghtly 

 furrowed (fig. 46A), golden orange in color, developing reddish tints in age, 

 consisting of an extensive vegetative mycelium largely submerged, de- 

 veloping abundant orange-bro^^^l sclerotia in a fairly dense layer on the 

 agar surface, \\dth hmited development of sterile aerial hyphae often more 

 or less obscuring the individual sclerotia; penicilli rarely produced and not 

 affecting the colony appearance (see description on hay agar below) ; exu- 

 date abundant, in orange-red shades ; odor lacking or indistinct ; reverse in 

 orange-red shades becoming deep reddish bro^\^l in age; sclerotia globose 

 to subglobose, variable in size up to 300 to 350m in diameter (fig. 46C), very 

 hard, crushing with difficulty, composed of very thick-walled polygonal 

 cells mostly 10 to 15ju in diameter. 



Colonies on steep agar as on Czapek but gromng even more rapidly and 

 generally producing more abundant exudate and more intense coloration 

 in reverse; penicilli very sparsely produced; sclerotia as above. 



Colonies on malt agar spreading broadly, plane (fig. 46B), quickly de- 

 veloping golden yellow shades from abundant orange colored sclerotia and 

 enveloping yellow encrusted sterile hyphae; exudate abundant, clear; peni- 

 cilU developing fairly abundantly in older colony areas but not affecting the 

 overall appearance of the culture. 



Colonies on hay infusion agar growing rapidly, thin, consisting of a 

 spreading, submerged vegetative mycelium, producing sclerotia in limited 

 numbers in a thin layer on the agar surface with these surrounded by and 

 overgro^^^l with a thin network of interwoven and trailing vegetative hy- 

 phae bearing numerous penicilH on short lateral branches or conidiophores; 

 sclerotia as described above but generally smaller, rarely exceeding 200/i in 



