ASYMMETRICA-DIVARICATA 273 



Sabet (1935) discussed the locales from which he isolated Penicillium 

 egyptiaciim and subsequently studied in some detail the cultural and mor- 

 phological characteristics (1936) and the nutritional requirements of this 

 fungus (1938). Cultures developed conidiophores in large nurtibers but 

 produced few perithecia in media containing one per cent NH4CI as a 

 source of nitrogen. Growth was arrested in media containing asparagine 

 and few perithecia were produced. The mold showed no significant differ- 

 ences in growth within a pH range of 3.8 to 8.8 but perithecia developed 

 later on the most alkaline media. 



Penicillium r.\istrickii Series 

 utsta tiding Clia meters 



Sclerotia characteristically produced, ranging from very hard, well or- 

 ganized structures in some forms to irregular, comparativel}' soft masses 

 of thick-walled pseudoparenchymatous cells in others. 



Colonies growing rather rapidly upon most substrata, in some members 

 developing abundant sclerotia which maj^ markedly influence the colony 

 appearance, in others producing sclerotia less abundantly and these 

 commonly obscured by an overgrowth of conidial heads and vegetative 

 mycelium. 



Conidial structures usuall}" abundant with conidiophores arising mostly 

 from the substratum to produce a velvety effect in heavilj^ sporing areas, 

 commonly up to 250 to 400m or more in length, with walls typically 

 roughened, often conspicuously so. 



Penicilli typically biverticillate and asymmetrical, commonly consisting of 

 terminal verticils of 3 to 5 metulae, usually somewhat divergent hence 

 suggesting clusters of separate monoverticillate penicilli under low 

 magnification. 



Conidia typically globose to subglobose, mostly 2.0 to 3.0m in diameter, 

 with walls generally smooth or nearly so. 



Series Key 



1. Conidial areas velvety or nearly so upon most substrata, conidiophores arising 

 from the substratum or from aerial hyphae P. raistrickii series 



a. Conidiophore walls coarsely roughened, sclerotia well organized, firm or stony. 

 1'. Sclerotia very hard, stony, white to light pink in color, vegetative mycelium 



white P- raistrickii Smith 



2'. Sclerotia fairly firm, not sclerotioid, yellow to light brown in color, vegeta- 

 tive mycelium often developing yellow shades from encrustment with 

 yellow granules P- pulvillorum Turfitt 



b. Conidiophore walls finely roughened, true sclerotia lacking but small rounded 



masses of thick-walled cells evident upon all substrata and particularly upon 

 malt agar P- sop-pi Zaleski 



