ASYMMETRICA-VELUTINA 383 



uniformly sage green (R., PL XLVII) to Russian green (R., PL XLII), 

 with reverse at first uncolored becoming darker in age, characterized by a 

 distinct and often pronounced odor of black walnuts; penicilli as described 



above. 



The species description is based primarily upon NRRL 795. This strain 

 was isolated by Thorn from cheese at Storrs, Connecticut in 1905, and 

 furnished the type material for the species description as published by him 

 in 1910. The strain was designated No. 38, and as such, was sent to various 

 European laboratories. It was subsequently lost by Thom, but was later 

 returned to him by Biourge as the latter's No. 161 and was reentered in the 

 Thom Collection as No. -4733.3. Biourge discussed the species and strain 

 in his Monograph (La Cellule 33: fasc. 1, pp. 260-262, Col. PL IX, PL XIV, 

 fig. 84. 1923) as it appeared on wort gelatine. Biourge's cultural data is 

 presented together with a condensation of Thom's original description based 

 upon potato and bean agars in Thom's Monograph (The Penicillia, p. 252. 

 1930), and a very brief statement regarding the appearance of the culture 

 on Czapek's solution agar. The culture has remained remarkably stable 

 during more than forty years that it has been under laboratory cultivation. 



Two additional entries assigned to this species are contained in our Col- 

 lection: One of these, NRRL 796, w^as received from Biourge as Penicillium 

 frequentans Westling (Thom's No. 4733.63) but proved to belong here. ^ 

 The second, NRRL 797, was brought to this country in 1936 by Dr. Paul 

 Simonart from Biourge's laboratory as the latter's No. 161, P. atramentosum 

 Thom, and thus stems from the same culture as NRRL 795. 



The species does not appear to be widely distributed in nature but pos- 

 sesses sufficient distinctive characteristics in its cultural habits, and to a 

 lesser degree in its structural detail, to warrant its continued recognition. 

 Representatives of the species are occasionally isolated from soil. 



While this species is not regarded as closely related to Penicillium oxali- 

 cum Currie and Thom, we believe that it will be located here more readily 

 than elsewhere because of its velvety habit, its comparatively simple asym- 

 metric penicilli and its elliptical smooth-walled spores. It differs markedly 

 from P. oxalicum in its failure to develop heavy cmsts of conidia and in the 

 development of comparatively deep red to mahogany colors in reverse. 

 The production of a pronounced odor of black walnuts on malt agar is sug- 

 gestive of certain members of the Biverticillata-Symmetrica, particularly 

 P. purpurogenum Stoll. Whatever similarity exists probably represents a 

 coincidence rather than an indication of close relationship. 



Occurrence and Significance 



The common occurrence and wide distribution of Penicillium oxalicum 

 in soil is presumed to indicate an active role in aerobic processes of decom- 

 position. However, specific reports substantiating such activity are lack- 



