ASYMMETRICA-FASCICULATA 529 



For routine laboratory studies it is actually better to obtain such fresh 

 cultures, for they are generally most characteristic of the species. 



Species description based upon the examination of numerous strains 

 some of which are contained in the permanent collections of the Northern 

 Regional Research Laboratory, and a limited number of which represent 

 recent isolates from freshly spoiled citrus fruit. The following cultures 

 may be regarded as representative: NRRL 983, from Dr. H. S. Fawcett, 

 Citrus Experiment Station, Riverside, California, in 1930; NRRL 1293, 

 isolated from a rotting orange, at the Northern Regional Research Labora- 

 tory, Peoria, Illinois, in 1941; and NRRL 1900, from Professor Gladys E. 

 Baker, Yassar College, Poughkeepsie, New York, in 1943. This list could 

 be extended, but to little advantage. 



Two additional species were included in the Penicillium. italicum series 

 by Thom in 1930, namely: P. aeruginosum Dierckx and P. ventruosum 

 Westling. The validity of both usages was questioned at that time and 

 the subsequent examination and comparison of many additional cultures 

 substantiates this belief. 



Penicillium aeruginosum Dierckx (Soc. Scient. Brux. 25: 87. 1901). Dierckx him- 

 self regarded his species as possibly representing P. olivaceum of Wehmer, but in later 

 unpublished notes {fide Biourge, 1923, p. 121) he concluded that it represented Weh- 

 mer's P. italicum, an opinion with which we heartily agree. Biourge in hisMonograph 

 (1923, pp. 121-123, Col. PI. I, fig. 6) re-established the species to cover a strain in his 

 possession which produced prominent coremia and which apparently failed to produce 

 sclerotia as observed by Wehmer (1894) and Thom (1910). Variation within the P. 

 italicum series is great, particularly with regard to the production of prominent fas- 

 cicles or even coremia; while we recognize that strains such as Biourge 's do occur, we 

 cannot believe that they merit recognition as a separate species. 



Penicillium ventruosum Westling (Arkiv for Botanik 11: 57, 112-114; figs. 26 and 

 67. 1911). This species has commonly been interpreted as including members of 

 the P. italicum series that produce conspicuous coremia, which, in marginal colony 

 areas, are often prostrate and may extend for several millimeters beneath the agar 

 surface before emerging to produce conidia. Except for this habit, there is little to 

 separate such forms from the more typical strains which are normally regarded as 

 representing P. italicum Wehmer. The separation might be regarded as valid were 

 it not for the fact that strains varying greatlj' in their tendency to produce coremia 

 can be isolated from miscellaneous collections of rotting citrus fruits, and for the 

 additional fact that the structural details of the penicilli and the measurements of 

 parts including conidia are essentially the same whether or not prominent coremia 

 are produced. Westling suggested the possible relationship of his species to P. itali- 

 cum, and it is our belief that it should be regarded a^synonymous with this generally 

 accepted species. 



Occurrence and Significance 



Although it is occasionally isolated from soil and other substrata, Peni- 

 cillium italicum Wehmer typically occurs on citrus fruits where it produces 



