294 A MANUAL OF THE PENICILLIA 



lated from nature which seem to be of hke origin, although definite proof 

 is lacking. One such culture, received in July 1945 from Dr. O. G. de 

 Lima, Recife, Brazil, approximated P. citrinum Thom physiologically by 

 producing citrinin, and in morphological and cultural characteristics du- 

 plicated this species in all except conidial color. The strain is discussed 

 elsewhere as NRRL 2145 (see p. 349). 



Occurrence and Significance 



Penicillinm lilacinum Thom is among the most common of all soil fungi. 

 It seems to occur regularl}^ upon decaying vegetation in the later stages of 

 decomposition and may be isolated less commonly from almost any type 

 of organic substrate exposed to air-borne dust and a fairly humid atmos- 

 phere. It is very tolerant of many chemicals. Thom (1930) reported 

 its occurrence in nickel-electrotyping baths. Lockwood (1936) isolated 

 the species from 9 per cent sodium acetate solutions. Trabut (1895) pro- 

 visionally assigned the name P. cupricum to a mold producing "rose- 

 colored conidia" isolated from a 9.5 per cent solution of CUSO4. The iden- 

 tity of Trabut's mold remains obscure, but it possibly represented a highly 

 colored strain of P. lilacinum. In our experience P. lilacinum has been 

 isolated from various chemicals in solution, mostly acidic, and appears to 

 be one of the most common molds producing "bottle imps" in laboratory 

 reagents. Heyes and Helden (1932) employed P. lilacinum as one of 

 five Penicillia to test resistance of artificial silk to mold damage. Con- 

 siderable "tendering" of the silk occurred prior to the appearance of any 

 microscopically detectable injury to the fibers. Acetate silk was more 

 resistant than other types tested. Schanderl (1942) reported P. ame- 

 thystinum (possibly P. lilacinum of this Manual) as capable of assimilating 

 atmospheric nitrogen. 



Spicaria violacea occurs in nature under conditions similar to those favor- 

 ing P. lilacinum, although apparently less commonly. No biochemical 

 or physiological studies have been reported. Penicillium humuli was 

 isolated from hops but no information was supplied regarding its possible 

 significance in nature. 



Penicillium janthinellum Series 



Outstanding Characters 



Colonies spreading broadly, becoming gray, gray-green, or pale bluish 

 green in conidial areas; vegetative mycelium becoming orange, orange- 

 red or reddish purple in some strains, in others remaining white or 

 nearly so; surface growth varying from almost velvety to definitely 

 floccose depending upon the strain and species, occasionally developing 

 ropes; reverse at first colorless, and in some strains remaining so, in 



