518 A MANUAL or THE PENICILLIA 



odor pronounced, moldy; penicilli essentially as the preceding but usually 

 somewhat more compact and borne upon shorter conidiophores, commonly 

 100 to ISOjti in length and very coarsely roughened. 



Typical strain produced a limited brown rot (fig. 130D), measuring 1.5 

 to 2.0 cm. in diameter in 8 to 10 days, when inoculated into sound apples 

 (varieties: Golden Delicious and Winter Banana). 



Species description based primarily upon Thom's diagnosis (1930) and 

 upon cultural observations on strains NRRL 968 (Thom's No. 5461.448), 

 received in 1934 from Y. K. Shih, National Wu Han University, Wuchang, 

 China; NRRL 969, isolated as an air contaminant in the Division of Soil 

 Microbiology Laboratory in Washington in 1940; NRRL 943 from C. E. 

 Burnside, isolated from honey bees; and NRRL 1983, received in 1944 

 from Drs. D. K. Miller and A. C. Rekate, Buffalo, New York as a mold 

 capable of producing an antibiotic that inhibited the growth of the tubercle 

 bacillus. A strain received in February 1946 from the Centraalbureau as 

 Thom's No. 5461.448 remains typical of the species and duplicates NRRL 

 968 in all essential details. The species was represented in our study by 

 additional strains isolated from chickens in cold storage by Dr. G. A. 

 Ledingham, Ottawa, Canada. 



Penicillium flavo-glaucum Biourge (Monogr., La Cellule 33: fasc. 1, pp. 130-132; 

 Col. PI. I and PL II, fig. 10. 1923) was described in terms which render its separation 

 from P. crustosum difficult. Colonies were reported by Biourge (1923) and Thom 

 (1930, p. 386) as zonate, pale to dull green in color with bluish green showing only 

 transiently in marginal areas, and as producing crusts of conidia up to 500/;* or more 

 deep, with conidiophores and parts of the penicilli with walls rough. As reported by 

 Thom, and as shown in our current study by a culture received from Biourge in 1924 

 as type, NRRL 948 (Thom No. 4773.61a), this species differs from P. cyclopium pri- 

 marily in producing colonies less blue-green in color and conidiophores more strongly 

 roughened. 



Occurrence and Significance 



Meml;)ers of the Penicilliutn e.rpansiim series commonly occur in soil and 

 upon a wide variety of organic substrata. They are, however, best known 

 for their frequent and typical occurrence upon pomaceous fruits, where 

 they produce a destructive rot, commonly referred to as Penicillium-rot, 

 or "blue mold rot," of apples. Brooks, et. al. (1920) estimated "blue 

 mold" as the cause of 80 to 95 per cent of the total losses from rot of apples 

 in transit and in commercial storage. Other investigators have published 

 comparable estimates. 



Many species and varieties of Penicillium occur upon spoiled apples, 

 cherries, grapes, etc., but extensive experiments by ourselves and many 

 others have shown that the members of the Penicillium expansum series 

 are by far the most prevalent and the most destructive. In inoculation 



