514 A MANUAL OF THE PENICILLIA 



a diameter of 5.5 to 6.0 cm. in 8 to 10 days, essentially as described above 

 in pattern and texture; penicilli generally larger and conidia commonly 

 showing greater irregularity in dimensions. 



Colonies on malt agar attaining a diameter of about 5 cm. in 8 to 10 days, 

 plane (fig. 131B), comparatively thin, with surface appearing definitely 

 mealy or granular, occasionally developing definite and fairly conspicuous 

 coremia; conidiophores as on Czapek but often appearing rough in the 

 area just above the agar surface, with penicilli essentially as on Czapek 

 but with spore chains commonly up to 350/i in length. 



Species description based upon such representative cultures as NRRL 

 973 (Thom No. 4189) isolated from apples in 1917 by Drs. J. S. Cooley 

 and Charles Brooks, Bureau of Plant Industry; NRRL 976 (Thom No. 

 4852) isolated from apples by Dr. Cooley in 1926; and NRRL 977 (Thom 

 No. 4933.1) isolated by Professor F. D. Heald. Of six strains received in 

 February 1946 from the Centraalbureau under the name Penicillium ex- 

 pansum, three (labelled "from Carica papaya," "No. 10b," and "No. 37," 

 re^jectively) duplicate NRRL 973; the others (labelled "v. Luijk a," "v. 

 Luijk ,3," and "No. 35") duplicate NRRL 976. NRRL 979 (fig. 131C) 

 cited in Thom's Monograph (1930, p. 412) as P. elongatum Dierckx from 

 Professor A. W. Povah, as Thom's No. 5031.25, is regarded as representa- 

 tive of P. expansum (see p. 515). 



Hundreds of strains belonging to this series have been isolated from 

 naturally infected products. Workers in the fields of fruit storage and 

 distribution find typical strains of Penicillium expansum to be the principal 

 agent responsible for losses from storage rot. Coremia with white or more 

 or less colored stalks and green heads composed of massed penicilli are 

 abundantly observed on apples, pears, quinces and related fruits, also on 

 grapes and cherries as they rot slowly in storage packages. Cultures from 

 these penicillate heads produce the usual type of P. expansum already de- 

 scribed, and conidia from these cultures regularly reproduce the rot found 

 in the stored product which carried its infection from the field to the store- 

 house. Corda described and figured such coremia (Prachtflora, p. 54, 

 PI. XXV. 1839) as representing his species Coremium vulgare. Cultures 

 from many coremia, as collected, clearly show that if such heads consist 

 of massed penicillate fruits, the conidia from them will grow in ordinary 

 culture media as Penicillia in which the coremifonn nature of the species is 

 represented by the more or less definite fasciculation of the conidiophores. 

 Only rarely are large coremia comparable to those seen on fruit reproduced 

 in agar cultures. 



In handling rotting fruit and other material showing moldiness, numer- 

 ous mycologists in different laboratories and at different times have isolated 

 and described, or described directly from natural substrata, various species 



