PENICILLIUM 



159 



en masse, are among the characteristics employed in separating 

 the assemblage into groups of species. 



hnportant species and their activities. Fenicilliiim expanswn is 

 responsible for a great deal of the spoilage of apples, pears, and 

 grapes in storage. Two species of Penicillium, P. italicum, a 



Fig. 55. A and B. Stages in endoconidial formation by Thielaviopsis bast- 

 cola. C. Chlamydospores of T. basicola. (After Brierley.) D. Cleisto- 

 thecium of Thielavia basicola. E. Ascospores. F. Ascus. 



blue-green mold, and P. digitatiim, an olive-green mold, occur on 

 citrus fruits in storage. Fenicilliinn piirpiirogemmt spots priat 

 paper, books, and engravings. Textile fibers, paper pulp, and 

 lumber are stained and discolored, and consequently lowered in 

 market value, by species of Penicillium. Frequently P. criista- 

 ceum has been isolated in chronic pulmonary disorders in man, 

 but its etiolomc role in human disease has not been established. 

 By hydrolyzing the butter fats which produce such volatile acids 

 as caproic, acetic, butyric, and capric, P. roqiieforti imparts to 

 cheese a piquant flavor. FeiiicilUimi camemberti flavors camem- 

 bert cheese by means of the products of hydrolysis of casein. 



