8 A MANUAL OF THE PENICILLIA 



of cheese. Even in his Monograph (1912) this usage remains too indefinite 

 to be verified. His Monograph brought together a mass of descriptive 

 matter and many figures covering some sixty species of Penicilliiim, to- 

 gether with descriptions and ilhistrations (some colored) of forms which he 

 thought to be closely related. Despite the mass of data presented, very 

 few of his species have been identified with certainty by other workers. 

 Insofar as we know, he never distributed any cultures. 



Dierckx published his "Essai" in 1901, in which he sketched his method 

 of work and proposed a series of twenty-five new species with descriptions 

 so brief and inadequate that no one working with the published material 

 succeeded in identifying any of his new species. As noted by Saccardo in 

 the Sylloge, the new names proposed were not supported by descriptions or 

 figures which would identify them. He appears, however, to have left in 

 the laboratory at Louvain, colored plates, descriptive material, and suf- 

 ficient of his cultures to enable Biourge to reidentify and redescribe twenty- 

 two of these forms in 1923. Biourge obviously based his recognition and 

 perpetuation of some of Dierckx's specific names upon the accessory ma- 

 terial left by Dierckx. 



Thom began to study Penicillia in connection with cheese investigations 

 in 1904, published "Fungi in Cheese Ripening" in 1906, his "Cultural 

 Studies of species of Penidllium'' in 1910, and his group concept of classifi- 

 cation of the Penicillia in 1915. In these papers the necessity of compara- 

 tive culture upon standardized media was stressed in contrast to the search 

 for optimum conditions of culture, organism by organism. 



Weidemann in Eel (1907) and Westling in Stocldiolm (1911) used care- 

 ful cultural methods in describing their series of green Penicillia. But 

 neither worker had a large enough collection, nor followed the study long 

 enough, to determine group relationships. 



Bainier, under the general title "Mycotheque de I'Ecole de Pharmacie" 

 (Paris), began publishing descriptions of species of Penicillium in 1905 

 and continued partly separately, partly with Sartory, until 1914. In this 

 series of species many forms were described and figured with meticulous 

 care, hence some of them are readily identified . Efforts were made to main- 

 tain all of these forms in culture at I'Ecole de Pharmacie. Bainier sepa- 

 rated the form described later by Thom (1910) as Penicillium divaricatum 

 and made it the type of his genus Paecilonujces (1907). He also desig- 

 nated P. hrevicaule Saccardo, with its numerous alhed forms, as the basis 

 of a new genus, Scopulariopsis (1907). The separation of both of these 

 groups from Penicillium can be readily justified upon the ground of lack 

 of essential relationship. Bainier adopted Wehmer's genus Citromyces 

 and described his monoverticillate strains as species under that name. 

 Biourge, under the stimulus of Carnoy, began to study Penicillia in 



