12 A MANUAL OF THE PENICILLIA 



to an organism which he beHeved to represent Brefeld's strain. He pro- 

 posed to move all of the forms producing hard-walled perithecia out of 

 Penicillium into Carpenteles. Van Beyma (1933) accepted the change 

 with some reservations, but for adequate reasons others have not cared to 

 disinter Langeron's generic usage. Such transfer is illogical and consti- 

 tutes a basis for unnecessary confusion, for strains maintained in the labo- 

 ratory may quickly lose their ascospore-producing power. The same 

 strain, when first picked up out of doors may be readily identifiable as 

 Carpenteles, only to later have to be referred to the genus PenicilUum when 

 perithecia are no longer developed. The transfer of a small fraction of a 

 great group of obviously related organisms to a new genus because an 

 occasional strain produces ascospores, seems to us a fantastic interpreta- 

 tion of the rules of nomenclature. Enough has been said to show the 

 background of our conclusions that the cause of a permanent nomenclature 

 is better served by emending Link's inadequate diagnosis of the genus 

 Penicillium to include the citation that some series in the genus produce 

 asci, than by recognition of any separate name or names for the ascospore 

 producers. This course is likewise supported by historical considerations 

 since Brefeld (1874), Zukal (1889), and others described ascosporic forms 

 as species of Penicillium. 



The series with firm perithecia seem to pass directly into forms produc- 

 ing sclerotia, from which a potential ascogenous center has possibly been 

 obliterated. No one has found it possible to obtain asci from proved 

 sclerotium producers, although morphologically these may be quite similar 

 to other strains found in nature as perithecium and ascus producers. 



In summary, the authors are fairly familiar with accepted rules of no- 

 menclature, and are intimately acquainted with the literature of Peni- 

 cillium. More important, we have had first hand cultural experience 

 with thousands of strains of Penicillia in comparative cultural studies, and 

 representing the whole range of morphology in the group. We believe 

 that the system of nomenclature to be followed in a Manual of this type 

 should combine due consideration of the views of our predecessors with 

 the presentation of a workable system of descriptive diagnoses which will 

 enable the user to identify the molds he has in culture. With this ideal in 

 mind we apply the generic name Penicillium to the whole group of strictly 

 penicillate green molds, with or without ascospore production. Variant, 

 or mutant strains or species in which the factor for green or blue-green 

 color is not evident are retained in Penicillium, as are also all other mutant 

 types developed from parent strains clearly representing members of the 

 genus Penicillium. 



Gliocladium of Corda is used for a group in which the general branching 

 of the conidial apparatus simulates that of Penicillium, but in which the 



