602 A MANUAL OF THE PENICILLIA 



number, fragmentary. Perithecial initials are composed of a pair of short 

 coiled hyphae which complete one or two turns, and around which the asco- 

 carp develops directly {fide Emmons). 



Species description based upon NRRL 1010, from the Thom Collection 

 as No. 5357.208, received in 1933 from Professor G. R. Bisby, University 

 of Manitoba, Winnepeg. as an isolate from soil. This culture was included 

 in Emmons' study (1935), and formed the basis for his observations and 

 comments regarding PenicilUum luteum Zukal. It was sent to the Cen- 

 traalbureau by Thom in 1936 and was returned to us by them in June 1946. 

 The two substrains remain essentially alike but the latter produces peri- 

 thecia in somewhat greater abundance, hence, is maintained in our Collec- 

 tion as a separate accession, NRRL 2102. This culture is believed to 

 closely approximate the form studied originally by Zukal. Insofar as we 

 are aware, this culture represents the third or fourth strain of Zukal's 

 species reported since P. luteum was described almost 60 years ago. Weh- 

 mer (1893) discussed a culture with transversely banded ascospores, al- 

 though he subsequently identified Thom's No. 11 (with spinulose asco- 

 spores) as representing Zukal's species. Derx (1925, 1926) seems to have 

 had a culture that conformed with Zukal's description, and it was in this 

 culture that he reports having demonstrated heterothallism. Insofar as 

 we know, Derx's observations have not been confirmed by other investi- 

 gators, although his report seems entirely credible. Studying a different 

 strain, than that upon which Derx's observations were based, Emmons 

 failed to secure evidence of heterothallism and reported the production of 

 abundant ascospores in cultures derived from single spores. Strain vari- 

 ation may possibly account for the contradictory reports. In any case, 

 there is great need of additional study on this matter. 



There has been much speculation as to the characteristics of Zukal's 

 species, and various types of ascosporic Penicillia which produce yellow 

 colonies have been assigned to it. The species was discussed by Wehmer 

 in 1893 and again in 1897. We do not know the type of culture with which 

 he worked, but we do know that in 1905 he identified Thom's strain No. 11 

 as PenicilUum luteum Zukal, and it was so published by Thom (1910). 

 Additional study and the examination of other cultures subsequently led 

 Thom to regard it as P. wortmanni Klocker (Thom, 1930, p. 448). It is 

 now recognized as P. vermiculatum Dangeard (see p. 583). When it was 

 still ascosporic, the culture in question produced elliptical, spinulose spores 

 in contrast to the banded spores reported by Zukal, The rediscovery of 

 cultures producing banded ascospores has reaffirmed the validity of Zukal's 

 species as originally reported. The name is applied to the series of biver- 

 ticillate-symmetrical Penicillia producing ascospores because it is at one 



