ASYMMETRICA-DIVARICATA 323 



Penicillium jenseni is included in the Divaricata since the majority of 

 the penicilli show this basic pattern. Many structures, however, appear 

 clearly monoverticillate with individual penicilli borne singly on short 

 branches or, more commonly, in irregular terminal groups in the manner 

 typical of the Ramigena series (see p. 239). While we regard the present 

 placement as correct, the probable relationship of the species to the Mono- 

 verticillata, possibly as a transitional form, should not be disregarded. 



Penicillium chrzaszczi Zaleski (Bui. Acad. Polonaise Sci.: Math, et Nat. Ser. B, 

 pp. 464-466; Taf. 48. 1927) is believed to be synonymous with P. jenseni Zaleski as 

 described above. The type culture of P. chrzaszczi as maintained in this Laboratory 

 since 1928 (NRRL 903), and as returned to us in March 1946 from the Centraalbureau, 

 strikingly resembles P. jenseni in culture upon Czapek's solution agar with or without 

 the addition of steep liquor. On malt agar, colonies are somewhat heavier sporing 

 but show the same tendency to grow restrictedly . The penicilli are more consistently 

 biverticillate and generally appear in fairly compact fruiting structures (resembling 

 P. soppi) with the ramigenous habit noted for P. jenseni less commonly observed. 

 Conidiophores of NRRL 903 are smooth-walled, variable in length up to 400 to 500m 

 by 2.0 to 2.5fj.; with metulae mostly about 8 to 10m by 2.0m, slightly enlarged at the 

 apex, bearing sterigmata in compact clusters of 5 to 12 measuring about 6 to 8m by 

 2.0m; conidia globose to subglobose, 2.0 to 2.5m in diameter with walls finely roughened. 

 Sterigmata and metulae commonly appear more or less inflated but this character is 

 not sufficiently constant to be of diagnostic value. 



Occurrence and Significance 



Members of the series appear to be widely but not abundantly distrib- 

 uted in nature. Penicillium canescens and P. jenseni are occasionally 

 isolated from soil, whereas P. nalgiovensis is known only as the type iso- 

 lated from cheese by Laxa in Bohemia. 



Little information regarding biochemical or physiological characteristics 

 is available. Bowen (1941) reported Penicilliiim canescens capable of 

 destroying untreated flannel air filtration bags in less than a month in 

 mines in South Africa. The best protection of the material was afforded 

 by cuprinol, whereas various substances such as copper oleate, creosote 

 and others gave good results for special purposes. Chrzaszcz and Tiukow 

 (1929) reported limited production of citric acid by P. jenseni and P. 

 chrzaszczi, two species that are now regarded as synonymous. Laxa 

 (1932) briefly discusses the significance of P. nalgiovensis in the ripening 

 of Ellischauer cheese. 



Penicillium nigricans Series 



Outstanding Omracters 



Colonies growing rather restrictedly upon most substrata, consisting of a 

 close-textured basal felt with surface variously consisting of a network 

 of trailing hyphae or appearing velvety; conidial areas in dull, often 



