322 A MANUAL OF THE PENICILLIA 



which characterize that species. Lacking proof of either of these possi- 

 bihties, however, we beheve it desirable to base assignment upon mor- 

 phological characteristics and place the species in the Divaricata. 



PenicilUum jenseni Zaleski, in Bui. Acad. Polonaise Sci.: Math, et Nat. 

 Ser. B, pp. 494-495, Taf. 57. 1927. Thom, The Penicillia, 



pp. 346-347. 1930. 



Colonies upon Czapek's solution agar growing restrictedly, attaining a 

 diameter of 2.5 to 3.0 cm. in 12 to 14 days at room temperature (24°C.), 

 consisting of a basal felt 500^ deep, strongly folded and wrinkled (fig. 85E), 

 with central area raised or depressed, and with subcentral area strongly 

 folded and radially furrowed, the agar underlying this portion of the colony 

 commonly being pulled away from the culture dish, with surface appearing 

 rather loose, finely granular, almost lanose, more or less zonate with mar- 

 gins 1 to 2 mm. wide, yellow-white, shading quickly through court gray to 

 gnaphalium green (Ridgway, PL XLVII) with the ripening of conidia, 

 sporulating abundantly throughout the colony; exudate not produced; 

 odor lacking or indefinite; reverse uncolored to dull peach shades, fruiting 

 abundantly on under surfaces that have pulled away from the culture plate. 

 Penicilli conspicuously divaricate (fig. 86C), often appearing ramigenous, 

 in larger structures usually consisting of a fairly definite terminal cluster of 

 2, 3, or more metulae, in smaller structures commonly not so arranged; 

 conidiophores variable, smooth, arising from the substratum and ranging 

 up to 500ju or more in length by 2.0 to 2.5/x wide, or borne as lateral 

 branches upon trailing hyphae, commonly less than 100m; metulae vari- 

 able, commonly 8 to lOju by 2.0^; sterigmata usually in clusters of 5 to 10, 

 compactly arranged (fig. 86D), usually 7 to 8m by 2.0m with fairly well 

 defined conidium-bearing tubes, producing chains of conidia tending to 

 adhere into loose columns; conidia globose to subglobose 2.0 to 2.5m, with 

 walls delicately roughened. 



Colonies on steep agar growing more rapidly, about 5 cm. in 12 to 14 

 days at room tem.perature, conspicuously and closely furrowed, more or 

 less zonate, with colony texture and color essentially as on Czapek; peni- 

 cilli as described above. 



Colonies on malt agar restricted, about 2.5 cm. in diameter, loose- 

 textured, more or less floccose (fig. 85F), penicilli more consistently mono- 

 verticillate and tending to be ramigenous, with column development more 

 strongly accentuated than upon the above substrata. 



Species description based primaril}^ upon culture NRRL 909 (Thom 

 No. 5010.10) received from the Centraalbureau in 1928 as Zaleski's type; 

 duplicated by a second strain of this same culture received from Baarn in 

 April 1946. Isolates representative of this species are occasionally ob- 

 tained from soil. 



