570 A MANUAL OF THE PENICILLIA 



this time the long clavate hypha begins to coil terminally in a definitely 

 helical pattern, and it is this structure which specifically distinguishes the 

 species (fig. 144D). Ascospores, although elliptical and spinulose in char- 

 acter, are definitely smaller than those produced by P. vermiculatum and 

 thus serve to further differentiate the species. 



Penicillium spiculisporum Lehman should possibly be considered with 

 the above. Ascospores are of the same general pattern as seen in P. vermi- 

 culatum and P. worlmanni and are intermediate in size between these species 

 and P. helicum. Culturally the species is distinct, since it usually produces 

 little or no yellow pigmentation in the coarse mycelia that surround the 

 perithecia. In contrast to most members of the series, the perithecia of 

 this species are at first white and in age seldom develop darker shades than 

 cream or a light buff, although in his description, Lehman (1920) noted 

 the development of pink tints upon some substrata. The hyphal networks 

 that bound the perithecia are commonly denser than in most species and 

 often simulate a true wall, but in our experience never develop a specialized 

 membrane of differentiated cells. The perithecial initials are somewhat 

 suggestive of those seen in P. wortmanni but are usually less diffuse and 

 often appear as a single, irregularly swollen deeply staining cell that 

 branches profusely (fig. 144E) to produce a knot of fertile tissue which 

 subsequently develops into the perithecium. 



Penicillium bacillosporum Swift, like P. rotundum, produces globose, 

 spinulose ascospores, but shows little additional evidence of possible close 

 relationship to the latter species. Perithecial initials are in the form of 

 two short coiled hyphae and are strikingly similar to those produced in 

 P. hdeum Zukal (Emmons, 1935). Mature perithecia show the basic pat- 

 tern and structure characteristic of the group but are commonly bounded 

 by a more closely knit network of interlacing hyphae than in most other 

 species. The penicilli, while commonly monoverticillate, may be regarded 

 as conforming with the basic pattern of the series since the sterigmata are 

 typically lanceolate and since occasional biverticillately-symmetrical struc- 

 tures are observed. The conidia, however, are quite unlike those of any 

 other Penicillium. These are bacilliform, rod-like, and this character 

 clearly differentiates it from all other known species (fig. 153). Pigmen- 

 tation differs from most members of the series; colonies regularly show 

 hghter yellow shades, with vegetative hyphae showing reddish or greenish 

 tints, and develop colony reverse in various dark brown to green shades 

 rather than reddish or reddish browns. Asci are borne in short chains as in 

 all of the above species. While close relationship is not presumed, this 

 species is perhaps closer to P. spiculisporum than to any other member of 

 the series as shown by the usual absence of bright yellow colors in the 



