BIVERTICILLATA-SYMMETRICA 613 



Symmetrica. Conversely, some penicilli in P. dudauxi are branched and 

 asymmetrical, hence suggest the pattern regarded as characteristic of P. 

 davigerum. In describing the latter species Demelius (1923) called atten- 

 tion to the yellow stalks of the coremia, and it is possible that in her descrip- 

 tion and figures the prevailing pattern of the penicillus was misinterpreted. 

 It is likewise possible that she may have been dealing with a strain some- 

 what transitional between the two species as they are understood by us. 

 Until the relationship of the two species can be clarified by the isolation 

 and examination of additional strains, we believe that the user of the Man- 

 ual will benefit by the separation here proposed. 



A cultiu'e received from the Centraalbureau in March 1946, as Penicil- 

 lium gmnulatum Bainier from Ciferri in 1933, deserves special considera- 

 tion. This strain, maintained by us as NRRL 2151, produces rapidly 

 spreading colonies with conspicuous coremia up to 4 mm. high arranged in 

 more or less well-defined zones in central to subcentral colony areas. Colo- 

 nies are characterized by the production of an abundant, heavily encrusted, 

 yellow mycelium and dark yellow green conidial areas as seen in many of 

 the Biverticillata-Symmetrica. Furthermore, conidia are comparatively 

 heavy-walled and strongly elliptical as in many members of this Section. 

 It differs from typical members of the section, however, by producing bi- 

 verticillate penicilli that are characteristically irregular in pattern, although 

 an occasional structure appears more or less symmetrical. Walls of conid- 

 iophores and cellular elements of the penicilli are entirely smooth. Unlike 

 most members of the section, no red pigmentation has been observed on any 

 substratum tested. Its obvious affinities, except for the pattern of its 

 penicilli, appear to be with P. dudauxi Delacroix, although the culture 

 does not conform closely enough to be considered a member of this species. 

 Should other strains approximating the above be encountered, recognition 

 of an additional species in the P. dudauxi series should be seriously con- 

 sidered. Under no consideration can the culture be regarded as repre- 

 senting P. gramdatum Bainier which is lacking in yellow color, and which 

 produces large biverticillate, asymmetrical and conspicuously roughened 

 penicilli that are entirely characteristic of the Fasciculata (see p. 544). 



Occurrence and Significance 



Penicillium dudauxi appears to be fairl}^ abundant in nature and to be 

 widely distributed. It is possibly significant that two of the strains cited 

 above were isolated from deteriorating canvas. Others have come from 

 soil and from decaying vegetation. 



Borquelot and Graziani (1892) studied the physiology of the species. 

 Dox (1910b) reported Penicillium dudauxi to be the best catalase producer 

 of twenty-two species of Penicillium studied. 



