ASYMMETRICA-FASCICULATA 555 



ceived in 1939 from Dr. C. W. Emmons, National Institute of Health, 

 Washington. The latter strain differs only in producing less heavily spor- 

 ing colonies and conidia that are somewhat smaller and less consistently 

 elliptical. 



Assignment of the above strains to Demelius' Penicillium clavigerum is 

 based upon a number of considerations, including: comparatively large, 

 asymmetric, branched penicilli; coremia up to 3 mm. or more in length; 

 smooth- walled conidiophores; and elliptical smooth-walled conidia 3.0 to 

 4.0m by 2.3 to 3.0/i. These strains differ from her description in developing 

 yellow-green to olive rather than blue to gray -green shades; in exhibiting 

 a less clear cut differentiation into supportive stalks and terminal conidial 

 areas; and in producing conidiophores that are colorless or nearly so in 

 contrast to yellow as reported by her. Her figures of the penicillus and 

 the coremium, though somewhat diagrammatic, are fairly representative 

 of the strains we have assigned to this species. Exact duplication of the 

 above strains with Demelius' culture is not claimed, and it is possible that 

 they should be regarded as representing a new species. However, con- 

 sistent with our practice of not introducing a new name if a published 

 species can be regarded as reasonably representative, we have elected to 

 assign these cultures to P. clavigerum. In the present case, points of 

 similarity are believed to definitely outweigh points of difference, especially 

 since these latter, e.g., colony color and coloration of coremia stalks, may be 

 strongly influenced by the substratum. 



A strain received from the Centraalbureau in February 1946 under this 

 name, as an isolate from canvas made in 1939, produces coremia of the 

 general type described and figured by Demelius, but the penicilli are typically 

 biverticillate and symmetrical. This culture adequately' represents Peni- 

 cillium duclau.vi Delacroix and is further considered under the discussion 

 of that species. 



Occurrence and Significance 



Members of the present series occur as infrequent components of the 

 mycoflora of soils. 



Penicillium claviforme Bainier has attracted considerable attention re- 

 cently as a producer of an antibiotic that is variousl}^ referred to as clavi- 

 formin, patulin, clavacin, etc. (see p. 537). Chain, Florey, and Jennings 

 reported the production of this antibiotic by P. claviforme in 1942. We 

 feel that the name claviformin, which they applied to it, should be adopted 

 since they were the first to obtain the substance in crystalline form. While 

 quantitative comparisons have not been conducted, tests performed at this 

 Laboratory would seem to indicate that strains of P. claviforme are more 

 productive of the antibiotic than other organisms reported to produce it. 



