BIVERTICILLATA-SYMMETRICA 615 



monly occur upon a variety of organic substrata subjected to air or water- 

 borne contamination. They are frequently isolated from stored grains, 

 forage products, improperly cured lumber, moist paper stocks, tentage, 

 tarpaulins, and other protective fabrics exposed to weathering processes. 



Many species, apparently belonging to this series, have been described 

 by different authors. Of this number, five are recognized in the current 

 treatment. Our selection of species may appear somewhat arbitrary, and 

 in some cases it has had to be based upon non-authentic cultures and what 

 Ave know to be inadequate descriptions. Nevertheless, we feel that a 

 satisfactory separation can be made along the lines proposed. Where 

 definite cultural entities have been assigned to species names, it is with the 

 belief that such entities represent approximately the type of molds origi- 

 nally studied and described. Recognized species are based upon type ma- 

 terial wherever possible, or upon names which, through common usage, 

 have become widely accepted. 



Penicillium funiculosum Thom is by far the most abundant and the 

 most variable species belonging to the series. Included within our diag- 

 nosis of this species are, undoubtedly, cultural patterns described by other 

 workers as separate species. Such a range of variation between strains 

 has been encountered, however, that satisfactory hues of separation are 

 lacking. In its typical aspect the species produces broadly-spreading, 

 strongly funiculose, and comparatively heavily sporing colonies in which 

 the conidial structures arise from aerial ropes of hyphae, rather than from 

 a basal mycelial felt or a submerged mycelium. Colonies show an un- 

 usually wide range of colors in areas of vegetative mycelial growth and in 

 colony reverse. 



Penicillium islandicum Sopp is probably the most distinctive member 

 of the series. Colonies grow somewhat restrictedly upon all media, are 

 comparatively deep, and are more or less tufted rather than conspicuously 

 funiculose ; they are usually marked by a characteristic coloration involving 

 areas of mixed orange, red, and dark yellow-green. 



Penicillium varians Smith is a strongly funiculose form which develops 

 conidiophores of fairly unique pattern. These are regularly short and 

 usually show heavy walls that are dull green in color. The conidiophores 

 usually arise from short cells which simulate rather closely the foot-cells 

 that characterize the bases of the conidiophores in the genus Aspergillus. 



Penicillium verruculosum Peyronel is characterized particularly by its 

 globose and conspicuously roughened spores. Colonies are broadly spread- 

 ing, more or less funiculose, and generally run toward yellow-green colors 

 — seldom, if ever, developing true reds. 



Penicillium piceum Raper and Fennell is characterized by comparatively 

 loose colonies that consist of a network of much branched, interlacing 



