34 CULTURAL STUDIES OF SPECIES OF PENICILLIUM. 



ciated with studies of this species in recent literature (Powell, 20 

 Smith 22 ), this name is allowed to stand, at least until we have more 

 information. 



CULTURAL DATA. 



Color, shades of olive green; reverse brown or dark brown, especially in sugar media; 

 color in media, none or slightly yellowish. 



Odor, associated with smell of rotting oranges, strongest upon cane-sugar media. 



Fifteen per cent gelatin in water, weak growth, not adapted for this species; lique- 

 faction none, slowly accomplished in gelatin to which sugar is added; litmus reac- 

 tion acid. Potato agar and bean agar, colonies as described above, rather poor growth 

 which becomes enormously increased upon the addition of cane sugar. Potato plugs, 

 excellent growth. Raulin's fluid, colony colorless. Cohn's solution, germination 

 only. 



Synthetic fluid (Dox's), carbon supplied as: Cane sugar, germinated only. Lac- 

 tose 3 per cent, germinated but no growth. Lactic acid, 0.9 per cent, germinated 

 only. Levulose 3 per cent, germination only. Galactose 3 per cent, slight growth. 

 Glycerin 3 per cent, germination. Potato starch 3 per cent, slight or no growth. But- 

 terfat, germination only. Conidia inoculated into this fluid with various sources of 

 carbon germinated but never developed normal colonies. 



Milk. — This species never produced vigorous growth upon milk. 



At 37° C, killed; check at 20° C. grew well. 



PENICILLIUM ROQUEFORTI Thorn. 



U. S. Department of Agriculture, Bureau of Animal Industry, Bui. 82, pp. 35-36, 



fig. 2, 1906. 

 Report Storrs Agricultural Experiment Station, 1905, p. 111. 



Syn. P. glaucum, various authors — not Link or Brefeld. 

 Colonies on potato agar or lactose gelatin quickly turning green, becoming a dirty 

 brown when old, velvety strict, indeterminately spreading by large main radiating, 

 branching hyphse, giving a somewhat uneven or indefinite margin, which gets a white, 

 fibrous, almost spider-web appearance from its alternation of submerged parts of 

 hyphse with short prostrate aerial loops. Reverse of colony yellowish white. 

 Conidiophores arising separately and in acropetal succession from the growing parts 

 of submerged hypha? (comparatively few aerial parts, but some), 200-300/i septate. 

 Fructification 90-120// or at times 160 by 30-60/z at broadest place, usually appear- 

 ing double by the divergence of the lowest branch; branchlets ("basidiophores") 

 irregularly verticillate, bearing crowded verticils of appressed conidiiferous cells 

 (basidia), 9-11 by 2.5/z with long, divergent chains of conidia. Conidia bluish green, 

 cylindrical to globose, smooth, rather firm walled, 4-5/* in diameter, germinating by 

 a straight tube. Colonies do not liquefy sugar-gelatin, though they soften it some- 

 what. Fungus on plain gelatin or potato agar changes litmus from red to blue very 

 rapidly and strongly almost from the beginning of the growth. Fruiting period short, 

 but one crop of spores upon the mycelium. Cosmopolitan and omnivorous, or nearly 

 so. Characteristic of Roquefort and related types of cheese. 



The mold of Roquefort and related types of cheese has been com- 

 monly designated in dahy literature as P. glaucum Link. Such 

 citations refer to this fungus, though many times referring to it as 

 "the common green mold." Although it is not restricted in its 

 habitat to cheese, this species is so identified with the ripening process 

 of Roquefort cheese (in which pure cultures are used) that any one 



