POLYVERTICILLATA 669 



tions were very meager, and his illustrations were idealized to such a degree 

 as to preclude positive reidentification of his forms by subsequent inves- 

 tigators. 



WTiile we are by no means certain of our identification, we have recently 

 examined a culture isolated in 1940 by P. H. Waring Webb from decom- 

 posing chicken feathers at Beltsville, Maryland, which we have provision- 

 ally diagnosed as PenicilUum albicans Bainier. Whether or not our diag- 

 nosis is correct, a discussion of this strain, together with illustrative 

 photographs, will enable us to present the general morphology which is 

 regarded as characteristic of the Polyv^erticillata. 



Penidllium albicans Bainier, in Bui. Soc. Myc. France 23: 18, PI. V, figs. 8 

 and 9. 1907; Thom, The Penicillia, p. 495, fig. 87. 1930. 



Colonies spreading broadly but growing very sparsely upon Czapek's 

 solution agar at room temperature, up to 5 to 6 cm. in two weeks, very thin, 

 with vegetative mycelium limited and almost wholly submerged, uncolored, 

 lightly sporulating throughout; conidiophores arising partly from sub- 

 merged hyphae, partly from trailing aerial hyphae which occasionally col- 

 lect into delicate ropes, usually short, about 20 to 35^ but sometimes longer, 

 of variable diameter up to 5 or 6^, smooth-walled with content often ap- 

 pearing granular or globular; penicilli variable in form and dimensions, 

 occasionally large and several times rebranched, but often fractional and 

 consisting of few and irregularly arranged cellular elements. 



Colonies on steep agar fairly luxuriant (fig. 168A), attaining a diameter 

 of 5.0 to 6.0 cm. in 10 to 14 days at room temperature, with vegetative 

 mycelium largely submerged but supporting abundant and conspicuously 

 funiculose aerial growth, heavily sporing throughout, at first white to light 

 cream, in age becoming light buff or even showing pale avellaneous shades, 

 particularly in the mycelial growth and sporulating areas adjacent to the 

 substratum; odor lacking; exudate not produced; reverse in deep tan to 

 light brown shades; conidial structures abundantly produced, borne pri- 

 marily upon short conidiophores arising from aerial hyphae and ropes of 

 hyphae; conidiophores variable in length but mostly very short, about 20 

 to iOfx, tj'pically consisting of a few short thick cells up to 6 to 7m in diam- 

 eter, smooth-walled; penicilli variable in size and pattern, commonly very 

 large and 3 or 4 times branched below the sterigmata, often but not con- 

 sistently symmetrical, with cellular elements closely appressed to form a 

 very compact fruiting head (fig. 168B and C). Branches variable in form 

 and size, usually becoming smaller at successive levels away from the main 

 axis; metulae not readily distinguishable from the uppermost branches, 

 about 8 to 10 X 2.5 to 3.0n; sterigmata about 6 to 7/i by 2.0/i with conidium- 



