MONOVERTICILLATA 203 



Colonies on steep agar growing more rapidly, attaining a diameter of 

 3.0 to 4.0 cm. in two weeks at room temperature, radiately wrinkled (fig. 

 55B), particularly in central areas with marginal zones 1.0 to 1.5 cm. 

 almost plane, somewhat zonate at center, very heavily sporing, in bluish 

 gray-green shades to dark bluish gray-green (R., PI. XLII) in some strains 

 to gray-green approximating storm gray to castor gray (R., PI. LII) in 

 others; colony texture as on Czapek; penicilli as described above but pro- 

 ducing columns of conidia up to 200^ or more in length, often producing 

 definite crusts. 



Colonies on malt extract agar 2.5 to 3.0 cm. in two weeks, plane (fig. 

 55C), often somewhat zonate in central areas, colony colors as described 

 on Czapek; reverse in lighter colors, never reaching the deep red-brown or 

 maroon shades described above; penicilli as described on Czapek, bearing 

 chains of conidia in loose columns, 200/x or more in length, forming definite 

 crusts in old cultures. 



Species description centered upon NRRL Nos. 2054, 753, 743, and 

 numerous other strains possessing essentially the same cultural and mor- 

 phological characteristics. The species as described is drawn in broad 

 enough terms to include a group of strains differing somewhat in particu- 

 lar characteristics, but showing sufficient similarity in general appearance 

 and growth habits to be considered together. These forms are fairly 

 common in soil and characteristically appear in soil dilution plates as 

 restricted, heavily sporing, dark blue-green colonies with reverse in orange- 

 brown to maroon shades. They occur frequently on fabrics and mihtary 

 equipment undergoing slow microbial attack. They are world-wide in 

 distribution. 



Typical strains of Penicillium implicatum upon all substrata show coni- 

 dial areas in deep blue-green shades, with the blue element pronounced 

 or even dominant. However, occasional strains, otherwise typical, de- 

 velop conidial areas in yellow-green rather than blue-green shades. Recog- 

 nition of a variety covering these forms is not considered advisable since 

 the color change from strain to strain is progressive rather than abrupt 

 and no satisfactory line of separation can be drawn. It is sufficient if the 

 worker recognizes the presence of such variation. 



Penicillium sublateritium Biourge, in Monograph, La Cellule 33: fasc. 



1, pp. 315-317; Col. PI. X and PI. XVI, fig. 92. 1923. Thom, 



The Penicillia, p. 222. 1930. 



Colonies upon Czapek's solution agar restricted in growth, 1 to 2 cm. 

 in diameter in 10 to 12 days at room temperature, appearing velvety 

 with a white margin less than 1 mm. wide, rather deeply radiately wrinkled 

 or furrowed, buckled in center (fig. 55D), faintly zonate, mycelium con- 



