MONOVERTICILLATA 201 



not especiall}^ common in nature, but they have been encountered from 

 time to time among soil isolates in this laboratory and have appeared 

 among the strains isolated from deteriorating fabrics and other military 

 equipment exposed in tropical and subtropical areas. 



While we cannot assume with certainty that the highly colorful strains 

 we assign to Penicillium multicolor G.-M. and P. duplicate in all details 

 the strain originally examined by the authors of this species, there is con- 

 siderable reason for believing that they must have based their species 

 upon a monoverticillate form similar to those considered above. 



Penicillium implicatum Biourge var. aureo- marginatum Thorn (The Penicillia, 

 pp. 211-212. 1930) created to include highly colored strains characterized by yellow- 

 orange colony margins and yellow to reddish in reverse, is believed to represent P. 

 multicolor G.-M. and P. Strains with conspicuously yellowed colony margins sug- 

 gesting P. implicatum, but growing somewhat more rapidly and generally producing 

 conidial areas in lighter blue-green shades, are occasionally encountered. Such a 

 culture is contained in our Collection as NRRL 764. While we now regard it as a 

 variant of P. multicolor it complies quite satisfactorily with Thorn's diagnosis of P. 

 implicatum var. aureo-marginatum as published in 1930. 



Penicillium implicatinn Biourge, in ^Monograph, La Cellule 33: fasc. 1, pp. 



278-280; Col. PI. IX and PI. XIV, fig. 82. 1923. Thom, The 



Penicillia, pp. 210-211. 1930. 



Colonies on Czapek's solution agar (Col. PI. IV) growing restrictedly 

 1.5 to 2.0 cm. diameter in two weeks at room temperature, 200 to 300/x 

 or more deep, with growing margin thin, narrow, and white (fig. 55A), 

 often growing irregularly, gradually spreading to several centimeters with 

 or without traces of zonation after several weeks, close-textured, tough, 

 velvety or nearly so, very heavy sporing, umbonate, piled in center, show- 

 ing some tendency to form crusts of conidia in age, nickel green to dark 

 porcelain green (Ridgway, PI. XXXIII) or dark Russian green (PI. XLII) ; 

 odor indistinct, weak or lacking; exudate lacking or limited, in small drop- 

 lets, colorless, yellowish or in red-brown shades; reverse and agar yellow 

 to orange to deep red-brown or maroon or occasionally purphsh shades; 

 conidiophores short, mostly under 100m long by 2.0 to 2.5iu in diameter, 

 arising generally from the substratum in a dense stand (fig. 55E) or occa- 

 sionally borne as branches from traihng hyphae, smooth or nearly so; 

 penicilli usually strictly monoverticillate but with an occasional branch 

 which bears a verticil of sterigmata but retains its monoverticillate char- 

 acter, bearing conidial chains in loose columns up to 200 fx or more in length; 

 sterigmata closely packed, mostly 8 to 12 in the verticil, ranging from 9 

 to 12/i by 2.0 to 2.5m (fig- 55F); conidia elliptical, 2.5 to 3.0/i by 2.0 to 2.5ju, 

 many subglobose, 2.5 to 3.0m, occasionally larger up to 4.5 to 5.0m, heavy- 

 walled, smooth or delicately roughened, dark green in mass. 



