180 A MANUAL OF THE PENICILLIA 



presented above. The culture differs from NRRL 720 and NRRL 2052 

 primarily in producing colonies more highly colored in reverse. 



Penicillium pnrpurrescens (Sopp) n. comb., as diagnosed above, would 

 include the following species : 



Citromyces virido-albus Sopp (Monogr. pp. 131-132, Taf. XIII, fig. 98 and Taf. 

 XXII, fig. 12. 1912) is believed to be synonymous with P. purpiin-escens (Sopp) 

 n. comb. Like the latter species, C. virido-albus was a monoverticillate (citromyces- 

 like) form isolated from soil which showed colony reverse in reddish to brown shades 

 and produced large conidia 3 to 7fj. in diameter with walls irregular and rough 

 ("thorny"). 



Penicillium baiiolum Biourge (Monogr. La Cellule 33: fasc. 1, pp. 305-306; Col. 

 PI. VIII and PI. XIII, fig. 74. 1923) is also believed to belong with P. purpurrescens 

 (Sopp) n. comb, as considered here. The species was described as a monoverticillate 

 form producing large conidia, at first elliptical then nearly globose and rugose- 

 echinulate when ripe. Thom's observations (1930) on Biourge's type were confirma- 

 tory. The colonies were reported to be dirty gray -green and the species was placed 

 near the end of the section that included P. frequentans Westling. If Biourge's 

 species were to be recognized, it would need to be regarded as transitional between 

 P. frequentans (with smooth or finely roughened conidia) and P. purpurrescens (with 

 the conspicuously roughened conidia described above). Examination of many 

 strains assignable to these two species has failed to reveal any need for recognition 

 of an intermediate form. 



Penicillium spinulosum Thom, in U. S. Dept. Agr., Bur. Anim. Ind., Bui' 

 118, p. 76, fig. 32. 1910. See also Thom, The Penicillia, pp. 183- 



184, fig. 21. 1930. 



Colonies on Czapek's solution agar growing fairly rapidly, 4.5 to 5.5 

 cm. in diameter in 12 to 14 days at room temperature, consisting of a 

 loose-textured felt partially submerged, but predominantly aerial (fig. 

 51A), bearing conidiophores mostly as branches from loosely interlacing 

 hyphae but commonly from submerged mycelia in marginal areas, more 

 or less radiately wrinkled, rarely zonate, up to 1 or 2 mm. deep in central 

 areas, heavily sporing in some strains, lightly in others (tending toward 

 sterihty under long cultivation), in dull green shades from sage green 

 through slate olive to deep slate olive (Ridgeway, PI. XL VII) ; odor very 

 faint; exudate lacking or very limited; reverse almost colorless to light 

 gray shades, occasionally showing a pinkish tinge; penicilli bearing spore 

 chains in loose columns up to 100 to 150m long; conidiophores varying in 

 relation to their origin, usually fairly long, mostly 80 to lOOyu but up to 

 200 to 300/i when arising from the substratum, to quite short, 25 to 50m 

 when arising as branches from aerial hyphae (fig. 51C), mostly 2.5 to 

 3.0m in diameter, with walls almost smooth in some strains to definitely 

 roughened in others (fig. 48C), with apices vesicular up to 5.0m in di- 

 ameter, bearing penicilH generally strictly monoverticillate but with an 



