MONOVERTICILLATA 209 



what looser and deeper; consistently heavily sporing, in some strains 

 abundantly; exudate clear, somewhat more abundant than on Czapek; 

 reverse uncolored to very light cream or tan shades; penicilli as described 

 above, but sterigmata more numerous in the verticil, usually 15 to 20 and 

 somewhat longer, measuring 8 to lOju. 



Colonies on malt extract agar (Col. PI. IV) growing somewhat less 

 rapidly than on steep agar, 5.0 to 5.5 cm. in diameter, generally plane and 

 usually showing a thin overgrowth of white to light flesh-colored aerial 

 mycelium (fig. 57B), sporulating to the colony edge; in some strains show- 

 ing a marked tendency to develop sectors; exudate entirely lacking; re- 

 verse and agar in deep blood to wine red shades, this color in reverse on 

 malt agar being one of the main distinguishing characteristics of the 

 species; penicilli as described above, with sterigmata numerous in the 

 verticil and strongly incurved. 



Species description centered upon NRRL 2048, NRRL 2049, and many 

 additional strains showing similar cultural and morphological characteris- 

 tics. The species appears to be fairly abundant in nature and has l^een 

 repeatedly encountered among the molds isolated from deteriorating fab- 

 rics and other material. It should probably be regarded as essentially 

 a soil organism since most of the strains examined have been obtained 

 from organic substrata subject to contact with the soil or to dust contami- 

 nation. 



The forms under consideration are believed to approximate that origi- 

 nally described by Biourge under this name, although no material which 

 can now be regarded as typical, is available to definitely establish this 

 fact. NRRL 735 (Thom's No. 4733.29) received from Biourge in 1924 as 

 type is not acceptable for the species since it produces large, globose coni- 

 dia, colonies almost sterile, and reverse not strongly colored on malt agar. 

 Penicillium chermesinian Biourge was reported to be a monoverticillate 

 form with conidiophores arising from creeping hyphae, conidial areas green 

 to gray olive in color, with conidia small, elliptical and smooth- walled, 

 and with colony reverse on wort, orange-yellow to purplish red to dark 

 reddish l^rown. The strains under observation seem to conform with this 

 diagnosis better than that of any other described species. 



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



118, p. 71, fig. 28. 1910. Also Thom, The Penicillia, 



pp. 197-198, fig. 24. 1930. 



Colonies on Czapek's solution agar slowly spreading, attaining a diame- 

 ter of 2.0 to 3.0 cm. in 12 to 14 days at room temperature, almost velvety 

 in some strains, in others showing a tendency to develop white mycelial 

 overgrowths in central areas (fig. 58A), in still others almost floccose and 



