304 A MANUAL OF THE PENICILLIA 



Penicilliuni simplicissimimi (Oud.) Thorn, in The Penicillia, pp. 335-336, 



fig. 51. 1930. 

 Synonym: Spicaria simplicissinia Oudemans, in Nederl. Kruidk, Arch, 

 ser. 3, 2: 763. 1903. See also Jensen, Cornell Agr. Exp. 

 Sta. Bui. 315, p. 493, fig. 127. 1912. 



Colonies on Czapek's solution agar attaining a diameter of 4.0 to 4.5 

 cm. in 12 to 14 days at 24°C., 0.5 to 1.0 mm. deep (fig. 81C), with surface 

 growth loose to almost velvety, composed of a network of trailing and 

 branching hyphae borne upon a tough basal felt, at first white, but later 

 developing abundant conidial heads and becoming pale blue-green near 

 light celandine to artemisia green (Ridgway, PI. XLVII) in marginal and 

 submarginal areas with the ripening of conidial structures, central colony 

 area often somewhat raised and submarginal areas marked by more or less 

 well-developed radial furrows; azonate or slightly zonate in some strains; 

 vegetative hyphae thin, rarely e.xceeding 2.0^ in diameter, uncolored; exu- 

 date limited to abundant, colorless; odor lacking or indefinite; colony re- 

 verse colorless or in yellow shades, in some strains approximating straw 

 to amber yellow (R., PI. XVI). Penicilli usually not abundantly produced, 

 fairly late in developing and mostly concentrated in a narrow to relatively 

 broad marginal zone, asymmetric, strongly divaricate, rarely showing true 

 branches but commonly consisting of more or less well-defined terminal 

 clusters of 2 to 4 divergent metulae bearing verticils of sterigmata (appear- 

 ing essentially monoverticillate), and borne upon ascending conidiophores 

 arising mostly from the substratum, or smaller structures consisting of 

 verticils of sterigmata only, borne upon short conidiophores arising from 

 vegetative hj^phae or upon side branches at lower levels on the ascending 

 conidiophores; penicilli characterized by long, divergent to loosely-tangled 

 chains of conidia; conidiophores with walls roughened, varying greatly in 

 dimensions, ranging from 200 to 800^^ or longer by 2.5 to S.O/j. in larger 

 structures, to very short, commonly less than 50/x by 2.5/x, when arising as 

 lateral branches; metulae variable and often unsatisfactorily identifiable, 

 mostly 12 to 18/x by about 2.5^, but showing a range from 10 to 25/x by 

 2.5 to 3.0/x; sterigmata mostly in clusters of 4 to 10, measuring 8 to lO/z 

 in length and 2.0 to 2.5iu wide in basal portion, tapering abruptly to a 

 conspicuous, narrow conidium-producing tube about 2.0 to 2.5^ by 1.0^; 

 conidia at first strongly elliptical, usually remaining so but not infrequentlj^ 

 appearing subglobose, mostly 2.5 to 3.0m in long axis with walls finely 

 echinulate. 



Colonies on steep agar growing more rapidly than on Czapek, attaining 

 a diameter of 5.5 to 6.0 cm. in 10 to 12 days, heavily sporulating in central 

 colony areas, conspicuously zonate and with successively older areas rang- 



