498 A MANUAL OF THE PENICILLIA 



closely but delicately zonate; growing margin white to light gray-green, 



1 mm wide, quickly becoming darker, fruiting areas at first bluish green 

 near gnaphalium green but shading quickly to slate olive (Ridgway, PL 

 XLVII) and finally to dark olive-gray (R., PI. LII), at 2 to 3 weeks com- 

 monly showing an area of submerged growth up to 2 mm. wide surrounding 

 the colony and bearing scattered penicilli ; reverse yellowish to tan to almost 

 brow^nish black in colony center, with surrounding agar uncolored; exudate 

 lacking or limited in amount, colorless; odor moldy to sourish, strong; 

 conidiophores arising primarily from a tough basal mycelial felt, generally 

 less than 200/x in length by 3.5 to 4.0m wide, slightly sinuous with walls 

 more or less roughened; penicilli asymmetric, consisting of a terminal 

 verticil of metulae or of such a verticil with branches and metulae arising 

 from a lower node, often irregularly branched ; branches usually 10 to 20/x 

 by 2.8 to 3.5ai; metulae usually in groups of 2 to 4, ranging in dimensions 

 from 9.0 to 15ju by 2.5 to 3.5iu; sterigmata usually in groups of 3 to 5 and 

 measuring 7.0 to 9.0iu by 2.5 to S.ojj., with form not distinctive, conidia 

 globose to subglobose, with walls smooth or delicately roughened, mostly 

 3.0 to 3.5m in diameter but variable in size up to 5.0 to 5.5/x. 



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

 4.0 to 4.5 cm. in 2 weeks at room temperature, essentially similar in pattern 

 and coloration to the above, and producing penicilli as described. 



Colonies on malt extract agar attaining a diameter of 5.5 to 6.0 cm. in 



2 weeks at room temperature, with colony center raised, loose-textured, 

 with sub-marginal area sometimes lightly furrowed in a radial pattern, 

 ranging from almost non-sporulating to heavily sporing depending upon 

 the strain, and with marginal zone up to 1.5 cm. sometimes plane, conidial 

 areas in lighter blue-green shades than on Czapek, ranging from gnaphalium 

 green to pea green (R., PI. XLVII); penicilli essentially as on Czapek but 

 with conidiophores more consistently roughened. 



Penicillium puherulum Bainier is occasionally isolated from soil, from 

 decaying vegetation, and from stored cereal grains. 



Species description based upon Thom's diagnosis as furnished to and 

 published by Alsberg and Black (1913) and as republished by Thom in his 

 Monograph (1930), together with our current observations on cultures 

 from the same original source. One of these, NRRL 2040, was received 

 from the Centraalbureau in May 1946 and represents a culture sent to 

 Professor Westerdijk immediately after the publication of Alsberg and 

 Black's work. This strain was isolated from Zea Mays prior to 1913. 

 Another culture, NRRL 1889, was received in August 1942 from George 

 Smith, London School of Hygiene and Tropical Medicine, as No. Ad 113 

 with the accompanying notation: "Obtained by Dr. Birkinshaw from Dr. 

 Thom in 1928 as No. 4876.20 — it appears to be typical." As noted by 



