316 A MANUAL OF THE PENICILLIA 



1". Colonies 500 to 1000/i deep, with surface growth loose, more or less floccose; 

 conidial areas in dull blue-green shades; conidia about 2.0 to 2.5m; re- 

 verse orange, becoming rich brown in age P. canescens Sopp 



2". Colonies deeply floccose, 2 to 3 mm. deep; conidial areas in brighter green- 

 ish glaucous shades; conidia about 3.2 to 3.6m; reverse in deep red shades 



near maroon P. nalgiovensis Laxa 



bb. Colony reverse uncolored or in dull peach shades, not developing dark colors; 

 penicilli often appearing somewhat ramigenous P. jenseni Zaleski 



The so-called Penicillium canescens series is probably artificial in char- 

 acter, and is proposed principally to cover species in which the divaricate 

 penicilliis is well marked, but which do not fit very satisfactorily into any 

 other recognized series. A limited degree of relationship is believed to 

 exist between the species represented here. All tend to produce conidial 

 chains in loose columns, all produce long conidiophores (in part), often 

 with fairly well organized terminal penicilli, and all produce globose to 

 subglobose spores. Three species are included, each of which seems to 

 be more or less intermediate between the Divaricata and some other sec- 

 tion of the genus. Penicillium canescens Sopp appears to be transitional 

 between the P. janthinellum and P. nigricans series. Penicillium jenseni 

 often produces comparatively small penicilli that are somewhat ramigenous 

 and suggests a relationship to the Monoverticillata on the one hand, or to 

 the P. citrimmi series through P. corylophilum Dierckx (see p. 341) on the 

 other. Penicillium nalgiovensis Laxa, in colony texture and coloration 

 and in details of structure, possesses characteristics which indicate affini- 

 ties with certain species assigned to the Lanata or Fasciculata. 



Penicillium canescens Sopp, in Monogr. pp. 181-182, Taf. XIX, fig. 136; 



Taf. XXIII, fig. 28. 1912. Thorn, The PenicilHa, 



pp. 347-348. 1930. 



Colonies on Czapek's solution agar growing somewhat restrictedly, 

 attaining a diameter of 3.5 to 4.0 cm. in 10 to 12 days at 24°C., with sur- 

 face more or less floccose, consisting of a loose network of interlacing vege- 

 tative hyphae arising from a compact basal felt, radiately furrowed with 

 central colony area irregularly buckled (fig. 85A), lightly zonate, sporu- 

 lating fairly abundantly, essentially uniform throughout the colony, with 

 growing margin 2 to 4 mm. wide, white shading to court gray, then gnapha- 

 lium green (Ridgway, PI. XLVH) with the development of conidial struc- 

 tures and becoming mineral gray in age; exudate limited, pale amber; 

 odor lacking or indefinite ; reverse at first in golden yellow shades becoming 

 deep orange-brown near chestnut brown (R., PI. XIV) in 2 weeks; peni- 

 cilli abundantly produced, variable in size and complexity, strongly di- 

 varicate (fig. 84), borne either upon conidiophores arising from the sub- 

 stratum and varying in length up to 400 to 500/i by about 3.0 to 3.5/x 



