BIVERTICILLATA -SYMMETRICA 563 



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bb. Conidia globose, conspicuously echinulate; reverse un- 

 colored or in pale drab to greenish shades, becoming dull 



l)ro\vn in age P. verruculosum Peyronel 621 



2'. Colonies usually more or less restricted upon most substrata, 

 aa. Conidia elliptical, heavy-walled, smooth; conidiophores 

 uncolored; colonies bristly, showing areas of red, orange, 

 or yellow mycelium and dark green conidia. 



P. islaiidicum Sopp 623 

 bb. Conidia ovate to elliptical, thin-walled, smooth; conidio- 

 phores heavy -walled, dull yellow-green; colonies fibrous 

 to floccose or floccose-funiculose, mostly in buff to orange- 

 pink shades P. varians Smith 625 



b. Conidial chains forming a conical or pyramidal mass; metulae 



numerous, incurved P. piceum Raper and Fennell 627 



2. Colonies with ropiness absent, or reduced and inconspicuous, typically 

 velvety or lanose; conidiophores arising primarily from the sub- 

 stratum or from the basal felt. 



a. Colonies on Czapek and steep agars usually developing an intense 



red or purple-red pigmentation; commonly producing aromatic 

 odors suggesting apples or walnuts on malt agar. 



P. purpurogenum series 631 

 1'. Colonies consistently producing deep red colors in reverse; 

 surface usually heavy sporing and showing an evident but 

 limited development of yellow or orange-red aerial hyphae. 

 aa. Conidia elliptical to subglobose; penicilli comparatively 

 long, sterigmata closely parallel ; pigmentation diffus- 

 ing throughout the surrounding agar. 

 1". Conidia typically roughened; colonies sometimes 

 spreading; conidial areas in dark yellow-green shades. 



P. purpurogenum Stoll 633 

 aaa. Producing sckrotia, at least when newly isolated. 



P. purpurogenum var. ruhri-sclerotium Thom 636 

 2". Conidia smooth; colonies more restricted; conidial areas 

 in lighter yellow-green to gray-green shades. 



P. ruhrum Stoll 637 

 bb. Conidia globose, echinulate; penicilli comparatively short; 

 sterigmata somewhat divergent; pigmentation seldom 

 diffusing throughout the surrounding agar. 



P. aculeatum Raper and Fennell 639 

 2'. Colonies developing red-orange, yellow-orange or greenish 

 brown rather than deep red colors in reverse; surface usually 

 characterized by prominent areas of sterile yellow aerial 

 mycelium P. variabile Sopp 642 



b. Colonics on Czapek and steep agars very restricted or thin, never 



developing an intense red pigmentation; reverse variously col- 

 ored in yellow to orange-brown, or greenish shades, sometimes 

 more or less mottled P. rugulosum series 646 



