MOXOVERTICILLATA 195 



more commonly from the aerial mycelium or from the basal felt, variable 

 in length up to 150 to 200/i by 1.8 to 2.5/x in diameter, mostly unbranched, 

 with walls delicately but conspicuously echinulate; penicilli strictly mono- 

 verticillate, generally small, with sterigmata in verticils of 4 to 6 or 8, 

 rarely more (Zaleski reported up to 20 or 25 upon neutral Raulin-gelatin) ; 

 sterigmata about 8 to lO/x by 1.8 to 2.2^, parallel, with conidium-bearing 

 tips definitely narrowed; conidia broadly elliptical to subglobose, mostly 

 2.5 to 3.3m in long axis, with walls conspicuously echinulate. 



Colonies on steep agar growing more rapidly, up to 4.5 to 5.0 cm. in 

 10 to 12 days, strongly wrinkled in a cerebriform manner, in texture as on 

 Czapek but somewhat heavier sporing (fig. 53E), becoming dull gray -green 

 in age; exudate limited, clear to pale yellowish; reverse as on Czapek but 

 developing dark shades less rapidly; conidiophores longer, commonly up 

 to 300 to 400m; penicilli somewhat larger and with conidia in adherent, 

 loosely parallel chains often forming irregular columns up to 100m or more 

 in length. 



Colonies on malt agar spreading, up to 5 cm. in 10 to 12 days, loose- 

 textured, almost floccose and 1 to 2 mm. deep, not furrowed or wrinkled, 

 reverse uncolored or in pale golden shades, medium sporing throughout, 

 conidiophores arising primarily from aerial hyphae, criss-crossed in the 

 manner of Penicillium spinulosum, commonly 200 to 300m or more in 

 length by 2.0 to 2.5m in diameter, with apices inflated up to 4.0 to 4.5m 

 and with walls conspicuously echinulate; sterigmata crowded, up to 10 

 or 12 in the verticil, otherwise as described on Czapek, bearing conidia in 

 loose columns up to 150m or more in length. 



Species description based primarily upon Zaleski's type, isolated from 

 forest soil in Poland. This culture received from the Centraalbureau in 

 1928 and now maintained as NRRL 731, was discussed by Thom in his 

 Monograph (1930, p. 189) as No. 5010.27. NRRL 2073, isolated from 

 lettuce seed and sent to us in January 1945 for diagnosis by J. Walton 

 Groves, Central Experimental Farm, Ottawa, Canada, is considered as 

 representing Penicillium trzebinskii but differs from the type in certain 

 details. Colonies are heavier sporing, develop less purple color in reverse, 

 penicilli are generally somewhat larger, and conidia are definitely ellip- 

 tical but less conspicuously echinulate than those of NRRL 731. 



Some additional cultures showing conidiophores and conidia echinulate 

 and reverse in purplish to violet shades have been encountered, and the 

 proper placement of Penicillium trzebinskii remains somewhat question- 

 able. It is placed with the P. lividum series, since it produces long, rough 

 conidiophores and echinulate conidia that are usually broadl}^ elliptical. 

 The over-all picture of the species, however, suggests close relationship to 

 P. spinulosum Thom and it is possible that the latter species should be 



