BIVERTICILLATA-SYMMETRICA 597 



than a definitely specialized cellular wall. We believe the species should 

 be retained in the Biverticillata-Symmetrica where Swift originally as- 

 signed it upon the advice of Thom. 



PenicilUum avellaneum Thom and Turesson, in Mycologia 7: 284-287, figs. 

 1, 2. 1915. Thom, The Penicillia, pp. 446-447, fig. 70. 1930. 



Colonies upon Czapek's solution agar spreading broadly (fig. 154A), 

 up to 6.0 to 7.0 cm. in 12 to 14 days at room temperature, lanose to velvety, 

 becoming somewhat floccose in central colony areas, up to 2 mm. or more 

 deep, medium to light sporing throughout, heavier in marginal areas, ^vith 

 conidial areas becoming persistently avellaneous (Ridgway, PI. XL), in 

 new isolates characteristically producing perithecia slowly during a period 

 of several weeks accompanied by the gradual development of limited aerial 

 hyphae colored Indian red (R., PI. XXVII), in older stock cultures com- 

 monly failing to develop either perithecia or red hyphae; exudate limited, 

 in vinaceous shades; odor not pronounced; reverse in deep red shades near 

 Indian red, with agar similarly colored in lighter shades; conidiophores 

 arising primarily from the substratum up to 400m long by 3 to 5^ in diam- 

 eter, smooth-walled, terminated by conidial structures bearing tangled 

 chains of conidia up to 200m long; penicilli variable, typically compact, 

 consisting of a crowded terminal verticil of numerous metulae 8 to 10/x by 

 3 to 4m or more (fig. 143C), bearing verticils of 5 or more sterigmata 7.5 to 

 9.0m by about 2.0m, or with branches (metulae) more or less irregularly 

 disposed over the terminal 10 to 20m of the conidiophore; conidia ellipsoid 

 to almost globose, 3.0 to 4.0m or even 5.0m by 2.0 to 3.0m, smooth, often 

 appearing heavy- walled ; perithecia usually scantily produced, globose or 

 nearly so (fig. 154C), up to 400 or 500m in diameter, commonly smaller, 

 without a specialized cellular wall but bounded by an interwoven network 

 of mycelial elements, one or more cells thick, characteristically developing 

 asci throughout the central network of fertile hyphae, more or less brittle 

 in age; asci borne singly on short branches, ovate, about 12 to 15m by 9 to 

 10m, 8-spored; ascospores elHpsoid, 6.0 to 7.5m by 4.0 to 5.0m, ^^^th walls 

 thick, appearing double, pitted or with the appearance of round, trans- 

 parent spots (fig. 154D). 



Colonies on malt extract agar (Col. PI. IX) spreading broadly, 6 to 7 cm. 

 (fig. 154B) in most strains in 10 to 12 days; new isolates typically produce 

 abundant perithecia in bright yellow shades against a background of deep 

 reddish or reddish purple mycelium intermixed with light brown (avel- 

 laneous) conidial structures to produce a characteristic appearance; old 

 and usually non-ascosporic stocks are uniformly avellaneous throughout 

 from abundant conidial development; perithecia and conidial structures as 

 described above. 



