ASYMMETEICA-VELUTINA 413 



Colonies upon steep agar attaining a diameter of 3.5 to 4.0 cm. in 12 to 

 14 days at room temperature, but usually similar to the above in basic 

 pattern and coloration, sometimes narrowly zonate, often heavier sporing; 

 microscopic details of penicilli as described above. 



Colonies upon malt extract agar attaining a diameter of 3.0 to 3.5 cm. 

 in 12 to 14 days at room temperature, plane, velvety (fig. 107D), often 

 becoming more or less zonate in marginal areas after 12 to 14 days; details 

 of microscopic structure as above. 



Species descr ption based primarily upon the following strains: The type, 

 XRRL 859 (Thom No. 27), isolated by Thom from a rotting mushroom 

 in the summer of 1904 at Storrs, Connecticut, and maintained continuously 

 in culture since that time without apparent change in colony appearance 

 or details of structure; NRRL 860 (Thom No. 79) isolated by Thom in 1908 

 from maple sugar at Storrs; three cultures received from the Centraalbureau 

 under this name in May 1946; a strain received from the same source as 

 Penicillium biourgeiarium Zaleski (see below) and numerous other strains 

 examined during the current study and in previous years. 



^Marked variation is regularly encountered among strains regarded by 

 us as representing Penicillium stolonifcrum Thom. Other workers have 

 considered individual isolates sufficiently distinctive to warrant species 

 status, and have so described them under other names. However, when 

 large numbers of strains are examined in parallel cultures, as in the present 

 work, many of the assumed distinctions disappear and the validity of these 

 species becomes questionable. Described species that are believed to 

 approximate P. stoloniferum Thom include the following: 



Penicillium griseo-brunnenm Dierckx (Soc. Scien. Brux. 25: 88. 1901. In Bi- 

 ourge Moiiogr., La Cellule 33: fasc. 1, pp. 162-163; Col. PI. II and PI. Ill, fig. 19. 

 1923; Thom, The Penicillia, p. 302. 19.30) was reported by Biourge in terms which 

 indicated close relationship to P. stoloniferum Thom. Thorn's culture notes (1930) 

 on a strain presumed to be type, failed to show differences adequate to separate 

 Dierckx's species from P. stoloniferum. Strains received from the Centraalbureau 

 and from George Smith under this name and included in the present stud}', differ from 

 the type of P. stoloniferum only in producing somewhat faster growing colonies with 

 marginal areas on Czapek's agar thin and somewhat submerged. 



Penicillium erectum Bainier, (Bui. Soc. Mycol. France 23: 13, PI. Ill, tigs. 1-16. 

 1907; Thom, The Penicillia, p. 295. 1930) is known only from the author's original 

 description. Conidiophores were reported as long, unbranched, about 5.6ai in diam- 

 eter and to bear penicilli with one or two series of branches in 1-sided verticils sur- 

 mounted by verticils of metulae and sterigmata. The description and figures in- 

 dicate some member of the P. hrevi-compactum series, probably approximating P. 

 stoloniferum Thom. 



Penicillium tabascens Westling (Arkiv for Botanik 11: pp. 56, 100-102; figs. 20, 61. 

 1911 ; Thom, The Penicillia, pp. 300-301. 1930) as known by a culture received from 



