"^ BIVERTICILLATA-SYMMETRICA 591 



7.0/x in diameter, 8-spored; ascospores elliptical, spinulose over the entire 

 surface (fig. 151D), 3.0 to 3.om by 2.2 to 2.8m, colorless. Conidial struc- 

 tures limited in number, as described above. 



Colonies on cornmeal agar up to 4.0 to 4.5 cm. in two weeks, very thin, 

 vegetative mycelium submerged, perithecia fairly abundant in central 

 colony areas, thinning toward the margin, in form and texture as described 

 on malt agar, penicilli few in number, not affecting the colony appearance. 



Perithecial initials (fig. 144E) are easily recognized on cornmeal agar, 

 and, as described by Emmons (1935), usually appear as conspicuously 

 swollen and irregularh' branching sections of aerial hyphae. 



Species description centered upon numerous strains regarded as typical 

 of the species. Included among these are NRRL 1028, received in 1937 

 from C. W. Emmons; NRRL 1026 maintained in the Thom Collection 

 without change since 1919; NRRL 1029 received in 1939 from Professor 

 Leva B. Walker, University of Nebraska; and two cultures received from 

 the Centraalbureau under this name in the spring of 1946. In addition 

 to the above, six other strains recently isolated or received for identification 

 duplicate them in all essential characters. Strains examined have in- 

 cluded isolates from various stations in the United States and abroad. 

 The species is typically a soil form and appears to be widely distributed. 



In marked contrast to NRRL 1026, which has been maintained in cul- 

 ture for 28 years without losing its capacity to produce an ascosporic stage, 

 other strains have lost their capacity to produce perithecia in relatively 

 short periods of laboratory' cultivation. 



If examined superficially, this species might easily be mistaken for a 

 member of the Monoverticillata. Sterigmata commonly occur in simple 

 unbranched verticils and are often borne on relatively short conidiophores 

 that arise from trailing aerial hyphae. However, upon careful examina- 

 tion, the sterigmata are seen to be tapered in the manner typical of the 

 Biverticillata-Symmetrica, and the penicilli to range from simple mono- 

 verticillate, through irregularly asymmetrical to typical biverticillate and 

 symmetrical structures. Assignment in its present position is based upon 

 the character of its sterigmata and upon the maximal pattern of develop- 

 ment shown by its penicilli. The correctness of this placement is sub- 

 stantiated by the form, development, and character of its perithecium, 

 which lacks a definite specialized cellular wall, and by the pattern of the 

 ascospores produced. 



Pemcillium rotundum Raper and Fennell, in Alycologia, 40 : 

 518-521, fig. 4. 1948. 



Colonies on Czapek's solution agar growing very restrictedly (fig. 152A), 

 about 1.0 cm, in 2 weeks at room temperature, consisting of a compact, 

 fairly tough felt up to 500^ or more deep, at first appearing largely mycelial 



