244 A MANUAL OF THE ASPERGILLI 



resemblance to these forms in the comparatively light color of its conidial 

 heads and in the smallness and general character of its conidia, but differs 

 from these forms in three very striking particulars. (1) It character- 

 istically develops an extensive red-colored aerial mycelium upon media 

 such as malt-extract agar where it attains its maximum growth; (2) it grows 

 very sparsely upon Czapek's solution agar, upon which the above noted 

 forms grow luxuriantly; and (3) it possesses very small primary sterigmata, 

 measuring 5.5 to 6.5m by 2.4 to 2.8m in contrast to 13 to 15m by 3 to 5m for 

 mut. cinnamomeus and 15 to 40m by 4.6m for mut. Schiemanni. Whether 

 or not the species actually represents a naturally occuring mutation from 

 A. niger can only be guessed. The smallness of its conidia and primary 

 sterigmata would hardly support this hypothesis. In cases where mu- 

 tations have been obtained from known cultures, the dimension of specific 

 structures in such mutations generally agree very closely with those of the 

 same structures in the parent strain; and black Aspergilli with the dimen- 

 sions of A. panamensis are rarely, if ever, encountered in nature. The 

 possibility of this representing a mutation is not excluded, but until ad- 

 ditional evidence supporting such origin is forthcoming, the writers feel 

 warranted in maintaining as a distinct species this unique form which 

 obviously is able to maintain itself in the soils of Panama. 



The correct taxonomic position of this species remains in doubt. It is 

 included with Aspergillus wentii, although we realize that this placement 

 is not entirely satisfactory. As continued isolations are made from tropical 

 soils and other sources it is our hope that additional forms may be found, 

 which will furnish evidence of a more exact relationship. 



The very sparse development of A. panamensis upon Czapek's solution 

 agar, containing sucrose, results from an invertase deficiency; when dextrose 

 is substituted as a carbon source the fungus grows luxuriantly and fruits 

 abundantly. 



Aspergillus alliaceus Thom and Church, in The Aspergilli, p. 163. 1926. 

 Discussed without name as Thom No. 4660 by Walker and Lindegren, 

 in Jour. Agr. Res. 29: 507-514. 1924; and by Walker, Lindegren, and 

 Bachmann, in Jour. Agr. Res. 30: 175-187. 1925. 



Colonies on Czapek's solution agar rapidly and broadly spreading, with 

 loosely floccose aerial sterile mycelium, bearing scattered ochraceous 

 heads among abundant dark to almost black sclerotia (PI. VI D and fig. 66 

 A) in some strains, predominantly floccose with limited conidial heads and 

 few sclerotia in others (fig. 66 B); reverse uncolored. Conidial heads dull 

 yellow to ochraceous, strictly globose when young and remaining radiate 

 or splitting irregularly in age (fig. 66 D), up to 300m in diameter, often more 

 abundant in cultures after many transfers. Conidiophores up to 150m 



