134 A MANUAL OF THE ASPERGILLI 



produced more abundantly at 12° to 15° C. than at room temperature; 

 conidiophores colorless to brown, mostly 250 to 35(V in length, enlarging 

 to 15 to 20ju below the vesicle; vesicle subglobose, mostly 30 to 40/i in 

 diameter; sterigmata in a single series, crowded, short, 7 to 8/t by 4 to 5/x; 

 conidia green, globose to subglobose, finely echinulate, thick-walled, mostly 

 8 to 10/x in diameter, but frequently larger or smaller. 



Represented in the NRRL collection by culture No. 124 which was re- 

 ceived in 1924 from Raistrick, who in turn received it from the Centraal- 

 bureau. It is believed to be Meissner's original strain (1897). Subcultures 

 of this strain are currently maintained at Baarn and by George Smith in 

 London. The three lines remain identical as shown by parallel cultures 

 during recent study. 



This fungus is distinguished particularly by (1) its very slow growth 

 upon 20-percent sucrose Czapek agar at room temperature, (2) its tardiness 

 in producing perithecia and especially in ripening ascospores, (3) its sparse 

 production of ascospores, and (4) its formation of aerial hyphal bundles 

 bearing conidial heads in loose coremiform fashion. Further, it grows 

 much more rapidly upon Czapek agar containing 40 percent of sucrose than 

 upon that containing 20 percent, a difference in concentration which does 

 not materially affect the growth rate of such vigorous species as A. repens 

 and A. chevalieri. Growth is much more rapid at 20° C. than at 28° to 

 30° C. (fig. 12). The fungus attains a more favorable form at the lower 

 temperature, at which there is a heavier growth of mycelium, a more 

 extensive development of aerial hyphal columns, and a greater production 

 of conidial heads and perithecia. 



Culturally this fungus is easily separated. from all other species of the 

 group, except possibly A. carnoyi. 



Aspergillus carnoyi (Biourge) Thorn and Raper, IT. S. Dept. Agr. Misc. 



Pub. 42G, p. 34. 1941. 



Colonies upon Czapek's solution agar (3 percent sucrose) very restricted 

 reaching a diameter of only 3 to 4 mm. in 6 to 8 weeks, thin, white, bearing 

 neither conidial heads nor perithecia; reverse colorless. 



Colonies upon Czapek's solution agar with 20 percent of sucrose at room 

 temperature extremely slow growing (optimum 18° to 20° C), reaching 

 a diameter of 7 to 8 cm. in 6 to 8 weeks, irregular in outline, somewhat 

 floccose, forming a deep felt, bearing abundant perithecia and scattered 

 conidial heads (fig. 33 F), orange-brown in central area to orange at margin 

 from abundant perithecia in a loose network of sterile hyphae encrusted 

 with orange-red granules; reverse in orange-red shades. 



Perithecia late in developing, abundant, yellow to orange, globose to 

 subglobose, mostly 125 to 175/* in diameter but frequently larger or smaller, 

 borne in a loose floccose felt of sterile brown hyphae; asci 16 to 18ju, 



