THE ASPERGILLUS GLAUCUS GROUP 101 



posed the name Mucor herbariorum for the yellow perithecia found mixed 

 with the Aspergillus heads, which he regarded as a different mold. In 

 1809, Link designated the green heads Aspergillus glaucus and the yellow 

 perithecia Eurotium herbariorum. Half a century later, DeBary (1854) 

 proved that the Aspergillus heads and Eurotium perithecia were borne 

 upon the same mycelium, hence were one fungus. Although it could be 

 maintained that the name Eurotium (designating the perfect stage) should 

 take precedence over Aspergillus (descriptive of the conidial apparatus), 

 most recent authors have tended to go back to Micheli and use the name 

 Aspergillus for the whole group because of the obvious relationship of many 

 conidial forms for which no perithecia are known. 



Laboratory Cultivation 



The pattern and size of the ascospore, when present, is especially signifi- 

 cant in describing species of the Aspergillus glaucus group. Nevertheless, 

 the conidial apparatus and the vegetative mycelium of particular subgroups 

 are so important that pure culture under known conditions is always de- 

 sirable. The character of the colony, as well as the amount of growth, is 

 strongly influenced by the culture medium, and it is only upon substrata 

 characterized by a high osmotic tension that typical perithecia and conidial 

 heads are produced. It should be noted, however, that characteristic 

 heads and perithecia normally develop, although few in number, in situa- 

 tions where less concentrated media dry out rapidly, as at the edge of an 

 agar slant. Colony comparisons for correct identification can best be 

 made in Petri-dish cultures in which direct observation with the compound 

 microscope is feasible. Incubation at 22° to 25° C. will permit the develop- 

 ment of satisfactory colonies for descriptive study, although the optimum 

 for certain species is above or below this range as will be noted in connection 

 with these descriptions and in the general discussion on the influence of 

 temperature on colony growth and development in the genus (p. 45). 

 Colony descriptions are based upon 3-week old cultures, except as otherwise 

 stated. For comparative culture the authors have followed Dale (1909) 

 in using substrata containing high concentrations of sugar. The following 

 formula is recommended : 



Czapek's solution agar with 20 percent of sucrose 



Sodium nitrate 3 gm. 



Dibasic potassium phosphate 1 gm. 



Magnesium sulfate 0.5 gm. 



Potassium chloride 0.5 gm. 



Ferrous sulfate 0.01 gm. 



Sucrose 200 gm. 



Agar 15.0 gm. 



Dist. water 1,000 cc. 



