2 



Mycologia 



oder mit einer einheitlichen Konidie zu tun haben. . . . Diese 

 Schwierigkeiten konnten nur durch eine genaue Untersuchung 

 der Konidienbildung und -teilung behoben werden." 



The mycelium of this organism develops readily in a variety of 

 media, most luxuriantly in those containing dextrose. Mannite 

 N free agar, dextrose, starch and mannite N free nutrient solu- 

 tions, solidified blood serum, dextrose and peptone gelatin, and 

 peptone solutions all support good growths. The hyphae are 

 much branched, and cross and recross in every direction. For 

 the most part, they remain near the surface of the medium, the 

 organism being a strict aerobe. The hyphae vary considerably in 

 diameter, from 3 to 8/x. They are septate and usually granular. 

 The mycelial threads lying in the medium are hyaline and color- 

 less, at least when young; from them is diffused a pigment, which 

 is brown in dextrose and lemon-yellow and later brown in mannite 

 media. This pigment is soluble in alcohol and in water. Aerial 

 hyphae are developed in considerable numbers. In the absence 

 of an excess of moisture, these produce the sporodochia and the 

 spores ; in a saturated atmosphere, they form pink or brown 

 masses of hyphae several millimeters in diameter. The hyphae 

 lying in the medium show marked antibiosis toward the hyphae 

 of certain species of Penicillium and some other molds. 



The sporodochia arise from the aerial hyphae. Certain threads 

 branch and rebranch to form a dense mass, or sporodochium, 

 from which the conidiophores develop. The tips of the latter 

 become fuscous and swell to form the spores. The conidio- 

 phores are from 5 to 25 ^ in length, and septate when long. The 

 spore is not readily broken off. These sporodochia are usually 

 spherical or ovoid and vary in diameter when mature from 50 

 to 500 /x. The young sporodochia may be early recognized by the 

 fuscous tips of the branches of the aerial hyphae. 



The sporodochia and spores are not developed readily in a 

 saturated atmosphere. A thick layer of agar, for example, in the 

 bottom of a Petri dish will prevent the formation of spores, 

 although under these conditions there may be an abundant pro- 

 duction of aerial hyphae. If the cover of such a plate be re- 

 moved and the surface of the medium allowed to dry somewhat, 



