1915] 



DUGGAR RHIZOCTONIA CROCORUM AND R. SOLANI 427 



gus, including its growth on culture media. It is clearly the 

 beet disease now well known in America, and of which the 

 causal fungus is referred to R. Solani. 



Kiihn did describe the symptoms of another disease of beets, 

 and this last bears every indication of being the heart rot later 

 known to be due to Phoma Betae (Phyllosticta tabifica), much 

 discussed by Frank and others. Kiihn 's discussion of this 

 other beet disease has been interpreted, also, in the way I 

 have indicated by Prillieux and Delacroix ('91) and others 

 outside of Germany. In my conference with him, Professor 

 Kiihn stated that the only Rhizoctonia diseases of beets and 

 carrots which he knew in the vicinity of Halle in 1858 and 

 earlier were those due to the violet fungus, and of these he 

 exhibited specimens having the usual characteristics. From 

 the evidence at hand, therefore, the Rhizoctonia disease of 

 beets described by Eidam was new on that host. It would 

 seem, then, that Eidam is the authority for the combination 

 R. Betae, which he attributes to Kiihn. In any case it be- 

 comes a synonym of R. Solani Kiihn (Corticium vagum 



B. & C). 



In discussing the Rhizoctonia disease of potatoes in Europe 

 Sorauer ('86) describes unmistakably the "black speck" or 

 sclerotial form of the fungus, and while he, like many others, 

 assumed that it would be found to belong among the Ascomy- 

 cetes, it is obvious that the characteristics of this stage of 

 Kiihn 's fungus were well recognized. 



Among the forms of Rhizoctonia which he enumerated and 

 discussed Comes ('91) includes R. Baud Kiihn, and R. Betae 

 Kiihn. In his discussion of the first-named he reviews Kiihn 's 

 account of the violet fungus on carrots, already mentioned; 

 but in the account of R. Betae Kiihn he evidently refers both 

 to Kiihn 's account of the heart rot of beets and to the Rhizoc- 

 tonia disease of this host described by Eidam. Pammel ( '91) 

 was the first American pathologist to report in this country a 

 disease now known to be caused by R. Solani. He, however, 

 followed Comes and Eidam in referring to the fungus causing 

 the beet rot as R. Betae Kiihn. 



Atkinson ('92, '95) studied a "sterile" fungus causing sore 



