f 



404 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



[Vol. 2 



independent studies, one of a serious root disease of the sugar 

 beet, the other of a destructive stem rot of the carnation. A 

 preliminary report upon the investigations relating to R, So- 

 lani Kiilm was published ('01), and it was arranged that in 

 the further work one of us would undertake the morpho- 

 logical, cultural, and taxonomic aspects of the study, and 

 that the other would assume responsibility for all cross in- 

 oculation and field work. Unfortunately for this purpose a 

 change of position on the part of one of us and the demands of 

 other work necessitated the abandonment of the plan as pro- 

 posed. It is to be regretted particularly that the systematic 

 inoculation experiments which had been carried forward for 

 two seasons could not be continued and published. It is under- 

 stood, however, that an extensive study in the relations of the 

 culturable forms on different hosts has been carried forward 

 both by cultural and inoculation experiments at the University 

 of Illinois by Dr. George L. Peltier, who has already pre- 

 sented a preliminary report ( '15), on the subject. It is mainly 

 a general account of the diseases with notes on comparative 

 morphology that I am able to include, but it is hoped that 

 this may serve to clear up the more obvious difficulties and to 

 suggest some problems requiring special investigation. 



The writer wishes to acknowledge the assistance, mentioned 

 in the text, of many mycologists who have furnished material 

 during the progress of these studies, and especially the 

 cooperation of Mr. F. C. Stewart, who contributed many of 

 the American hosts during the earlier studies. To Prof. 

 E. A. Burt I am also indebted for suggestions. 



The Violet Root Felt Fungus, Rhizoctonta 



Crocorum (Pers.) DC. 



EARLY PATHOLOGICAL STUDIES 



The first mention of a plant disease which may be referred 

 with certainty to Rhizoctonia as the causal agent is an impor- 

 tant paper by Du Hamel: /17^>'jrjea;l before the Paris 



Academy. 



fungous dis 



In this paper he* "gives* a" careful description 

 isease of \CffhhUsl sattiuiis-'' (iakiJii) occurrir. 



of a 



' # (gaff .tan) occurring in 

 France. His description 'o? general' pathological features 



