446 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



[Vol. 2 



to the young shoots. It has been positively determined that 

 the more effective tuber treatment is the standard corrosive 

 sublimate solution, as for potato scab. In all cases, however, 

 it would be better to employ seed which are not infected, if 

 this is possible. 



Conclusions and Notes 



In the account already given of RMzoctonia Crocorum per- 

 haps sufficient discussion of the occurrence and the character- 

 istics of this form has been entered upon, except in the way 

 of a direct comparison between this species and R. Solani, 

 subsequently included. Further work upon the first named 

 species should consider especially the culture of this organ- 

 ism, inoculation experiments, the development of the organ- 

 ism as it occurs on several hosts, the formation of sclorotia 

 and infection cushions, and the confirmation or more definite 

 declination of Eriksson's view that the fungus is referable 

 to Corticium (Hypochnus). From the study of this organism 

 thus far the following conclusions seem justified: 



1. The views of L. and C. Tulasne that the forms of Rhi- 

 zoctonia on crocus, alfalfa, and other hosts may be included in 

 a single morphological species is confirmed. 



2. The correct name of the violet root felt fungus, so long 

 as a spore stage remains uncertain, is RMzoctonia Crocorum 

 (Pers.) DC. 



3. This organism occurs throughout a considerable part 

 of Europe and has been found in a few localities in America. 



4. It attacks a variety of plants representing many fam- 

 ilies, mostly dicotyledonous. 



5. The mycelium and sclerotia exhibit no important dif- 

 ferences in equivalent stages on the different hosts, but large 

 sclerotia which form freely in contact with crocus, and often 

 near the affected roots of alfalfa, are seldom observed in con- 

 nection with the attacks upon beets, carrots, and some other 

 hosts. 



6. The existence of distinct forms or races of this species 

 reauires further extended studv. 





