[Vol. 2 



428 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



shin or clamping off in cotton, and ascertained that the same 

 fungus was commonly associated with, and capable of, induc- 

 ing damping off of various seedlings in the greenhouse. 



Duggar ('99) also referred to the beet rot fungus in Amer- 

 ica as Rhizoctonia Betae Kiilm, following Comes, and was 

 able to determine that this beet fungus was identical morpho- 

 logically (mycelium and sclerotia) with the damping off fun- 

 gus found by Atkinson. The characteristics of the two organ- 

 isms in culture were also identical, both forming on certain 

 media a rich mycelium and finally numerous flaky or tufted 

 centers of growth, some of which become irregular, often 

 crust-like, sclerotia. Neither on affected seedlings nor on 

 beets were sclerotia ordinarily produced (compare, however, 

 Edson, '15, pi. 23). 



Subsequently, Duggar and Stewart ('01) reported that 

 several types of disease, on a variety of hosts, including the 

 potato, were induced by Rhizoctonia, The account given was 

 intended to be merely preliminary, and for this reason a few 

 words of explanation are necessary. The account referred to 

 did not (perhaps unfortunately) explicitly indicate that, as 

 far as the studies had progressed, there was evidence that 

 the organism, or forms of the organism (except in the case 

 of the form on rhubarb, referred to later) exhibited morpho- 

 logically and in culture the characters of the beet rot and 

 damping off fungus. The authors were likewise convince ' 

 after a study of European material of Kiihn 's fungus on the 

 potato, of the identity of the American and European forms 

 on this host. Cultural studies were being carried forward 

 with Rhizoctonia Solani from many hosts, since there was 

 the possibility of establishing definite forms or races, of find- 



d 



the perfect stage, and of disco\ 



A 



specimens of the violet root felt fungus on various hosts had 

 been obtained by one of us, and it was intended to include 



final paper a general account of 



rt 



This failure to designate the form with which we worked 

 has doubtless led to some misunderstanding (see Prillieux 

 '97, Eriksson '13, p. 17). However, in a more recent account 

 (Duggar, '09, pp. 477-478), it will be seen that the diseases 



