1921] 
MATSUMOTO—SPECIALIZATION IN RHIZOCTONIA à 
affinities of these could not be given with certainty. Subse- 
quently, Duggar and Stewart (’01) added a large number of 
hosts subject to Rhizoctonia attack and gave proof that the 
organism, or forms of the organism, exhibited morphologically 
and in culture the characters of the beet rot and damping-off 
fungus. Later, Duggar (15), after a most elaborate study of 
the common Rhizoctonia (designated R. Solani Kühn), made the 
following statement: ''In the different strains which have been 
studied, originating from different hosts, certain minor modifi- 
cations of the general habit of the fungus in culture have been 
observed. But these have not seemed to be sufficient to be 
considered of specific importance, except in the case of the form 
on the rhubarb.” Further, he said: “The subject needs fur- 
ther investigation, but in general it is felt that these differences 
are such as might be due to permanent differences in the patho- 
logical strains, on the one hand, or may be regarded as temporary 
differences due to the recent environment, on the other." Fur- 
thermore, in that paper he discussed more extensively the rela- 
tionship between the violet root felt fungus described by Tulasne 
as R. violacea and the common Rhizoctonia, and gave some of the 
important and easily observed contrasting features as usually 
found in these forms. He proposed that the first-named fungus 
should be designated as R. Crocorum (Pers.) DC., inasmuch as 
the more appropriate descriptive name, R. violacea Tul., does not, 
unfortunately, conform to the international rules of nomencla- 
ture. 
At about the same time Peltier (16), after a prolonged study 
of the common Rhizoctonia occurring in America, arrived at the 
conclusion that all strains studied by him could be included under 
one species, Rhizoctonia Solani Kühn, for no marked speciali- 
zation was noted in any of the strains. His argument is as fol- 
lows: ‘‘From these inoculation experiments with a large number 
of different types of plants we must conclude that all the strains 
studied, which were obtained from a wide range of hosts of 
diverse geographical origin, can attack the same species of plant 
and produce the same characteristic symptoms. No marked 
specialization was noted in any of the strains." From the cul- 
ture experiments he observed that the growth of the strains was 
very variable, those from the same host often producing a dif- 
