[Vor. 8 
4 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
ferent type of growth even on the same media, and that the dif- 
ferences in various cultural characters which were shown by 
strains from unlike hosts were no greater than the differences 
which might be manifested by two different strains isolated from 
the same host, or by the same strain after being kept for different 
intervals of time in artificial cultures. He further stated that 
measurements of mycelial and sclerotial cells of the fungus 
showed large variations, not only between strains from different 
hosts but also between different strains from the same host; 
therefore no standard could be determined upon as a means of 
distinguishing the different strains. Duggar (16) concluded 
that the common seed-bed fungus in Germany and in France was 
identical with the damping-off fungus which had been frequently 
studied in the United States by Atkinson. Rosenbaum and 
Shapovalov (17) studied Rhizoctonia diseases of the potato in 
Maine and proposed a new strain of Rhizoctonia Solani Kühn 
based on the idea that the new strain might be distinguished 
from the more common Rhizoctonia (1) by the more pronounced 
lesions produced when inoculated into injured stems or tubers; 
(2) by the reaction, growth, and character of sclerotia on definite 
media; and (3) hy morphological characters, especially by the 
measurement of the short sclerotial cells of the mycelium; and 
lastly by the diameter of germ tubes. 
Ramsey (17), working on the form of potato tuber disease 
produced by these fungi, noticed two important phases of the 
inpry: In one of these the external appearance somewhat 
resembles scab and extends a dry core into the flesh of the tuber; 
in another the shrinkage of tissues forms a pit or canal in the 
center of the infected area, frequently suggesting wire worm 
injury. Concerning the form of the causal fungus, however, no 
adequate description was given. 
In the same year Matz (17) described a new species of Rhi- 
zoctonia on figs. According to him the sclerotia of this species are 
quite different from those of the common forms. "Therefore he 
proposed the name Rhizoctonia microsclerotia for this species. 
Concerning the studies on specialization of forms in the species 
here discussed, absolutely nothing has been reported, although 
the literature Parc with the specialization of other fungi is 
rather extensive; especially has the work been elaborate in 
