ca 
170 BOTANICAL GAZETTE [AUGUST 
root-felt fungus found on crocus, alfalfa, and many other hosts (of which 54 
are listed by him) belong to a single species, to which the name Rhizoctonia 
crocorum (Pers.) DC. must be applied as long as the fruiting stage remains 
unknown. This view is based upon a critical examination of the data in the 
literature and an extensive study of living material and herbarium specimens. 
He regards the evidence thus far presented as insufficient for the identification 
of the perfect stage of the fungus. Unlike Errxsson, he finds no resemblance 
between the mycelium cached by spores of Leptosphaeria circinans which 
he germinated and the hyphae of R. crocorum. Duccar further gives an 
account of Rhizoctonia Solani Kiihn, which is the more common of the two 
species in America where it is the widespread cause of “damping off” of 
seedlings and cuttings and root-rot of various crops. This species is clearly 
differentiated from the violet Rhizoctonia by characteristics of the mycelium 
and the sclerotia, as well as by the effects produced on the host plants. Fur- 
thermore, evidence seems to be sufficient that the perfect stage of this organ- 
ism is Corticium vagum B. and C. In a later paper,‘ as a result of a study 
of the data in the literature, this fungus is identified with the “‘ Vermehrungs- 
pilz” common in the seed beds and cutting beds of Germany and France, and 
also with the ‘ Mopopilz,” causing considerable damage to the seed beds of 
cinchona in Java. The failure to recognize Rhizoctonia Solani as the general 
cause of the “damping off” of seedlings in Germany and France, as well as 
in Java, is attributable to wrong determinations of the European seed bed 
fungus and the cinchona fungus of Java. 
g diff, i by D between Rhi ton is Sean 
2 ye * Soe Pt, ae an 
i a ee es while R. 
: _ crocorum had not, up to that time, been successfully grown. Recently, 
however, DreHts reports successful cultures of the fungus from detached 
_ masses of mycelium. he cg lgishome plone aurea 
instance was a pure culture 0 
® 
on 
of th ic Rhizoctonias of the 
United States eek ee The chief features of the — 
report are (x) a general historical account, (2) a discussion of the oe so 
= 1 a the data relating to the hosts, occur ce 
rence, and distribution of R. Solani and R. 
ie ne tin i ome other countries, OTe a 
1 e induce by these fungi in different plants, (3) eke calle a 
aa “Deccan, 2 B. Me Rhisctonia ‘Solani in teladion to the “Mopopile” and mae ’ 
Verm eh Sp 
a 916. os 
e of | ee ES tee 
