June *8,1917 
Rhizoctonia solani on Potato 
4i7 
a smaller diameter. It was not possible to obtain a culture from a single 
basidiospore, but dilution plates were made and a culture obtained from 
the germination of a single short typical sclerotial cell. This culture 
Fig. a.—Camera-ludda drawings of short sclerotial cells of the Ri and Rj strains from 
cultures of the same age grown on the same medium. 
agreed in all essential characters previously enumerated with the other 
cultures of R5. 
While the mycelium measurements of R5 and all the remaining strains 
with which the writers worked are distinct, they do show variation, as 
indicated by the measure¬ 
ments given above. There 
may also be a question as to 
the accuracy of random 
measuring, even from 
mounts made from the same 
medium of the same age. 
A more accurate manner of 
identification of R5 from 
the remaining strains con¬ 
sists in the germination of 
the short sclerotial cells in 
water and the measure¬ 
ment of the diameter of the 
germ tubes produced. The 
mode of germination of the 
short sclerotial cells of R5 
agreed in all essential characters with that of the remaining strains and 
has been described by Duggar 1 and others. Measurements made of the 
diameter of the germ tubes produced by R5 and the remaining strains 
Fig. 3.—Camera-ludda drawings of germinating sclerotial cells 
of the R7 and R5 strains. The drawing was made at the end 
of 17 hours, after the cells were placed to germinate in drops of 
water. 
1 Duggar. B. M. Op. dt. 
