TAK.EWO HEMMI 303 
fungus stromata on the bark. Its appearance on the ist of May is shown in 
the photograph of PI. VIII, Fig. 2. In the sixth case, the upper twigs wilted 
about the middle of May, and the pustules of the stromata began to be pro- 
duced at the end of the same month. 
Experiments VII. 
In April, 191 5, several inoculation experiments were made with myce- 
lium from cultures, isolated from various host plants, on the burned bark 
of the seedlings of P. yedoensis. The results of these experiments are as 
follows : — 
Table XIV. 
Host of inoculated fungus 
Time of 
inoculation 
Results 
Prunus Fersica S. et Z. 
April 9 
On May 10 the uppermost shout wilted and 
on about June 4 the stromata developed. 
Prunus sachalinensis Koidz. 
April 9 
On May 3 the uppermost shoot wilted and 
at the end of May stromata developed. 
Prunus Mume S. et Z. 
April 30 
Negative 
Prunus Cerasus L. 
April 16 
Negativ e 
Prunus yedoensis Matsum. 
April 9 
On May 1 the uppermost two shoots wilted 
and at the end of May stromata developed. 
14. Entrances and Promoting Agencies of the Disease. 
Judging from the results of the inoculation experiments, we may safely 
infer that Valsa japonica is the direct cause of this canker-disease, and that 
the fungus is a wound parasite requiring for its infection various kinds of 
wounds. When the spores germinate in a wound, the -mycelium derived 
from the germ tubes thrives on the injured and dead cells until it has produced 
a mass of mycelium. Then, gradually accumulating strength as it increases, 
the mycelium en masse pushes out into the living tissue of the bark. Single 
hyphae do not seem to possess the power of penetrating into the living cells, 
but the invasion is accomplished by the force of mass action. Starting from 
