TA ICE WO HEMMI 
26 I 
cracked at the marginal portion. These cankers occur on branches of all 
sizes, — rarely, however, on young branches. The usual shape of the canker 
is elliptical, being longer in the direction of the long axis of the branch. 
The margin of the canker is usually fairly regular, but it may be irregular. 
According to my observations, the cankers formed on the large branch be- 
come deeper year by year as healthy wood is formed about them, thus causing 
a condition similar to the apple-tree canker or the American chestnut-tree 
canker. When the fungus affects the rough bark of the trunks, the cankers 
do not show very distinctly, since the change in color of the bark is not 
evident and the shape of the canker is mostly irregular. It is frequently 
distinguished from the healthy parts only by the lenticel-like openings of the 
stromata. But the cankers on the rapidly growing branches are usually out- 
lined by a distinct ridge of slightly hypertrophied tissue. It seems to me 
that there are two different types of the diseased branches. The one is the 
cankered type (PI. VII, Fig. 2-4) as already described, and the other is the 
girdled type (PI. VIII, Fig. 1) which does not produce the canker. The latter 
takes place mostly in the case of the weakened trees or when the rather fine 
branches or twigs are infected in spring. The girdling is caused by the rapid 
growth of the mycelium without inducing the formation of a definite canker; 
and the fruiting pustules break out rather scatteringly all over their surface. 
Such a diseased portion extends sometimes to the greater part of the branch, 
which at once withers and dies. Although this girdling is seen more or less 
on all host plants, it is most common on Prunus sackalinensis Koidz. (PI. 
VIII, Fig. 1), which is rarely attacked by this disease and on which I have 
not yet found the cankered type. 
The fruiting pustules are at first covered by the periderm, which becomes 
lifted up and finally ruptured, exposing the brown or blackish brown stromata 
of the fungus. These slits appear at first glance like the lenticels, for they 
are usually elongated horizontally. During the growing season, when the 
weather is damp, from these pustules are pushed out very fine reddish threads 
or spore-horns which are composed of innumerable pyenospores. In the 
