2ÖO 
ON A NEW CANKER-DISEASE OE PRUNUS YEDOENSIS. etc. 
or trunks throughout the year, if careful search is made. Although the effect 
of the disease on the general appearance of the tree is noticeable at any time 
during the growing season, it is most conspicuous during the spring months, 
at least in the vicinity of Sapporo, when the causal fungus is under most 
favorable conditions for its growth. 
In the vicinity of Sapporo, where the disease is common, it is not rare to 
find the entire tree or some of its branches which are in blossom or in leaf 
suddenly wither and then dry up at the beginning of May. The brown, 
shriveled flowers and leaves are readily seen even at a distance, while the 
healthy part of the tree is still in blossom or in foliage. If one examines the 
base of such a withered branch, a comparatively large canker or a part entire- 
ly girdled by the disease will be found. Such symptoms are also noticed in 
summer, although not numerous. If the point of infection is near the base 
of the trunk, as is most frequently the case, one side of the tree will wilt first, 
then a month or so later the rest of the tree. From the point of entrance, the 
fungus hyphae pass rather more slowly toward the center of the tree than 
they do up and down through the water ducts, causing the formation of a 
gummy substance, which plugs up the lumina of the ducts and cuts off the 
water supply for the transpiration organ of the tree. 
The wilted dead leaves or flowers remain clinging to the branches for a 
long time. If the plugging of the ducts by the gum or the girdling of a limb 
by the fungus takes place during the winter, the plant will appear in the 
spring as if it had been killed by a very low temperature. 
b. Appearance of the Diseased Portions of the Bark. 
On the smooth bark, by the death of the tissues of the cambium and 
inner bark, a canker formation takes place, accompanied generally by the 
exudation of gum around the affected portion. These cankered portions are 
slightly sunken, and distinguished from the healthy bark by a dark-brown or 
blackish-brown color, whereas the normal bark is more of a chestnut-brown or 
light-brown color. Often the bark on these cankered spots is more or less 
