THE LARCH. 231 
traced to a decayed post or stump, the remains of an old 
paling which had protected a cottar’s garden. The extremity 
of this root had been cut off in trenching the garden ground, 
which brought the wound on the root in immediate contact 
with the mycelium which overspread the decayed post, and 
to which the disease in the root and trunk of the larch was 
clearly traceable. 
The Larch Blister —This is a disease which appears on the 
stems or trunks of the tree, with a discharge of the sap, com- 
monly on one side of the trunk, while on the other side the 
ascent of the sap deprives the trunk of its regular shape, 
giving it sometimes a flat or a bulged appearance. It destroys 
the timber at the point of attack, which commonly extends to 
twelve or eighteen inches in length. I find it prevails toa 
very serious extent in many larch plantations throughout the 
country ; in others it is comparatively rare, such as in the 
larch plantations in my neighbourhood. My experience of 
this disease has therefore been very limited, and I cannot speak 
positively respecting its origin. I may state, however, that 
the plantations in which I have seen it most prevalent are 
situated either at a great altitude, or in places where frost is 
likely to fall heavily. Often finding a great uniformity in the 
position or height of the blisters on the respective trees, I am 
inclined to think that it arises from a severe frost in sum- 
mer, or while the tree is in a growing state, not sufficient 
to kill the shoot, but to interrupt the free circulation of the 
sap, and to form a weak point on the trunk. On examining 
the leading growth of a vigorous larch, the produce of a sum- 
mer in which a severe frost has occurred, the casualty is often 
indicated by an immature or weak point marking the length 
of the shoot at the time of the occurrence. A summer frost 
or blight sometimes marks very distinctly the vigorous shoots 
of the osier, forming a black spot or blemish, which in the 
operation of weaving occasions it to snap at the precise point, 
I expect the safety of the larch from this, as well as from 
other diseases to which the tree is subject, is to be found 
chiefly in having the plants of worthy extraction, the produce 
of trees which have been acclimatized to the country. 
