=Larch Disease.=—In all probability the larch disease or larch canker owes its origin to the minute spores formed in the fructification of the now well-known fungus—_Peziza Willkommii_. It has been pretty conclusively proved that these spores can only find a footing where the rind of the bark has become in some way injured, such as might be occasioned by the puncture of an insect, by wind, frost or from many other causes. The spores send down their germ tubes into the cambium, between the bark and the wood, where the moisture and nourishment afforded causes rapid development of the fungus. This soon spreads to the cells of the wood, and the annual layers either entirely cease to grow, or become disorganized and crippled in growth, causing a hollow appearance of the stem at the point of attack. The surrounding bark, by its attempts to heal over the wound, causes a thickened or burly appearance of the trunk, thus imparting to affected trees the cankered, swollen and distorted look that is so distinguished a characteristic. The disease appears in this country on the larch, both common and Tyrolese, at all stages of growth up to thirty years, but rarely after that age. I have examined a plantation of only four years’ growth sadly infested by the _Peziza_ whereas, in other cases, the trees may be fully twenty years old before being attacked. =Cause.=—Under what conditions of growth the larch is most susceptible to the _Peziza_ is still a matter of vague uncertainty, but there can be little doubt that an enfeebled constitution, as fully explained in the article on the larch “Trees for Economic Planting”, aided by our peculiarly erratic climate, has much to answer for. The variableness of our spring weather is, no doubt, one of the predisposing causes of disease, for, although no degree of frost experienced in this country can injure the tree when leafless, yet few are more sensitive when in young foliage. Bearing on the subject of the larch disease, I have communications from almost every part of the country, and have personally visited and examined many of the worst infested plantations, particularly in England and Wales. Soil, if we exclude peaty, would seem to have little or nothing to do with encouraging the disease, as I have found it equally virulent on dry, sandy and heavy damp soils, but worse on chalk. Curiously enough, the disease is hardly known in the peat bogs of Ireland, and there the rainfall is excessive. It is equally strange that it first made its appearance in the Eastern and drier parts of England, and gradually proceeded to the more humid West. I have, however, noticed it in certain low-lying still, and damp portions of some woodlands, and where frosts would be most prevalent, but such cases are not general.