Fungus Growth on Trees 215 



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. 



Remedy. Several remedies have been more or less 

 successfully tried with a view to getting rid of the disease 

 on trees, such as by cutting and scraping out the injured 

 portions, and applying a suitable dressing ; but such 

 remedies, although suited for single specimens, cannot be 

 applied to a whole area of infested trees. 



Under exceptionally favourable conditions, I have found 

 the larch to outgrow the disease, though the cankered, 

 swollen stems are never afterwards of great value for con- 

 structive purposes. Prevention in the present case is 

 undoubtedly the best measure, for when once it has made 

 headway, the larch disease is most, difficult to cope with. 

 By planting only sound, healthy trees, with uninjured 

 roots in the most suitable soils and situations, and retaining 

 these in as healthy a condition as possible, can we guard 

 against attacks of the disease. Hardwoods mixed with the 

 larch are to be recommended. 



Polyporus squamosus attacks the elm and other hard- 

 wooded trees and rapidly brings about decay. It is one 

 of our commonest species on diseased trees. 



The Sycamore Fungus (Rhytisma acerinum). Every 

 one interested in trees must be familiar with the conspicuous 

 black, pitch-like spots which so mar the appearance of 

 sycamore leaves. These are due to the above-named fungus 

 which, appearing as small yellowish spots on the under- 

 sides of the leaves towards the end of June, gradually 

 increase in size and intensity of colour until they attain to 

 fully half an inch in diameter and are inky black, with a 

 margin of dirty yellow. The attacked portion of the leaf 

 becomes wrinkled and much thickened in texture, while 



