TREES AND SHRUBS 



Birch-leaf Blotch, Dothidella betulina, appears as small hlotches containing 

 white cavities or cells in which the fruit of the fungus is developed after 

 the leaves have fallen to the ground. The asci enclose eight sporidia. 



Birch Polypore, Polyparus betuUnus, is a hoof-shaped fungus often found 

 on dead Birch-trees, and sometimes attacking and destroying living trees. It 

 measures .*5-8 ins. across, and is soft and whitish when young, becoming firmer 

 and brown with age. The mycelium is probably perennial, so there is no 

 hope of saving a tree when once attacked. To prevent the dispersion of 

 spores, all specimens of the fungus should be destroyed. 



Crack Willow Bust, Melamspora epitea, is found on the foliage of several 

 species of Salix, in the form of minute orange powdery pustules. The 

 globose uredospores are pale yellow, and the cylindrical teleutospores are 

 at first brown, then nearly black. Both are present on the underside of 

 the leaf. 



Conifer Boot Bot, Trametes radiciperda, is the most dangerous of all the 

 parasites met with in coniferous woods. It attacks Scots Fir, Weymouth 

 Pine, Norway Spruce Fir, Silver Fir, and other conifers, causing the worst 

 form of red-rot. The mycelium forms a felted mass between the bark-scales 

 of the roots, scarcely as thick as the finest tissue-paper, and the sporophores 

 appear as small cushion-like structures, coalescing to form a thin white cake, 

 usually 1-2 ins. in diameter, but sometimes measuring as much as 16 ins. 

 across. The spores may possibly be disseminated by mice or other burrowing 

 animals, but usually the disease spreads by means of the mycelium travelling 

 from a diseased root to any sound root which may be in contact. Having 

 gained an entrance between the bark-scales of the root, the mycelium finds 

 its way into the wood and travels up the stem, causing decomposition of 

 the tissues, and the ultimate death of the tree. All diseased trees should 

 be removed, great care being exercised to take from the ground every portion 

 of the old stump and diseased roots. 



Elm-leaf Phloeospore, Phleosporu Uhni, is one of the commonest parasites 



on Elm leaves, sometimes attacking nearly every leaf on a tree. The small 



brownish spots are dotted with pustules from which there exude whitish threads 



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