CHAPTER XXII 

 FUNGUS GROWTH ON TREES 



SOME fungi attack living wood, some dead, and some both ; 

 and, while the majority are found growing on the stem, 

 others attack the twigs, leaves or root. They are of all 

 sizes, from the almost microscopical to the beefsteak fungus, 

 which often exceeds a couple of feet in diameter. Some are 

 jelly-like in consistency, others leathery or almost woody 

 in texture ; and while certain kinds spring up and disap- 

 pear in a few days, others remain intact on the tree stem 

 for several years. In shape, too, they vary considerably, 

 from the curious Jew's ear fungus, which greatly resembles 

 the human organ, to the giant puff-ball, that sometimes 

 measures four feet in circumference. Then the cup-shaped 

 and parasol fungi are appropriately named, while the flat, 

 shelf-like arrangement of a species that frequents the oak 

 and elm has interested many a casual observer. Excepting 

 perhaps green, they are found of almost all colours from 

 dull brown to the brightest crimson, while beautifully 

 spotted and mottled kinds are not uncommon. 



Healthy trees growing under normal conditions are little 

 affected by fungi, whereas such as are predisposed to infec- 

 tion, by unsuitable soil, excessive drought or dampness, 

 injury by accident or otherwise in fact, those in a weakened 

 condition however brought about are, of course, far more 

 liable to attacks. Though certain species of fungi only 

 attack dead and decomposing wood, and are, therefore, the 

 consequence and not the cause of disease, there are others, 

 fortunately fewer in number, that attack healthy living 

 trees and are the direct cause of disease and death. The 

 prevention and extermination of fungus pests is by no 



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