92 TREE WOUNDS AND DISEASES 



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

 times 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 of almost all colours from dull brown to 

 the brightest crimson, while beautifully spotted 

 and mottled kinds are not uncommon. Some 

 are valuable as food, others being utilised in 

 the making of tinder and razor strops. 



Healthy trees growing under normal con- 

 ditions are little affected by fungi, whereas 

 such as are predisposed to infection, by unsuit- 

 able soil, excessive drought or dampness, 

 injury by accident or otherwise in fact, 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, there- 

 fore, 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 



