6o 



A TEXT-BOOK OF BOTANY. 



FlG. 35. A decaying tree trunk showing the cause of the death of the tree by the 

 appearance of the several fungi (probably Amanita muscaria). It is not unusual to find 

 trees showing signs of disease and, finally, even dying, and it is not until the death of the 

 tree that the mature fungus makes its appearance. For some years the mycelium of the 

 fungus has been working its way into the tissues not only of the bark but of the wood, 

 sapping it of its vitality. When there is no longer any food supply the fungus produces 

 its fruit; the spores, being scattered by either the wind or through the agency of birds, 

 are carried to other trees and find entrance into wounds, where they germinate and repeat 

 their destruction. From a photograph by Henry Troth. 



