DESCRIPTION OF PLATES. 



PLATE I. Frontispiece. A tree of aspen (Populus tremuloides) bearing several sporo- 

 phores of Fomes igniarius. The tree is badly rotted within, and the fungus has 

 formed its fruiting bodies at old knot holes left by the dying of small lateral 

 branches. The tree is still alive, but is sure to die within a few years. 



PLATE II. Effect of Fomes igniarius upon living trees. Fig. 1. Cross section of the 

 trunk of a tree of silver maple (Acer saccharinum) which bore but one fruiting 

 body, this being the only external indication of disease. Note the black, narrow 

 zones surrounding the completely decayed wood; also the place of entrance at 

 the upper right-hand corner produced by the rotting of a dead lateral branch. 

 Fig. 2. Cross section of a living tree of aspen badly diseased with the white 

 heart-rot. Note concentric, dark zones surrounding the diseased part. 



PLATE III. Decay of living trees caused by wound fungi. Fig. 1. Cross section of 

 a living tree of beech (Fagus atropunicea) decayed by Fomes igniarius. This 

 tree bore but a single fruiting body, this being the only external indication of 

 disease. The decay extended about 4 feet both upward and downward from 

 the sporophore. Fig. 2. Cross section of the trunk of a living red oak (Quercus 

 rubra) rotted by Fomes everhartii. 



PLATE IV. Polyporus sulphureus. Fig. 1. A large compound fruiting body of 

 Polyporus sulphureus, such as is very often found. Fig. 2. Cross section of the 

 trunk of a living tree of post oak (Quercus minor) rotted by Polyporus sulphureus. 



PLATE V. Piped-rot. Fig. 1. Longitudinal section of the trunk of a living tree of 

 black jack oak showing the piped-rot. Fig. 2. A piece of chestnut wood dis- 

 eased with the piped-rot. 



PLATE VI. Fomes nigricans. Fig. 1. Cross section of the trunk of a living tree of 

 paper birch (Betula papyrifera) diseased by Fomes nigricans. Fig. 2. The trunk 

 of a paper birch (Betula papyrifera) showing an irregular aborted sporophore of 

 Fomes nigricans growing at an old wound. 



PLATE VII. Hydnum erinaceus. Fig. 1. Cross section of the trunk of a living tree 

 of white oak (Quercus alba) with the heartwood rotted by this fungus. Note below, 

 at the left, two burrows of the oak borer through which this fungus probably 

 entered. Fig. 2. Fruiting body of Hydnum erinaceus growing in a hollow oak 

 trunk. 



PLATE VIII. Fomes fomentarius . Fig. 1. Sporophores growing upon a dead tree of 

 beech (Fagus atropunicea). Fig. 2. Cross section of the trunk of a dead beech 

 tree with the sapwood rotted by this fungus; the heartwood is practically sound. 



PLATE IX. Polyporus betulinus. Fig. 1. A dead trunk of yellow birch (Betula lutea) 

 with a large sporophore of Polyporus betulinus. This fruiting body measured 

 about 1 foot in diameter. Fig. 2. Cross section of the trunk of a dead yellow 

 birch tree with a fruiting body of Polyporus betulinus. The wood is entirely 

 rotted. 



PLATE X. Daedalea quercina. Fig. 1. An oak railroad tie with fruiting bodies of 

 Jiaedalca quercina. The tie is badly decayed within. Fig. 2. A section of the 

 above tie 2 feet from the end bearing the fruiting bodies of the fungus. It will 

 be noted that in the lower part it is quite seriously affected. 



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