SHADE TREK AND TIMBER DESTROYING FUNGI. 201 



thin smooth patches, or some forms are shelving, when the under- 

 side is smooth and is the fruiting surface. These belong to the 

 family Thelephoracea . A few of its members are very destructive 

 to wood and some are parasites on trees. In another family the 

 members are known as "coral fungi," or " fairy clubs " a large 

 number of them belonging to the well known genus Clavaria, 

 from which the family name Clavariacea is derived. The fruit- 

 ing surface is distributed all over the surface of the plant. To 

 a third family, Hydnacea belong the "hedgehog fungi," with 

 the fruiting surface on spines, a few species of which are well 

 known. A number of 

 the members of the two 

 last named families 

 grow on wood, but often 

 appear in late stages of 

 decay. A few species 

 like Hydnum septentri- 

 onale on maple, and H. 

 schiedermayeri on apple, 

 are destructive. 



The two largest fami- 

 lies are known as the 

 Agaricacece, to which the 

 common mushroom be- 

 longs, and the Polypor- 

 ace&. In the latter the 

 fruiting surface is in the 

 form of a honey-comb 57. Polyporus borealis, section of fruit body. 

 on the under side of the 



fruit body. It is to this last named family that the species belong 

 which are treated of here. 



The gross characters, those which are quite easily made out 

 without the aid of a mieroscope, are chiefly the ones presented 

 here, since a detailed account of microscopic structures and 

 changes brought about in the wood by the action of the 

 ingus, are rather too technical for full treatment in this paper. 



