Shade Tkee and Timber Destkoying Fungi. 



239 



small amonnt of air in the interior of the tree. When sections of the 

 trunk were cut, and piled togetlier, the mycelium at the cut surfaces 

 grew very rapidly. The mycelium 

 here had access to air, and the moist- 

 ure was conserved by the cut sur- 

 faces being in contact. In this way 

 it was easy to demonstrate the 

 presence of the mycelium in parts of 

 tlio wood which to the eye appeared 

 sound. The mycelium grew out 

 from the wood into the moist air 

 along the concentric annual rings^ 

 and the medullary rays, so that 

 within 24 hours the location of the 

 mycelium at these points was plainly 

 demonstrated and photographs 

 taken at this time marked tlie location of the mycelium in 

 the infected areas. In several days' time, however, the myce- 

 lium spread out between the cut surface forming thin sheets of 

 " punk.'" 



POLYPORUS IgNIARIUS. 



This species occurs on broad leaved trees. It is known on the 

 apple, oak, alder, beech, birch, maple and other species. The fruit 



71. — PolypoTus igniarius, tongue 

 form of fruit body on beech. 



72. — Polyporus igniarius. Hoof form on beech. 



bodies are hoof-shaped, very hard, almost stony, the upper surface 

 black, while the lower surface, the fruiting surface, is brownish. 



