STEREUM WOOD-ROT 



175 



frequently, however, the uppermost portion of the thin flap 

 is free from the wood, and spreads at right angles to the 

 fixed portion. The upper surface of the free portion is 

 coarsely velvety, at first dingy yellow, and marked with 



Fig, 38. — Siereum hirsidum. i, fungus about half nat. 

 size ; 2, section through same ; 3, basidia, bearing four spores 

 each, X 350. 



concentric zones, becoming grey or whitish when old. The 

 margin is often wavy or crisped. The under surface, which 

 is the hymenium, is smooth, and of a clear ochraceous buff 



