ROOT-ROT OF CONIFERS 



183 



very thin, white felt of mycelium between the bark and the 

 wood, hyphae from which attack the wood. The contents 

 of the living cells change to a brown colour, and finally 



Fig. 41. Fomes annosiis. i, portion of fungus, half 

 nat. size ; 2, section of same, showing the stratified 

 tubes in three layers, nat. size ; 3, portion of hymeniurn 

 showing the tubes and their openings or pores, slightly 

 mag. 



almost disappear ; the wood next assumes a pale, yellowish- 

 brown colour with scattered white patches, each having 

 a black spot in the centre. Finally the cell-walls are 



