n.^^ TIMBER AND SOME OF ITS DISEASES [ch\p. 



there die off, the diseased parts shrivelling up rather 

 than rotting. 



If a diseased beech seedling is lifted, and thin 

 sections of the injured spots placed under the micro- 

 scope, it will be found that numerous slender colourless 

 fungus-filaments are running between the cells of the 

 tissues, branching and twisting in all directions Each 

 of these fungus-filaments is termed a hypha, and it 

 consists of a sort of fine cylindrical pipe with very 

 thin membranous walls, and filled with watery proto- 

 plasm. These hyphae possess the power of boring 

 their way in and between the cell-walls of the young 

 beech seedling, and of absoi'bing from the latter 

 certain of the contents of the cells. This is accom- 

 plished by the hyphae putting forth a number of 

 minute absorbing organs, like suckers, into the cells 

 of the seedling, and these take up substances from 

 the latter : this exhaustion process leads to the death 

 of the cells, and it is easy to see how the destruction 

 of the seedling results when thousands of these hyphae 

 are at work. 



At the outer parts of the diseased spots on the 

 cotyledons or leaves of the seedling, the above-named 

 hyph^ are seen to pass to the epidermis, and make 

 their way to the exterior : this they do either by pass- 

 ing out through the openings of the stomata, or by 



