276 TIMBER AND SOME OF ITS DISEASES. [CHAP. 



there die off, the diseased parts shrivelling up rather 

 than rotting. 



If a diseased beech seedling is lifted, and tl 

 sections of the injured spots placed under the mici 

 scope, it will be found that numerous slender colourh 

 fungus-filaments are running between the cells of tl 

 tissues, branching and twisting in all directions. Ea< 

 of these fungus-filaments is termed a hypha, and 

 consists of a sort of fine cylindrical pipe with vei 

 thin membranous walls, and filled with watery protc 

 plasm. These hyphae possess the power of boring 

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

 beech seedling, and of absorbing from the lat 

 certain of the contents of the cells. This is accoi 

 plished by the hyphae putting forth . a number 

 minute absorbing organs, like suckers, into the ce] 

 of the seedling, and these take up substances froi 

 the latter : this exhaustion process leads to the deat 

 of the cells, and it is easy to see how the destructi< 

 of the seedling results when thousands of these hypl 

 are at work. 



At the outer parts of the diseased spots on the 

 cotyledons or leaves of the seedling, the above-named 

 hyphae 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 



