WOODS AND FORESTS. 309 



and epidermis, and soon destroy the softer parts 

 between the nerves ; or, if the weather is wet, and 

 favourable to their development, Fungi begin to break 

 up the inner tissues, and only leave a sort of framework 

 of nerves and the more rigid parts. By the following 

 spring the Mosses run over the last year's leaf-fall ; and, 

 by their quickly formed and very efficient rhizoid or 

 root-hair system, further disorganise them. Next 

 September the remains of the leaves form part of the 

 food material of the Ground-fungi (see below). In sub- 

 sequent seasons they will still yield food to these fungi ; 

 but as they become covered by new leaf-falls they will 

 be also explored by the root-hairs and fungus-servants 

 {^Mycoi'hiza) of the Ferns, Garlic, Hyacinths, and other 

 plants. Eventually, every part of any value is turned 

 to account and enters the Mycorhiza of the trees, and 

 is utilised for the formation of new leaves and woody 

 material. During the whole of this gradual process of 

 decay, countless animals are at work. They burrow 

 about amongst the rotting material, and ensure a free 

 supply of oxygen, which is essential for the develop- 

 ment of the roots, and even for that of the ordinary 

 fungi. 



At every stage, also, bacteria come into action. The 

 dead fungi as well as dead animals and their droppings 

 are broken up by them. The ammonium-compounds 

 thus produced are, probably, converted by other bacteria 

 into nitrates. Some forms of fungi are even able to 

 utilise ammonium compounds directly. The history of 

 the sulphates and phosphates is still obscure ; but it is 

 most probable that bacteria or fungi are also essential 

 for their formation. 



The destruction of dead logs and branches is a very 

 lengthy process, and varies so much that it is difficult 



