IN DAMP AIR ONLY. 281 



aquatic plants adhere to the surface of submerged 

 timber, but they do so not for subsistence but for 

 stability ; and though the course of a ship through 

 the water may be impeded by the sea-weed on its 

 bottom, that weed does not tend in any way to 

 injure the timber. As there are no sea animals 

 which breed maggots in the dead bodies of land 

 animals that find their way to the sea, so there are 

 not in the sea any parasitical plants which hasten 

 the decay of land plants there. 



There is another proof in the peat bogs : when 

 trees fall through decay, in damp and rainy situa- 

 tions, and it is only in such situations that they 

 decay at the surface of the ground, there are 

 generally, if not always, successions of fungi around 

 the root of the tree for several years before it be- 

 comes so weakened as to yield to any thing but a 

 flood or a tempest. When the tree does fall it is 

 usually covered with fungi on those parts against 

 which the water forms a damp, but not where it 

 forms a pool. In that case, the fungi will be at the 

 surface of the water ; and if the trunk is altogether 

 under water there will be none. But even where 

 the fungi do appear, they are not of long conti- 

 nuance. Their soft glutinous substance, which is 

 soon gone in the ordinary seasonal crop, unites 

 with the mud which the rains of autumn, after the 

 season of the fungi is over, collect, and the two 

 form a water-tight paste by which the slope to- 

 ward the tree is converted into a little dam. There 

 are abundance of the germs of the fungi, in the 

 matter of these dams, although, in that stage, 

 even those of the larger species are not visible 

 until they have arrived at that period of their un- 

 derground growth, in which those of the esculent 

 B b 3 



