FUNGI. 225 



variety depends, no doubt, on the way in which the 

 weight is supported. If dissected under a microscope, 

 it is found that the stalk is made up of many minute 

 fungus threads which pass up it, and then, turning 

 outwards, run into and terminate in the gills. Hence 

 the shape often resembles that of a sheaf of corn set 

 vertically upright. 



The part of the fungus which appears above the 

 ground is simply the spore-carrying body. The 

 threads, or mycelium, above-mentioned, pass from the 

 base of the stalk into the ground and branch out in 

 the soil of the wood. They are exceedingly thin and 

 almost impossible to distinguish by the naked eye, but 

 they are present in the soil of woods in enormous 

 numbers. They probably occur only in the upper 

 layers of the wood floor ; but, wherever leaves are 

 decaying, every square inch of the soil is thoroughly 

 explored by these fungus-threads, or mycelium. Hence 

 it is easy to see that they are of great importance to 

 the proper growth and development of the woods in 

 which they occur. 



Some fungi may be found upon decaying tree stumps. 

 The threa'ds or mycelium of these penetrate into the 

 rotting material and decompose it. They begin by 

 exploring the soft tissue under the cork, and between it 

 and the wood. They then pass in along the medullary 

 rays and break up the wood into a crumbling powdery 

 mass. The threads are able to pierce the cell-walls. 

 They can, in fact, excrete a special secretion which 

 dissolves the cell-walls, and they can, therefore, enter 

 every cell and absorb its organic matter. The wood- 

 powder remaining is then attacked by the Slime fufigi. 

 The dry-rot fungus {Merulius lachrymans), recognised 

 by the white, fluffy mycelium^ or the brownish, irregular, 



(B7) p 



