CHAPTEE VIII 



SAPROPHYTES AND PARASITES 



The student will not proceed far in the investigation of the 

 nature and relations of Fungi before he is called upon to 

 recognise the distinctions between saprophytes and parasites — 

 the species which thrive upon the decay and cause the dis- 

 integration of dead matter, and those which infest and flourish 

 upon the tissues of living plants. Saprophytes are numerically 

 in preponderance throughout the Fungi as a whole, and represent 

 those forces of rejuvenescence which build up from the ruins 

 of an old life the forms of a new generation. They are not 

 only the agents in disintegration, but the immediate con- 

 sequences of the phenomena of decay. Dead wood, leaves, 

 fruits, herbaceous stems, and every fragment of dead vegetable 

 matter, and in some degree of animal, are capable of developing 

 and supporting new vegetable forms which utilise and assimilate 

 the chemical products of decay, and inaugurate a new cycle of 

 activity. In this relation Fungi have been called the scavengers 

 of vegetation, since if they are powerful in the work of 

 destruction, they are also the ready agents in regeneration. 

 The method by which these results are accomplished is some- 

 what uniform. If a dead log or only a chip of wood lies upon 

 the ground in a damp situation, it soon becomes permeated by 

 the delicate, imperceptible threads of Fungus mycelium; with 

 the penetration of these threads the component cells of the 

 timber become more and more dissociated from each other, a 

 kind of fermentation softens the material, and it is not long 

 before the whole mass has become friable and crumbles at a 

 touch. Before this crisis is reached, and whilst the mass still 

 adheres together, the Fungus mycelium gives further evidence 



