4 British Fungi. 



spore form the mycelium, in fact this name is ratlier 

 vague, but is generally understood to refer to the 

 hyphte concerned with vegetative work, and is either 

 buried in the substance from which the fungus obtains 

 its food supply, as in the common mushroom and most 

 mushroom-like fungi, or forms a more or less dense layer 

 on the surface, as in many moulds, sending branches 

 down into the substance it rests upon for the purpose 

 of absorbing food. In most cases the hypli^e penetrating 

 the matrix are of the ordinary filamentous kind, but 

 sometimes, more especially in the minute fungi 

 parasitic on living plants, the hyph^e that enter the 

 matrix become more or less expanded at the tip, form- 

 ing Jiaiistol'ia or suckers, which are supposed to 

 answer the double purpose of firmly fixing the fungus 

 and absorbing food. 



When young and actively growing, the hyphte 

 have very tliiu, colourless cell-walls, which usually 

 give a cellulose reaction, becoming violet when 

 treated with sulphuric acid and iodine, or a clear 

 blue with iodine alone, but when the hyphae are old 

 this reaction is rarely, if ever, obtained without special 

 and prolonged preparation, hence the name " fungus- 

 cellulose '' given by De Bary.- With age the walls 

 of the hyphfe frequently become coloured and 

 thickened to such an extent that the lumen or cavity 

 is almost filled up, and in some cases tbe thickened 

 wall shows distinct stratification, as pointed out by 

 De Bary -^ .in the inner layer of the exoperidium of 



- Fungi, Mycetozoa and Bacteria, English Edition, pp. 8 

 and 13. 



3 Tom. cit. p. 12. 



