42 OUTLINES OF URITISH FUNGOLOGY. 



it must be remembered that vegetation goes on in the trunk 

 for nearly a twelvemonth before any Fungi can establish 

 themselves. The growth of Dry-rot is unfortunately familiar 

 to all^ and instances occur in which its spawn not only enters 

 the wood, but penetrates solid structures of brick. 



When spawn ha^ once taken possession of a spot favourable 

 to its growth, it is astonishing what an immense resistance it 

 will sometimes overcome. Large flagstones, for instance, are 

 sometimes raised by Mushrooms, and even tender species 

 like the Coprini (Plate 12, fig. 1) will sometimes resist a con- 

 siderable pressure. 



Where the spawn of Fungi has high powers of vegetation, but 

 no possibility of getting access to the external air, it assumes 

 peculiar forms which are sometimes extremely puzzling. In the 

 middle of a solid trunk, for instance, it forms black plates, — 

 as in the case of the common scaly Sapball, Pobjporus squa- 

 mosus, and several of the more solid Sphariacei, — while, when 

 running between the bark and wood, it assumes the form of a 

 flat, anastomosing, black seaweed, rather than of a Fungus, in 

 which cases it is known under the name of Rhizomorpha suh- 

 coriicalis, etc. This form is assumed by the spawn of various 

 Polypori and Xylarice, and in some cases the condition to a 

 certain extent seems to be almost normal. The absence of 

 light, too, impedes the proper development of Fungi, and 

 hence a variety of forms occur, very few of which perfect 

 their fruit. I have even found a Coprinus, which grew down 

 from the interior of the roof of a hovel, though perfect in 

 other respects, absolutely devoid of fruit. 



Spawn, as said above, may exist for years without pro- 

 ducing fruit, and it is probable that this is equally the case 

 whether it runs through soil or decaying substances, or 

 amongst living tissues, whether without or within their walls. 



