FIXATION OF FRUIT-BODIES 93 



year-old fruit-body is due in part to the mycelial hyphae, which at 

 first break through a relatively small hole in the bark and give rise 

 to the fruit-body, but chiefly to the fruit-body itself ; for this, as 

 it develops, flattens itself out over the uninjured bark and attaches 

 itself very firmly to the bark by means of its adhesive hyphae. 



Fig. 53. — Forties fomenturius. The back of a fruit-body, two 

 years old, which grew on a Birch tree near the Lake of the 

 Woods, central Canada. To show the mode of attachment 

 of the fruit-body to the tree. The mycelium burst through 

 the bark only in the area a. The fruit-body began its 

 development at a and then grew downwards, tending to 

 take a conical form but being prevented from doing so by 

 the presence of the tree-trunk against which it came to 

 press. It became so firmly adherent to the tree-trunk that 

 when it was forcibly broken away therefrom, as shown at 

 b, it carried with it a thin outer sheet of the birch-bark 

 (cork) which is easily recognisable by the characteristic 

 lenticels. Natural size. 



Other Fomes species, e.g. F. officinalis and F. applanatus, attach 

 themselves to tree-trunks in a similar manner. 



In many terrestrial Agaricineae, e.g. Amanita rubescens, Lepiota 

 procera, Psalliota campestris, Paxillus involutus, and Coprinus 

 picaceus, a fruit-body, at first, is a minute rudiment produced upon 

 a dense mycelium which permeates leaf-mould or earth rich in 

 organic remains. This rudiment is formed at or near the surface 

 of the ground. As it develops, the stipe becomes more or less 



