112 RESEARCHES OX FUNGI 



color lends considemble support to these general field observations. 

 A stick, about 4 cm. thick and ."SO cm. long, bearing a number of 

 fruit-bodies of the fungus in question, was gathered by myself and 

 kept in a dry state as a museum specimen. After an interval of 

 four years it was found that the fruit-bodies, on being moistened 

 in the usual manner, did not shed any spores, but appeared to be 

 discoloured and to have lost their vitality. The stick was then 

 given to Miss J. S. Bayliss for certain investigations which she 

 was then carrying on. It was set in a damp-chamber with one end 

 in water. Four weeks later Miss Bayliss observed that a number of 

 new fruit-bodies of Poly st ictus versicolor had begun to develop 

 upon it. In the course of a few weeks some of them attained 

 considerable size.^ This observation seems to me to prove con- 

 clusively that the mycelium in the wood must have retained its 

 vitality for four years in the desiccated condition. 



It is well knoAvn that the mycelium of PsaUiota camjiestris, 

 when kept dry as "spawn" in compressed horse-dung bricks, re- 

 tains its vitality for years. According to Falck,- the mycelium of 

 Coprinus sterqitilinus is still able to continue its development after 

 the horse-dung balls, in Avhich it has existed, have been kept dry 

 for a year. In both these instances the vegetative part of the 

 fungus is resistant to desiccation, whereas the reproductive part 

 is not. 



The xerophytic, hymenomycetous fruit-bodies growing on logs, 

 such as those named in the Table, have several features in 

 common. This is only what might be expected when it is 

 remembered that they are all adapted to the same external 

 conditions, i.e. to develop on a wooden substratum chiefly in 

 the cool and late autumn months. The points of agreement are 

 as follows : — 



1. They retain their vitality for months or years after desiccation. 



2. They are all firmly built and resemble in consistency leather, 

 cork, or wood. Tluir toughness renders them inedible to slugs 

 and favours their persistence through periods of drought and frost. 



^ Miss J. S. Bayliss, "The Bioloi^y of Polif-iticliis versicolor (Fries.)" Journ. of 

 Economic liioloijij, vul. iii., 1U08, p. 2U. 



- R. Falck, Ikitrdije ::ur liioloyie der PJlanzcii, Bd. \'l 1 1., 1902, p. ;517. 



