352 RESEARCHES ON FUNGI 



I have found fruit-bodies of Collybia radicata coming up on 

 two dead stumps. One of these stumps was at Kew Gardens and 

 the other at Birmingham. The former was in situ where it grew, 

 but the latter had been pulled up some two or three years previously 

 and had been laid upon the soil to support ivy. There can be no 

 doubt, therefore, that Collybia radicata can live as a pure saprophyte ; 

 and it may be that, even when it grows upon the roots of living 

 Beech trees, it is merely destroying roots which have been killed 

 by some other agency. However, it is not unlikely that the fungus 

 is a wound-parasite, i.e. a parasite which first invades the dead 

 tissues exposed at the surface of a wounded root and then slowly 

 invades and kills the living tissues adjacent to the dead tissues 

 first entered. The facts which lead one to suspect that Collybia 

 radicata is a parasite are : (1) the fungus grows on the roots of 

 living Beeches, Oaks, and Horse Chestnuts, (2) the fungus comes up 

 year after year beneath trees which have once become infected, 

 and (3) the fungus has developed a special organ — the pseudorhiza 

 — by means of which it successfully meets the requirements of its 

 subterranean mode of vegetation. Whether or not the fungus is 

 really a parasite, however, can only be decided by exact experiment, 



Collybia longipes ^ was found by Fayod above the roots of an 

 Oak. 2 Its pseudorhiza is doubtless developed in the same manner 

 as that of Collybia radicata ; and the fungus probably has relations 

 with the Oak of the same nature as those of C. radicata. 



Mycena galericulata. — This species Hves on dead wood. Its 

 fruit-bodies often develop at the surface of unburied stumps and 

 sticks, etc. Under these conditions each fruit-body consists of a 

 pileus and normal stipe only. However, it sometimes happens 

 that the woody medium in which the mycehum vegetates lies 

 several inches below the surface of the soil or vegetable mould. 

 When this is so, the stipe of each fruit-body possesses a pseudorhizal 

 prolongation similar to that of a stipe of Collybia radicata. The 

 accompanying illustration. Fig. 176, shows the relation of a group 

 of fruit-bodies to a block of wood which was buried about 4 inches 

 below the top of a layer of leaf -mould. The three fruit-bodies 



1 Vide Cooke's Illustrations of British Fungi, PI. 201. 



2 V. Fayod, loc. cit., p. 215. 



