216 RESEARCHES ON FUNGI 



Inocybe geophylla and Tubaria furfuracea, so that it is possible 

 that, if the fruit-bodies of these fungi had been more numerous, 

 some of them might have been found attacked. The species which 

 seemed to have been definitely avoided by slugs were Lactarius 

 quietus, L. rufus, Cottybia butyracea, Polyslictus versicolor and 

 Lycoperdon pyriforme. 1 



Two species of slugs were found upon the fungi, a larger reddish 

 one about one inch long (Fig. 75) and a smaller darker one. Mr. 

 P. T. Deakin kindly identified the former as Arion subfuscus var. 

 aurantiaca and the latter as a Limax. The specimens submitted 

 for the Limax were too immature for exact identification. 



Polystictus versicolor, Stereum hirsutum, and other tough and 

 leathery fungi, are probably protected against the ravages of slugs 

 by their physical consistence ; while Lactarius quietus, L. rufus, 

 L. glyciosmus, Cottybia butyracea, Laccaria laccata, and Lycoperdon 

 pyriforme are more or less protected against slugs by their 

 chemical contents. The majority of fleshy fungi, however, seem to 

 be in no way protected against slugs, and some of the commonest 

 species, e.g. those of Russula, Amanita, Amanitopsis, and Boletus, 

 often suffer most. On the whole, the most soft-fleshed species 

 seem to be the most relished by slugs, and these animals are par- 

 ticularly fond of the soft parenchymatous tissues of the Russulae 

 and of the soft hymenial tubes and flesh of many Boleti. Voglino 

 has supposed that slugs are important agents in bringing about 

 the dissemination and germination of the spores of Russulae, etc., 

 and is inclined to believe in the existence of symbiotic relations 

 between slugs and Hymenomycetes. 2 I am rather of the opinion 

 that, when a slug attacks a fruit-body, the advantage is chiefly, if 

 not entirely, on the side of the slug and that, from the point of view 

 of the fungus, the slug is a troublesome ectoparasite. As I pointed 

 out in Volume I, the fruit-bodies of the Hymenomycetes are beauti- 

 fully organised to secure the dissemination of the spores by the 

 wind and then: injury by slugs certainly prevents a great many 

 spores from being liberated. 3 



1 These five species are also distasteful to human beings. 



2 Vide these Researches, vol. i, 1909, pp. 226-227. 



3 Ibid., p. 228. 



