436 



RESEARCHES ON FUNGI 



yellow. The fruit-bodies arise not from the top but from the base 

 of the host fruit-body, either singly or several together. Coloured 

 illustrations of the fimgus are to be found in Berkeley's Outlines of 

 Fungology ^ and in Boudier's splendid Icones Fungorum.^ 



Boletus parasiticus is the only member of the Polyporeae known 

 to be parasitic on another fungus. The fruit-bodies of the Sclero- 

 dermas which it parasitises are well fitted to afford it a nutrient 



Fig. 182. — Boletus parasiticus as a parasite on Scleroderma vulgare. 

 From M. J. Berkeley's Outlines of British Fungology. Natural 

 size. 



substratum, owing to their common occurrence in woods and heathy 

 places, their massiveness, solidity, and persistence. 



The parasitism of Boletus parasiticus on Scleroderma vulgare and 

 S. verrucosum finds a parallel instance among the Ascomycetes in the 

 parasitism of Cordyceps ophioglossoides and C. capitata upon Elapho- 

 myces granulatus, E. variegatus, and E. muricatus, with this difference : 

 that, while the fruit-bodies of the Sclerodermas are subaerial, those 

 of the Elaphomyces species are subterranean. Scleroderma vulgare ^ 



1 M. J. Berkeley, Outlines of Fungology, London, 1860, Plate XV, Fig. 4. 



2 E. Boudier, Icones Fungorum, Paris, 1904-1911, Tab. CLXV. 



^ W. B. McDougall, " On the Mycorrhizas of Forest Trees," American Journal 

 of Botany, vol. i, 1914, pp. 51-74. 



