LUMINOSITY. 393 



do not for a moment suppose that the mycelium is 

 essentially luminous, but are rather inclined to be- 

 lieve that a peculiar occurrence of climatic condi- 

 tions is necessary for the production of the pheno- 

 menon, which is certainly one of great rarity. 

 Observers as we have been of fungi in their native 

 haunts for fifty years, it has never fallen to our lot to 

 witness a similar case before, though Professor 

 Churchill Babington once sent us specimens of 

 luminous wood, which had, however, lost their 

 luminosity before they arrived. It should be observed 

 that the parts of the wood which were most 

 luminous were not only deeply penetrated by the 

 more delicate parts of the mycelium, but were 

 those which were most decomposed. It is pro- 

 bable, therefore, that this fact is an element 

 in the case as well as the presence of fungoid 

 matter." 1 



Another incomplete fungus growth is that called 

 Rhizomorpha subterranea, which extends underneath 

 the soil in long strings in the neighbourhood of old 

 tree stumps, those of oak especially, which are be- 

 coming rotten, and upon these it is fixed by its 

 branches. These are cylindrical, very flexible, branch- 

 ing and clothed with a hard bark, encrusting and 

 fragile, at first smooth and brown, becoming later 



1 "Gardener's Chronicle," 1872, p. 1,258. 



