MUSSON : LUMINOUS WOOD. 



' The phosphorescence or kiminosity observed in several fungi 

 depends on the respiration of oxygen. Those fungi which exhibit 

 luminosity ceasing to do so when the oxygen is extracted.' 



My friend, Mr. R. A. Rolfe, of Kew Gardens, writes me with 

 reference to a piece I sent up for inspection : — 



^ Three summers ago, when at Colwick (Notts.), I came across a 

 large luminous stump. On returning here I went to my colleague 

 (Dr. M, C. Cooke) for advice. He told me the phenomenon had been 

 frequently observed ; that it was due to the mycelium of a fungus, 

 probably a Polyporus, possibly to more than one species, but which 

 no one appears to know.' 



In the Gardeners' Chronicle, February 2rst, 1882, vol. 13 (new 

 series), p. 240, I find a note from the Rev. M. J. Berkeley, to the 

 following effect : — He describes a new species, Agaricits {PleuroUts) 

 emerici, from the Andaman Islands, and says, ' The only instances of 

 luminosity which have occurred at home have been confined to 

 myceha, in conjunction with decaying wood or fermenting leaves.' 

 He then says, ' In the case of the new agaric it is no question of 

 decomposition, for the specimens are quite young and not fully 

 grown. The pileus is about half an inch across, attached behind 

 without any stem, either nearly flat or helmet shaped, the entire 

 substance being luminous. The cause is at present, we believe, 

 unknown ; even the opportunity of examining the large olive tree 

 agaric of the south of Europe has been without result. Next, I may 

 say that my colleague, Mr. N. E. Brown, examined the wood micros- 

 copically, under a low power ; the whole (a thin slice) appeared 

 luminous or nearly so, and under a high one it was barely visible. 

 The brilliancy to the naked eye would seem to be owing to con- 

 centration, as the magnifying process renders it almost invisible ; he 

 could not make out whether the fight was from the wood, or from 

 mycelium in the wood.' 



Is the luminosity owing to the mycelium of a fungus? Or is it in the 

 wood, and caused by the action of the mycelium of a fungus hastening 

 decom])osition % Or is the mycelium itself luminous; and if so, does 

 it belong to one or more species, and what species does it belong to? 



I think we may conclude that it is in some measure due to the 

 presence of the mycelium of a fungus (possibly of several species). 

 Further than that our knowledge at present will not take us. 



References to articles on this subject :^ — Cooke's Fungi, p. 105 ; 

 Berkeley's Introduction to Cryptogamic Botany, p. 265 ; Gardeners' 

 Chronicle, 1 87 2, p. 1258; Phosporescence (a work recently published); 

 Science Gossip, 187 1, p. 121. 



Sept. 1885. 



