556 PHOSPHORESCENT FUNGI IN AUSTRALIA, 



It is a debated question whether the light proceeds from within 

 the organism or from excreted luminous metabolic products. 

 The researches of Radziscewski* seem to afford a reasonable and 

 simple explanation of the luminosity, and they support the latter 

 view. He found that certain organic substances such as the 

 aldehydes and aldehyde-ammonia derivatives, as well as fatty oils, 

 have the faculty of becoming luminous in alkaline solutions when 

 oxygen is present. Such compounds (e g., fatty oils) are known 

 in the phosphorescent fungi, and if they are united in an alkaline 

 solution with the oxygen obtained in respiration, the cause of 

 the luminosity might thus be explained. Oxidation products or 

 acids are formed from the luminous materials by the vital activity 

 of the organism and the luminous organs in P. candescens, viz., 

 the gills, were decidedly acid. The metabolic products are known 

 as phospkorescents, and, uniting with oxygen, they evolve light 

 outside the organism. 



Luminosity is a better term for the phenomenon than phos- 

 phorescence, since it is not of the same nature as true phosphor- 

 escence. The luminous fungi glow without previous exposure to 

 the sun, and the property cannot be excited by mere heat, as in 

 the case of certain mineral substances such as phosphorite. 

 Further, it is not due to the formation of some readily oxidizable 

 compound of phosphorus such as phosphu retted hydrogen in the 

 organism, as has been shown by Pfliiger. It is essentially a vital 

 phenomenon, disappearing immediately on death, and probably 

 the energy set free in the process of destructive metabolism is 

 evolved in the form of light. 



Use of phosphorescence to the plant. 



As regards the use of this luminosity to the plant, it may be 

 surmised that it serves to attract various insects to aid in the 

 dissemination of the spores. Just as many night-flowering plants 

 are white to reflect the smallest possible amount of light in order 



Bericht Ludwig's in Bot. Centralbl. Vol. vii., p. 325. 



