BIOLUMINESCENCE IN FUNGI 369 



The colour of the Hght emitted by luminous Hymenomycetes is 

 of more than one kind. In some species, e.g. Pleurotus japonicus, 

 it is white ; in others, e.g. Panus incandescens , green ; in others, 

 e.g. Panus stypt. luminescens, greenish-white ; in others, bluish- 

 green, etc. In no species at present known is it red.^ In the 

 common Armillaria mellea it is white but with a faint tinge of 

 bluish-green.2 



Spectrum analysis has shown that the light given out by lumin- 

 ous fungi and bacteria differs in its wave-lengths in different species, 

 but that in these organisms, as in animals, the spectrum is a con- 

 tinuous one.^ Ludwig,* in 1884, found that the spectrum of 

 Armillaria mellea stretches from about the middle of the yellow 

 region, through the green region, and well into the blue region (wave- 

 length 0-54— 0-46 fi) ; and Molisch,^ in 1904, found that the spec- 

 trum of Mycelium X (belonging to an unknown species) is rather 

 narrow, coincides practically with the yellow and green regions, 

 and is brightest in the green region (wave-length -57-0 -48 /x). 



The light emitted by luminous fungi doubtless resembles that of 

 the Fire-fly and the Glow-worm in not being accompanied by the 

 production of any appreciable amount of heat. Bioluminescent 

 organisms in their production of *' light without heat " are, from 

 the illuminating engineer's point of view, veritable marvels of 

 efficiency.® 



In 1915, Kawamura ' published an account of his studies of a 

 Japanese luminous fungus, Pleurotus japonicus, and his observations 

 were as follows. The fruit-bodies somewhat resemble those of 

 P. ostreatus and are found in imbricating clusters upon the decaying 



^ However, there is a Fire-fly, Photinus pyralis, which gives out a reddish glow. 

 Vide E. N. Harvey, loc. cii., p. 44. 



2 Cf. H. Molisch, loc. ciL, p. 122. 



^ Vide E. N. Harvey, loc. ciL, pp. 46-47, also Fig. 9. 



^ F. Ludwig, " tjber die spektroskopische Untersuchung photogener Pilze," 

 Zeitschr. f. wiss. Mikroskopie, Bd. I, 1884, pp. 181-190. 



^ H. Molisch, loc. cit., p. 132. Molisch, in his Fig. 13, shows comparative illus- 

 trations of the spectra of sunlight. Bacterium phosphoreum, Mycelium X, and the 

 beetle, Pyrophorus noctilucus. 



^ For a full discussion of this subject vide E. N. Harvey, loc. cit., pp. 40-66. 



' S. Kawaniura, "Studies on the Luminous Fungus, Pleurotus japonicus sp. 

 no v.," Journal of the College of Sci., Imper. Univers. of Tokyo, vol. xxxv, 1915, 

 Art. 3, pp. 1-29, Plates I-III. 



VOL. III. 2 B 



