BIOLUMINESCENCE OF DECAYING LEAVES 419 



grow as many forms as possible under the same conditions in the 

 laboratory and observe the results. 



The Bioluminescence of Decaying Leaves.— The biolumines- 

 cence of decaying leaves has been observed by Tulasne in France, 

 by MoHsch in Java and Germany, by myself in England, and by 

 Gilbert, Dosdall, and others in North America. As this pheno- 

 menon is geographically so wide-spread, intrinsically so interesting, 

 and yet so little known even to mycologists, I shall here review our 

 knowledge concerning it. 



Tulasne,^ in 1848, in France, discovered that decaying Oak 

 leaves sometimes emit light. At that time he was investigating 

 the emission of light from Bhizomorjjha suhterranea, which we now 

 know is not an independent species but merely a specialised part 

 of the mycelium of Armillaria mellea. He gathered some rhizo- 

 morphs in a wood and, to protect them from drying during transit 

 to his laboratory, wrapped them up with damp leaves and small 

 twigs of an Oak. On examining his material in the dark, he at 

 once perceived that light was being emitted not only by the rhizo- 

 morphs but also by the leaves. The leaves were those of the 

 previous year which had fallen in autumn, and they were damp, 

 elastic, and still somewhat firm. They did not give out light over 

 their whole surface but only in spots, more especially where the 

 brown leaf-colour had already become pale or whitish. 



For fifty years after the phenomenon of bioluminescence in 

 dead leaves had been discovered by Tulasne, it was neglected by 

 botanists. Then Molisch ^ resumed its study, and in ] 904 he 

 published the results of his investigations in his Leuchtende Pflanzen. 

 On his visit to the Botanical Garden at Buitenzorg he found that well- 

 rotted leaves of Bambusa, Nephelium, Aglaia, etc., gave out a white 



is also known that the composition of the medium affects the luminosity of certain 

 Bacteria. Thus a kiminous species which parasitises and kills the Sand-hopper 

 Talilrus (an amphipod Crustacean) is non-luminescent when grown on ordinary agar, 

 gelatine, or potato media, but resumes its luminescence when inoculated into a 

 healthy TaUtrus {vide Paul Buchner, Tier vnd Pflanze in intrazeUularer Symhiose, 

 Berlin, 1921, p. 342). 



1 L. R. Tulasne, " Sur la phosphorescence spontanee de VAgaricus olearius DC, 

 du Rhizomorpha suhterranea Pers. et de feuilles niortes du chene," Annal. d. scienc. 

 nat., s^r. 3, Tab. IX, 1848, p. 353. 



^ Hans Molisch, Leuchtende Pflanzen, Jena, 1904, pp. 47-51. 



