430 RESEARCHES ON FUNGI 



through the woods in the dark having rendered my eyes very 

 sensitive to weak hght, I re-examined the fruit-bodies ; and, to my 

 surprise, I found that the interior part of each stipe-half was 

 luminous for a distance of 0-25-0 -5 inch upwards from the very 

 base of the stipe. The unspUt stipes were non-luminous. 



During the night following the observation just described 

 there was a sharp frost, and next day I could find only one more 

 group of Armillaria fruit-bodies that was still in good condition. 

 I gathered some of these fruit-bodies, cut them down the centre, 

 took them to Winnipeg, and put them in a moist crystalUsing dish. 

 At night, just as before, I perceived that the internal basal parts of 

 the stipes were luminous. The luminosity was faint and extended 

 upwards from the base of each stipe for a distance about equal to 

 the breadth of my thumb. 



Kawamura ^ observed that the luminescence of Pleurotus japo- 

 nicus is confined to the gills. On the other hand, Tulasne^ states 

 that in Pleurotus olearius the luminescence " is not exclusively 

 confined to the hymenial surface," and he adds : "Numerous obser- 

 vations prove that the whole of the substance participates very 

 frequently, if not always, in the faculty of shining in the dark." 

 Tulasne split a stipe of P. olearius, bruised it, and divided it into 

 small fragments, but yet found that " the whole of the mass even 

 in its deepest parts enjoyed in a degree similar to its superficies the 

 property of light." It is evident that the fruit-bodies of the central- 

 Canadian strain of Armillaria mellea, upon which my observations 

 were made, differ from the fruit-bodies of Pleurotus japonicus and 

 P. olearius in that their luminescence was confined to the inner 

 tissues of the base of the stipe. 



In the summer and autumn of 1922, whilst resident in England, 

 I examined in the dark the interior of the stipes of a number of 

 Armillaria mellea fruit-bodies gathered at King's Heath and Barnt 

 Green in Worcestershire and at Keswick in Cumberland, but in no 

 instance could I detect the faintest trace of light. In 1923, similar 



^ S. Kawamura, "Studies on the Luminous Fungus, Pleurotus japonicus,''^ 

 Journ. of the College of Sci., Iniper. Univers. of Tokyo, vol. xxxv, 1915, pp. 6-9. 



" L. R. Tulasne, loc. cil. (vide p. 419) ; also Cooke and Berkeley, Fungi, etc., 

 London, 1882, p. 106. These authors have translated several pages of Tulasne's 

 description of Pleurotus olearius. 



