BY D. McALPINE. 553 



They certainly occur on the trunks of living trees, although the 

 bark of the particular portion to which they are attached is dead, 

 but that is probably due to the destructive action of the mycelium 

 of the fungus. 



Observations on Pleurotus candescens, F.v.M. & Berk. 



Specimens of this fungus are very common during April and 

 Ma}- in the neighbourhood of Melbourne, and a few observations 

 were made on the phenomenon of phosphorescence this year. 



Specimens were detached from a Tea-tree trunk on the after- 

 noon of 6th April and retained their phosphorescence for at least 

 a week. 



The luminosity was confined to the gills, with the exception of 

 the downy material (mycelium) at the base of the stem, from 

 which, however, it disappeared in about two days. Portions of 

 the cuticle were removed from the pileus, also the white flesh, but 

 there was not the slightest trace of phosphorescence. The white 

 spores were shed in great abundance, but they showed no signs 

 of luminosity. 



The phenomenon was exhibited during the day as well as at 

 night, for when specimens were taken into a dark cellar they 

 shone equally well. 



The effect of moisture was also tested by immersing a piece of 

 the gills in water. After immersion for an hour and a half, no 

 perceptible effect on the luminosity was observed except, perhaps, 

 it was just a shade duller. 



The light emitted was a whitish glimmer with a faint sugges- 

 tion of blue, but the phosphorescent light is not the same in all 

 species of fungi. In some species it is more bluish, in others 

 more greenish or greenish-yellow, and in a third more of the 

 white light. The gills gave a decided acid reaction when fresh 

 and in the full glow of luminosity. 



In order to test the effect of the luminous glow on the photo- 

 graphic plate, Mr. A. J. Campbell, F.L.S., kindly tried a speci- 

 men. He exposed an ordinary photographic plate for an hour above 

 36 



