FOMES APPLANATUS 131 



fruit-body must have been approximately 930 X 2,080 or about 

 2,000,000. Since from these 2,000,000 tubes 30,000,000,000 spores 

 were liberated in 24 hours, the average rate of emission of spores 

 from each tube must have been about 15,000 per day of 24 hours, 

 or about ten per minute, or about one every six seconds. 



The Spore-discharge Period. White has discovered that 

 Fomes applanatus has a spore-discharge period which continues 

 day and night uninterruptedly not for a few days only or even for a 



FIG. 48. Fomes applanatus, a species with an annual spore-fall period of about 

 six months' duration. Vertical section through a fruit-body three years old. 

 The lowest and last-formed hymenial tube-layer is shedding clouds of spores. 

 Specimen obtained at Munich, Germany. Reduced to \ natural size. 



few weeks but for six whole months ! No other fungus, so far as is 

 yet known, sheds spores for anything like so long a time. White 

 made continuous observations on spore-discharge from one and 

 the same fruit-body for the full twelve months of each of the years 

 1915 and 1916. Spore-traps were set under the fruit-body from 

 early spring until late autumn daily, and during the winter weekly. 

 In addition to this unbroken series of observations during two years 

 on one fruit-body, other observations upon spore-discharge were 

 made upon other fruit-bodies during shorter periods each summer. 1 

 White's observations show that, in the neighbourhood of 

 Toronto, Canada, the spore-fall period of Fomes applanatus begins 



1 J. H. White, loc. tit., p. 140. 



