n6 HESEARCHES ON FUNGI 



The number of spores produced per annum is probably much 

 less from a fruit-body of Fomes igniarius than from fruit-bodies 

 of F. applanatus and F. fomentarius, owing to the fact that the 

 annual tube-layers in this species are very shallow. A rough 

 count of the spores deposited on a slide during a 24-hour period, 

 August 2-3, gave a total of about 83,000 spores per square mm. 1 

 The medium-sized fruit-body which produced the spores from 

 which this count was made was about 32 square cm. in area. With 

 favourable conditions for spore-discharge, therefore, it probably 

 liberated about 260,000,000 spores in 24 hours. There are about 

 1,800 hymenial tubes per square centimetre of each tube-layer. 

 Each tube, therefore, may liberate about 4,600 spores per day. 2 



On some days the discharge of spores is much lighter than that 

 just indicated. Thus during 23 hours, August 7-8, only one spore 

 on the average was produced per 300 square microns of slide area, 

 or some 3,000 spores per square mm. This is only about one 

 twenty-eighth of the number of spores (83,000) produced per 

 square mm. during a similar period on August 2-3. 



Summarising, we may say that Dr. Bisby's investigation 

 indicates that for Fomes igniarius in Manitoba the usual course of 

 events connected with the annual spore-discharge period is as 

 follows : (1) the production of a new annual tube-layer during 

 the first part of the summer, leading to (2) the discharge of 

 spores for about two months (July, August, and the beginning 

 of September), followed by (3) a period of quiescence during the 

 late autumn, winter, and spring. Thus Fomes igniarius stands in 

 marked contrast with F. fomentarius which produces a new annual 

 tube-layer in the autumn and liberates spores from them in the 

 spring. 



Winter Break in the Spore-fall Period of Daedalea con- 

 fragosa. In Manitoba the winter often sets in early in November, 

 with the result that certain hymenomycetous fruit-bodies which 

 grow on logs, sticks, etc., have their spore-discharge period 



1 About 100 spores per 1,200 square p of slide in an average deposit, the deposit 

 being one or two layers deep and practically covering portions of the slide. 



2 Apparently not all portions of the pileus gave off spores simultaneously ; 

 but this irregularity requires further investigation. 



