H4 RESEARCHES ON FUNGI 



its spores ; and the following statements are taken from the notes 

 that he kindly sent to me. 



The pilei observed were projecting from the trunks of Populus 

 tremuloides in the woods along the Red River at Winnipeg. Micro- 

 scope slides were placed on a platform just below each of two 

 pilei for the purpose of catching the spores immediately after 

 their discharge, and they were examined at frequent intervals to 

 determine the beginning of the spore-discharge period. 



The slides were first put out on April 15, 1921. The hymenial 

 tubes of the 1920 tube-layer were open ; but neither at that time 

 nor subsequently did they discharge any spores. 1 



On May 27, the centre of the fruit-bodies showed a dark brown 

 coating of the new hyphae which were to produce the new tube 

 layer. By June 21, signs of the production of pore openings in 

 the new growth were evident, but up to that time no spores had 

 been discharged. The slides could not be examined again until 

 July 17, at which time spores were being discharged in great 

 numbers. Thus the exact date at which the phenomenon of spore- 

 discharge began in 1921 was unfortunately not determined ; but 

 it must have been between June 21 and July 17. Probably it 

 was about July 1. 



The discharge of spores continued from the beginning of 

 the spore-discharge period (about July 1) until the beginning of 

 September. On the first day of September very few spores were 

 being liberated. The two fruit-bodies observed therefore had a 

 spore-discharge period in 1921 of about two months' duration. 



On some days during the spore-discharge period the discharge 

 of spores was much heavier than on others. It was less on cooler 

 days and, during a cool rainy period, very few spores were liberated. 



Tests during 24 hours, August 11-12, showed that about the 

 same number of spores was discharged during the 12-hour day 

 period (9 A.M. to 8.30 P.M.) as during the 12-hour night period 



1 Possibly in Fomes igniariiis, as in F. fomentarius, the tubes produced in any 

 one year are active for several years. The 1920 tubes may have produced spores 

 along with the 1921 tubes after the beginning of the spore-discharge period. This 

 matter requires further investigation. I observed continuity of the tubes in 

 successive tube-layers of some small fruit-bodies of the allied F. pomaceus gathered 

 from a Plum tree at Banbury, England. 



