PSALLIOTA CAMPESTRIS 401 



one A and the less advanced one B. Already by 11 A.M. the mush- 

 room A had produced a good spore-deposit on the slides, whilst 

 B had produced a distinct but relatively poor one. It was clear 

 that spore-discharge had already begun : possibly it had been in 

 progress in A for two hours, but in B probably for only about half 

 an hour. The glass slides were removed and replaced by new ones : 

 and during the whole period of spore-discharge this process of 

 periodical replacement was continued. Usually the slides were 

 changed twice a day, at about 10 A.M. and 8 P.M. respectively. The 

 continuance and vigour of spore-discharge were judged by the eye 

 from the density of the spore-deposits as seen against a background 

 of white paper. In order not to disturb the orientation of the 

 gills, the pots containing the mushrooms were not moved during 

 the whole period of observation. 



By making observations in the manner just described, it was 

 found that the mushroom A yielded strong spore-deposits for four 

 days and four nights. The spore-deposit made during the next 

 24 hours was only very thin, and at the end of this time the 

 fruit-body toppled over and collapsed. The mushroom B yielded 

 excellent spore-deposits for five days and five nights. During the 

 next day and night the spore-deposit was very thin and, toward 

 the end of this time, the mushroom fell over somewhat on its side. 

 Spores then ceased to be liberated, whereupon the mushroom soon 

 collapsed and became putrescent. 



From the above observations we may conclude that the spore- 

 discharge period of a wild mushroom is five or six days in length, 

 each day being reckoned as 24 hours. Doubtless, in nature, the 

 period is affected by weather conditions such as temperature and 

 moisture ; but, so far, I have not found it possible to investigate 

 their influence. 



At the moment when spore-discharge began, the pilei were 

 convex, but by the second day they had already become flattened. 

 The spores were therefore being shed whilst the gills were being 

 raised into their upward-inclined positions. This movement, as 

 we have seen, does not affect the verticality of the median planes 

 of the gills or prevent the hymenium from continuing to look more 

 or less downwards toward the earth. The discharge of the spores 



VOL. II. 2 D 



