290 RESEARCHES ON FUNGI 



on arriving at the cystidia within a certain radius, causes the 

 protoplasm within the cystidia to produce or liberate enzymes which 

 attack the cell-walls. However, there is another possibility. The 

 spores are developed and discharged from below upwards on each 

 gill, and the order of their discharge appears to be dependent in part 

 at least upon the order of their development ; and it may be that 

 the order of autodigestion of the cystidia is merely dependent 

 upon the order in which the cystidia develop. But hitherto the 

 order of development of the cystidia has not been studied. 



The Interlamellar Spaces.— The existence of the interlamellar 

 spaces between the gills provides : (1) a space in which the basidia 

 of opposing gill-surfaces can develop without touching one another 

 and (2) sufficient room for the violent discharge of the spores in the 

 region of spore-discharge. As I have pointed out in the first volume 

 of these Researches, the spores of all Hymenomycetes, when moist, 

 are very adhesive and, when brought into contact with one another, 

 they stick together. If the spores on basidia of opposing gills were 

 to touch one another during their development, it is probable that, 

 during the subsequent expansion of the pileus, they would pull 

 one another off their sterigmata, with the result that later on they 

 would not be properly liberated. However, whilst the spores are 

 ripening, opposing gill-surfaces are entirely prevented from coming 

 into contact owing to the fact that they are kept apart by the 

 numerous cystidia which act as distance-pieces. 



The interlamellar spaces seem to be somewhat too wide, if we 

 are to imagine that their one function is to provide space for the 

 free development of the basidia and spores (c/. Fig. 122, p. 287). 

 However, as my earlier studies of the mode of spore-discharge in 

 the Agaricineae showed, the interlamellar spaces require to be suf- 

 ficiently broad to permit of the spores being violently discharged 

 into them without any risk of their striking and adhering to the 

 opposing gills toward which they are propelled.^ The spores of 

 Coprinus atramentarius are shot forward from the basidia for an 

 average distance of the order of 0-05 mm. It appears probable, 

 therefore, that, with the provision of space sufficient for the libera- 

 tion of the spores and with the further provision of a certain margin 

 1 These Researches, vol. i, 1909, pp. 40, 211-212. 



