7 8 RESEARCHES ON FUNGI 



Hymenomycetes during development execute a set of complex 

 growth movements which are partly controlled by internal causes 

 and partly by external stimuli. These movements are correlated 

 with the general structure of the fruit-bodies, and with the 



FIG. 30. ArmiUaria mellea. Overcrowded group of fruit- 

 bodies growing on a living Mountain Ash (Pints 

 Aucuparia}. Photographed at Sutton Park, Warwick- 

 shire, by J. E. Titley. About J natural size. 



position of the surface of the substratum on which each species 

 grows. The result of the movements in all cases is to place the 

 hymenium in such a position that it can discharge its spores, so 

 that they may fall freely downwards into an open space from 

 which they may be carried off by the wind. 



