56 RESEARCHES ON FUNGI 



By contrast, the chief points in connection with the mechanism 

 for the production and Hberation of spores in non-Coprinus Agari- 

 cineae, such as the species of Amanita, Psalliota, Panaeolus, etc., 

 all of which belong to the Aequi-hymeniiferous Type, are as 

 follows : 



(1) The gills are sometimes very thin but are usually relatively 



thick, 



(2) The gills are not parallel-sided but are more or less acutely 



wedge-shaped in cross-section, 



(3) The gills are positively geotropic, 



(4) Every part of the hymenium on any gill in a normally 



oriented fruit-body looks more or less downwards, 



(5) The spores do not ripen in succession from below upwards 



on each gill but more or less uniformly all over the gill- 

 surfaces, 



(6) The spores are not discharged in succession from below 



upwards on each gill but more or less uniformly all over 

 the gill-surfaces, 



(7) Autodigestion does not proceed from below upwards on each 



gill or involve any part of a gill during the period of spore- 

 discharge. 



In the light of these criteria, let us now consider the generic 

 position of Psathyrella disseminata. 



If one examines the gills carefully with the help of the microscope, 

 one finds that they satisfy the seven criteria for a non-Coprinus 

 lamellate fungus, possibly with the exception of the third. The 

 gills are (1) thin, but (2) they are acutely wedge-shaped in cross- 

 section. Whether or not they are (3) positively geotropic I do not 

 know. However, (4) every part of the hymenium on any gill in a 

 normally oriented fruit-body looks more or less downwards ; for 

 the stipe, by means of a very precise negatively geotropic reaction, 

 brings the median planes of the gills into approximately vertical 

 positions. The most important criteria are the fifth, sixth, and 

 seventh. The spores (5) do not ripen in succession from below 

 upwards on each gill but more or less uniformly all over the gill- 

 surfaces. The spores (6) are not discharged in succession from 

 below upwards on each gill but more or less uniformly all over the 



