GENERAL SUMMARY 



THE FOLLOWING IS A SUMMARY OF THE MORE IMPORTANT 

 RESULTS OBTAINED DURING THE INVESTIGATIONS 



PART I 



Chapter I.— In the Psathyrella Sub-type the fruit-body is ephemeral : 

 it opens, sheds its spores, and collapses within a period of about 24 hours. 

 The gills are not mottled. The basidia are tetramorphic, i.e. are of four 

 different lengths, and represent four distinct basidial generations with 

 overlapping periods of spore-development. The paraphyses are large 

 and form a hymenial pavement in which the basidia are set. The tetra- 

 morphism of the basidia permits of the basidia being laterally crowded, 

 the spores of the longer basidia overstanding those of the shorter ones ; 

 and the lateral crowding of the basidia leads to an increase in the number 

 of spores produced per unit area of hymenial surface. The small num- 

 ber of basidial generations and their overlapping periods of development 

 are correlated with the light structure and the ephemeral existence of 

 the fruit-body as a whole. 



The fruit-body of Lepiota cepaestipes, which belongs to the Psathy- 

 rella Sub-type of organisation, is described and illustrated. The spore- 

 discharge period was found to be of only about 15 hours duration. The 

 longest basidia discharge their spores first, the next longest next, and 

 so on for the two succeeding basidial generations until all the spores have 

 been liberated. 



Lepiota procera does not belong to the Psathyrella Sub-type. Its 

 fruit-bodies are not lightly built and ephemeral but stoutly built and 

 relatively persistent. The length of the spore-discharge period, under 

 natural conditions, was found to be 8 days. The basidia are not tetra- 

 morphic but monomorphic. The general organisation of the hymenium 

 appears to be very similar to that of Panaeolus campanulatus. 



Chapter II. — Psathyrella disseminata belongs to the Psathyrella 

 Sub-type. Although resembling Lepiota cepaestipes in its general mode 

 of producing and liberating its spores, P. disseminata is not closely 

 related to that fungus genetically. 



Psathyrella disseminata produces a red ozonium, not hitherto de- 



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