GENERAL SUMMARY 463 



part of the hymenium produces and liberates spores during the whole 

 period of spore-discharge ; and (6) the gills are not destroyed from 

 below upwards by autodigestion. The name Aequi-hymeniiferae refers 

 to the equal development of the different parts of the hymenium . 



In the Inaequi-hymcniiferae : (1) the gills are very thin ; (2) the 

 gills are not wedge-shaped but, on the whole, parallel-sided or sub- 

 parallel-sided ; (3) the gills are not positively geotropic ; (4) usually 

 the hymenium on one side of a gill at maturity looks slightly downwards 

 and that on the other side slightly upwards ; (5) the spores ripen in 

 succession from below upwards on each gill ; (6) the spores are dis- 

 charged in succession from below upwards on each gill ; and (7) auto- 

 digestion proceeds from below upwards on each gill and removes those 

 parts of the gills which have become spore-free and which, if they 

 continued in existence, would become mechanical hindrances to the fall 

 of the remaining spores. The name Inaequi-Jiymeniiferae refers to the 

 unequal development of the different parts of the hymenium, the pro- 

 duction and liberation of the spores proceeding in a zone-wise manner 

 from below upwards on each gill. 



Chapter X. In the Panaeolus Sub-type the gills are mottled. 

 Mottling is an expression of the fact that the hymenium is made up of 

 a mosaic-work of small irregular local areas, the basidia in the darker 

 areas bearing older pigmented spores and those in the lighter areas 

 either no spores at all or spores which are younger and as yet unpig- 

 inented. With the discharge of the spores, a dark area turns light ; 

 and, with the ripening of the spores, a light area turns dark. 



Mottling of the gills occurs not only in Panaeolus but also in Anellaria, 

 Psilocybe, Hypholoma, Stropharia, PsaUiota, Cortiiiarius, Crepidotus, 

 Flaminula, and Pholiota. 



The changes taking place in one and the same piece of hymenium 

 of a living gill of Panaeolus campanulatus were observed during three 

 days and three nights with a horizontal microscope. It was discovered 

 that each area of the hymenium gives rise to a series of successive 

 generations of spore-bearing basidia, each area changing from black to 

 white alternately many times in succession. 



The fall of spores from a fruit-body of Panaeolus campanulatus 

 continues for about 8-11 days ; and it is the development of successive 

 generations of basidia on the local hymenial areas which enables spores 

 to be discharged as an uninterrupted spore-stream during the whole 

 of the spore-discharge period. 



In any small area of the active hymenium of Panaeolus campanulatus 

 (0-2 square mm.), the hymenial elements can all be placed in one or 

 other of the following five classes : (1) past-generations basidia, (2) 

 present-generation basidia, (3) coming-generation basidia, (4) future- 

 generations basidia, and (5) paraphyses. This analysis greatly simplifies 

 our conception of the organisation of the hymenium of Panaeolus 



