444 RESEARCHES ON FUNGI 



Camera-lucida Studies of a Nearly Exhausted Hymenium. The 

 studies of the hymenium represented in Fig. 151 were made upon 

 an old and nearly exhausted mushroom obtained from a field in. 

 England. The top of the mushroom was flat, and the gills were 

 of a dark reddish-brown colour, indeed almost black ; but the 

 mottling of the hymenial surface could still be discerned. Evidently 

 the fruit-body had been shedding spores for some days and was 

 nearing the point of exhaustion. Sections of the living gills were 

 made with a hand-razor as before, and two of them are shown at 

 A and B in Fig. 151. 



In Fig. 151, A, the elements nos. 1, 2, and 3 are present-genera- 

 tion basidia from all of which the spores were knocked off in cutting 

 the section as at no. 3 ; but in nos. 1 and 2 the spores have been 

 restored semi-diagrammatically. No. 4 is an old past-generation 

 basidium arising deep down in the subhymenium from the cell 

 no. VIII. The outlines of the other past-generations basidia 

 cannot be clearly discerned, but it is evident that their gelatinised 

 tops make up the general level of the hymenium which can be seen 

 at I. There are no coming-generation basidia included in the 

 section. Elements nos. 5, 6, and 7 are paraphyses. Two waste 

 spores, w, are lying on the hymenium. The subhymenium consists 

 roughly of three layers of cells : I to IV inclusive, V to VII 

 inclusive, and VIII to X inclusive. It is evident that the past- 

 generations basidia have all disappeared from the section except 

 no. 4 ; otherwise it would be possible to observe their outlines 

 and their attachments to the cells of the two upper layers of the 

 subhymenium. 



In Fig. 151, B, the elements nos. 1 and 2 are present-generation 

 basidia from which the spores were knocked off in cutting the 

 section ; but for no. 2 the spores have been restored semi- 

 diagrammatically. Nos. 3 and 4 are coming-generation basidia, 

 the presence of which indicates that the mushroom, although old, 

 would continue to discharge spores for at least half a day and 

 possibly for twenty-four hours longer. The past-generations 

 basidia which can be clearly distinguished are elements nos. 5, 

 6, 7, 8, and 9. The tops of other past-generations basidia, the 

 walls of which have apparently been gelatinised, make up the 



