422 RESEARCHES ON FUNGI 



present-generation and coming-generation basidia. It is not easy, 

 at the stage of development of the hyrnenium represented in Fig. 146, 

 to distinguish the paraphyses from some of the future-generations 

 basidia, but they undoubtedly are present in about the numbers 

 shown. As the hymenium grows older and more and more basidia 

 shed their spores and collapse, the paraphyses increase in diameter ; 

 and then they can be seen more easily. When the hymenium is 

 quite exhausted, the paraphyses alone have a turgid appearance, 

 and are then seen to be very numerous. A mushroom had been 

 shedding spores for six days and six nights. A few hours after the 

 cessation of spore-discharge, one of its gills was carefully examined 

 with the microscope and it was found that nearly all the basidia 

 had completely dissolved, so that their outlines could only be 

 traced here and there ; but the paraphyses could all be clearly 

 distinguished. A surface view of this totally exhausted hymenium 

 is shown in Fig. 152, C (vide infra, p. 448). 



It has frequently been denied that paraphyses, i.e. constantly 

 occurring permanently sterile elements, are present in the hymenium 

 of the Hymenomycetes 1 ; but the denials have been made by 

 cytologists who have been content to examine fixed and stained 

 microtome sections. By comparing the state of the living hymenium 

 of a single fruit-body day after day throughout the whole period of 

 spore-discharge for Pcmaeolus campanulatus and Stropharia semi- 

 globata, I proved the existence of paraphyses in those species. 2 

 A similar investigation upon the Mushroom has yielded a similar 

 result. I cannot entertain any further doubt that the hymenium 

 of Psalliota campestris contains numerous paraphyses destined 

 from their first origin to remain sterile. There does not seem to 

 me to be the slightest reason to suppose that these elements could 

 be caused to develop into basidia by any normal variation of any 

 of the natural conditions under which mushrooms grow. 



Since paraphyses are definite elements in the hymenium of 

 the Musliroom, one may ask : what is their function ? I am inclined 

 to think that they serve the purpose of assisting the basidia which 

 are to shed spores. They are the elastic elements of the hymenium. 



1 Cf. Chap. X, pp. 269-270. 



2 Vide Chap. X, pp. 279-281, and Chap. XI, pp. 336-337. 



