BASIDIA AND THE DISCHARGE OF SPORES 3 



jeunes." De Bary, 1 Fayod, 2 and others, however, have regarded 

 paraphyses as distinct from basidia. My own observations made 

 during the last thirteen years have convinced me that this view is 

 the correct one. I shall presently describe new methods for dis- 

 tinguishing the hymenial elements from one another, and shall 

 show that with their help it has been possible to determine that 

 paraphyses, i.e. cells which in general resemble immature basidia 

 but which are destined from the first to remain sterile, are present 

 in the hymenium of various species of Coprinus, Psathyrello, dis- 

 seminata, Panaeolus campanulatus, Anellaria separata, Stropharia 

 semiglobata, Psalliota campestris, Galera tenera, Bolbitius flavidus, 

 and Lepiota cepaestipes. 



During the gradual exhaustion of the hymenium by the pro- 

 duction and liberation of spores, the paraphyses lose all their 

 protoplasm except a very thin wall-layer and, at the same time, 

 become greatly swollen. The manner in which they assist the 

 basidia to perform their functions will be discussed subsequently 

 in connection with the description of various hymenia. 



Cystidia, like paraphyses, are sterile elements, but they differ 

 from these in their larger size, their peculiar form, their smaller 

 number, and frequently in the nature of their cell-walls and of their 

 contents. They are present in some species and not in others. In 

 some species where they occur, but not in all, they produce character- 

 istic excretions, while in certain Coprini they have a mechanical 

 function. They will be treated of more fully in Volume III. 



It is now known that the two nuclei present in each basidium 

 from the beginning of its differentiation fuse together and thus 

 consummate a sexual act of which the first stages take place in the 

 mycelium. 3 According to Ruhland, 4 the well-marked paraphyses 

 of Coprinus porcellanus at first, like the basidia, contain two nuclei ; 

 but these two nuclei never fuse and, finally, as the paraphyses 

 swell up and become poorer and poorer in protoplasm, undergo 

 degeneration. Ruhland also found pairs of nuclei in the large 



1 A. de Bary, Vergleichende Morph. u. Biol. der Pilze, Leipzig, 1884, p. 326. 



2 V. Fayod, " Prodrome d'une Histoire Naturelle des Agaricines," Ann. Sci. 

 Nat., T. IX, 1889, p. 253. 



3 Vide infra, vol. iv. 4 W. Ruhland, loc. tit. 



