122 RESEARCHES ON FUNGI 



words, a zone of spore-development passes from the bottom to the 

 top of each gill, yet in these zones the basidia of the first generation 

 always take a slight lead in the times of the production and discharge 

 of their spores. In consequence of this, the broad zones of spore- 

 development and spore-discharge are each composed of two sub- 

 zones, a higher one belonging to the first-generation basidia and a 

 lower one belonging to the second-generation basidia. 



(6) Paraphyses are normal constituents of the hymenium. They 

 are elements which are destined to remain sterile until their de- 

 struction by autodigestion. They are very large and are united so 

 as to form a pavement through which the basidia protrude. They 

 not only support the basidia mechanically, but act as space-makers 

 so that adjacent basidia are separated from one another by a distance 

 just sufficient to prevent any jostling during spore-development 

 and spore-discharge. A similar system of paraphyses occurs in the 

 Psathyrella and Bolbitius Sub-types among the Aequi-hymeniiferae. 



(7) The pileus-flesh is very thin. Its amount is very small in 

 proportion to the large area of hymenial surface. This is particularly 

 noticeable when one compares large Coprini, e.g. Coprinus comatus 

 and C. atramentarius, with large Aequi-hymeniiferae, e.g. Lepiota 

 procera, Amanita rubescens, and species of Lactarius, Russula, etc. 

 In the smaller species of Coprinus, the very thin flesh usually splits 

 into radial ribbons as the pileus opens, and the lines of cleavage 

 are usually continued down the middle planes of the gills so that the 

 pilei open out like parasols. We find a similar condition in a few 

 Aequi-hymeniiferae, among which may be mentioned certain species 

 of Bolbitius and Psathyrella disseminata. This last species, however, 

 does not expand beyond the campanulate stage. The thin flesh of 

 the Coprini in general is correlated with the peculiar mode of the 

 production and liberation of the spores. This fact is best realised 

 from a study of the larger Coprini, e.g. Coprinus comatus and 

 C. atramentarius. 



(8) The stipe is hollow and its substance usually rather brittle. 

 In no species of Coprinus is the stipe solid. In the Aequi-hymenii- 

 ferae, on the other hand, some species have solid stipes and some 

 hollow. The hollow space in the stipe of a Coprinus is usually large 

 relatively to the thickness of the stipe-wall. The structure of the 



