28 RESEARCHES ON FUNGI 



in the main by growth in the size of the lower cells of the pileus- 

 fiesh surrounding the stipe at the disc. As soon as the spores are 

 ripe, this tiny mass of flesh turns upwards with respect to the centre 

 of the disc which thus becomes depressed and, in so doing, the flesh 

 carries the gills with it, thus raising the gills into a horizontal position 

 and flattening the whole pileus (Fig. 13, T>, E, p. 19). The opening 

 outwards of the pileus is doubtless aided by the swelling of the 

 paraphyses around the upper parts of the interlamellar spaces. 

 As this sweUing continues, the top of the pileus as a whole gradually 

 becomes concave (c/. Figs. 3 and 5, pp. 7 and 10). In Coprinus 

 curtus, as in C. sterquilinus and all other Coprini, the paraphyses are 

 the elastic elements of the hymenium and perform an important 

 mechanical function as the pileus opens. 



Owing to the presence of the radial grooves in the flesh, the 

 looseness and weakness of the tramal hyphae, and the swelling of 

 the giant tramal cells, each gill, when subjected to the tangential 

 forces derived from the disc-flesh and the paraphyses, which tend 

 to open out the pileus, splits radially from above downwards, thus 

 becoming Y-shaped in a vertical transverse section. The radial 

 sulcations thus produced in an expanded pileus can be readily seen 

 in the photographs reproduced in Figs. 2 and 8 (pp. 5 and 14), 

 and still more readily in the drawing of the upper side of a very 

 large expanded pileus, shown five times the natural size without 

 the scales and pilocystidia, reproduced in Fig. 18. In this figure 

 it will be seen that the pileus-flesh, except at the disc, is split into 

 radial ribbons and that each gill is partially cleft down its median 

 plane into two halves (c/. Fig. 19). The split part of each gill, seen 

 from above, turns from grey to dirty white as the spores are 

 discharged. 



The Discharge of the Spores and the Autodigestion of the 

 Gills.— The discharge of the spores of Cojirmus curtus begins imme- 

 diately after the pileus has been opened and flattened like a parasol ; 

 and, as in all other Coprini, it proceeds from below upwards in each 

 gill or, with respect to the pileus as a whole, centripetally (Fig. 13, C, 

 p. 19). Just before the first spores to be discharged are shot away 

 from their sterigmata, the basal part of the sterile flange of each 

 gill is destroyed by autodigestion, so that it does not impede the 



