COPRINUS STERQUILINUS 233 



The zone of autodigestion, which has come into existence in the 

 manner explained above, gradually ascends each gill ; and thus all 

 the gills are destroyed from below upwards. The zone of auto- 

 digestion follows hard after the zone of spore-discharge, but never 

 invades it. It simply involves the lower part of the zone which 

 has become spore-free. 



After autodigestion has begun, five zones can be distinguished 

 in succession from above downwards on the surface of each gill 

 within half a millimetre of, and parallel to, its edge (Figs. 104 and 

 105, pp. 242 and 249) : (a) a zone of basidia with ripe spores which 

 extends upwards toward the top of each gill and which therefore 

 may be several mm. high, (6) a zone of spore-discharge composed 

 of two sub-zones, (c) a zone of spore-free surface, (d) a zone of 

 autodigestion, and (e), at the gill-edge, a dark adhesive liquid film 

 containing the products of autodigestion and a certain number of 

 spores which have failed to be properly discharged. These five 

 zones keep their relative distances apart unaltered. They gradually 

 move upwards, so that in large fruit-bodies, in the course of from 

 eight to twelve hours, they involve the whole of each gill. 



Fig. 97 — cont. 



below to a horse-dung ball, has attained almost its full height. The annulus 

 has now been dropped by the pileus on to the stipe. In consequence of the 

 ripening of the spores, the gills are turning black from below upwards. D, a 

 section through an older pileus. In consequence of the spores having ripened, 

 the gills have become black all over. Spore-discharge would begin in about half 

 an hour. E, a section through a pileus about I "5 hours after spore-discharge 

 has begun. Spores are being shed and autodigestion is taking place along 

 the gill-edge at a. The broken lines show the shape and extent of the gills at the 

 moment when autodigestion began, s, the lower edge of the gill where spore- 

 discharge and autodigestion first became active. About one-fifth of each gill 

 has now been destroyed. F, a section through a still older fruit-body about 

 3' 5 hours after the beginning of spore-discharge. The pileus has now become 

 helmet-shaped through expansion. The gills have become reduced by auto- 

 digestion to about one-half their original size. A cloud of spores is being liberated 

 at the gill-edges. The line o — p shows the direction in which a section was 

 taken which is represented in Fig. 101, A (p. 237). G, a section through a 

 still older fruit-body, about 5 hours after the beginning of spore-discharge. 

 The pileus has become almost flattened at the top. The gills have now become 

 reduced by autodigestion to about one-quarter of their original size. The 

 exhausted parts of the gills have become recurved. On the right-hand side 

 is seen a drop of brown fluid which has come into existence through auto- 

 digestion. Tlie spores are shown diagrammatically escaping from the lower 

 edges of the gills. H, section of a pileus in the last stage of its development, 

 about 7' 5 hours after tlie beginning of sjiore-discharge and about 8 hours after 

 the stage shown at D. Tlie gills have now become reduced by autodigestion 

 to mere ridges. Spore-discharge is ceasing. The exhausted parts of the 

 gills are turned upwards. The few spores still in course of being shed are shown 

 diagrammatically, escaping from the lower edge of the gills. All natural size. 



