COPRINUS COMATUS 163 



showed that it travelled within the gill in the direction of the pileus- 

 flesh for a distance of 2-3 mm. Drops of water were absorbed by 

 an autodigesting gill-edge in the same manner as drops of red ink. 



The absorption of drops of water or red ink at the edge of an 

 intact or autodigesting edge of a gill is simply due to capillarity : 

 the water is sucked up into the spaces between the hyphae of the 

 trama {cf. Fig. 63, p. 160). 



During the autodigestion of a gill, as more and more cells are 

 destroyed, a considerable amount of fluid is constantly being set 

 free. The removal of this fluid from the gill-edge, where its undue 

 accumulation might interfere with the escape of the discharged 

 spores, is brought about in part by evaporation and, as indicated 

 by the experiments just described, in part by capillary suction into 

 the trama. Under dry atmospheric conditions much or most of 

 the fluid is rapidly removed by evaporation, but under very damp 

 atmospheric conditions a relatively small amount of the fluid evapo- 

 rates, the rest being sucked up into the trama. In the later stages 

 of pilear expansion the gills split radially from above downwards 

 for a certain distance in a Y-like manner, thus exposing to the sky 

 the two halves of the trama. The fluid absorbed by the trama 

 during autodigestion may thus become exposed on the top of the 

 pileus and evaporate there as well as at the free gill-edges. As 

 autodigestion proceeds and the gills become more and more reduced 

 to mere ridges, the fluid which has not been evaporated is set free 

 from the trama and collects in the form of drops at the periphery 

 of the pileus, i.e. where the gills have ceased to be active and, there- 

 fore, where hanging drops cannot interfere with the escape of the 

 spores. 



There is every reason to suppose that the capillarity of the trama 

 is of importance in removing from the gill-edge the fluid produced 

 by autodigestion, not merely in Coprinus comatus, but in many 

 other large Coprini, e.g. C. sterquilinus, C. picaceus, C. atramentarius, 

 and C. lagojnis. 



Coprinus comatus Parasitised by Stropharia epimyces.— It is a 

 remarkable fact that in North America the fruit-bodies of Coprinus 

 comatus and C. atramentarius are sometimes parasitised by another 

 agaric known as Stropharia epimyces (Peck) Atk. This parasite was 



