COPRINUS CURTUS 29 



fall of the spores and so prevent them from escaping from the 

 pileus. In this respect C. curtus resembles C. comatus and 

 C. sterquilinus. 



The hymenium of a gill which is discharging its spores (Fig. 19) 

 exhibits, parallel to its gill-edge and from above downwards, five 

 zones : (1) a zone of basidia bearing ripe spores ; (2) a zone of 

 basidia discharging spores, consisting of a higher sub-zone where 

 only the long basidia are discharging spores and a lower sub-zone 

 where only the short basidia are discharging spores ; (3) a zone of 

 basidia which have discharged their spores ; (4) a zone in which 

 the basidia and paraphyses are undergoing autodigestion ; and 

 (5) a zone of the products of autodigestion, situated along the 

 gill-edge and containing the waste spores which failed to be 

 discharged. These five zones resemble in their structure and 

 physiology the similar series of zones on the gills of Coprinus 

 sterquilinus.^ 



During the discharge of the spores of Coprinus curtus the process 

 of autodigestion affects only the sterile flanges and the lower 

 unspht portions of the gills, the upper V-shaped portions of the 

 gills being left intact. These V-shaped portions of the gills, like 

 the two sides of the positively geotropic wedge-shaped gills of the 

 Aequi-hymeniiferae, always look downwards ; and, on this account, 

 from the point of view of the liberation of the spores, there would 

 be no advantage in their destruction from below upwards. ^ 



As the V-shaped parts of the gills liberate their spores, they 

 turn from grey to white, and this change in colour proceeds from 

 the periphery of the pileus toward the disc. After spore-discharge 

 has begun, one can observe with the naked eye that the pileus, as 

 a whole, consists of a white outer zone, which increases in width 

 by centripetal advance, and a grey central zone which steadily 

 diminishes in size and finally disappears. As the pilei of wild fruit- 

 bodies of Coprinus curtus are so small, the zone of spore-discharge 

 has only a few milhmetres to travel. Hence, in this species, when 

 contrasted with other Coprini having large gills, e.g. C. comatus and 

 C. atramentarius, the duration of the spore-discharge period is very 



1 Vide these Researches, vol. iii, 1924, pp. 239-257. 



2 Cf. these Researches, vol. iii, pp. 119, 128, 291, Fig. 124. 



