COPRINUS ATRAMENTARIUS 277 



riyius atramentarius consists of three kinds of elements : basidia, 

 paraphyses, and cystidia. The basidia have the usual coprinoid 

 structure and arrangement, i.e. they are dimorphic and crowded, 

 so that the spores of the long basidia often stand in part 

 over the spores of the short basidia (Fig. 120, zone a — a, p. 281). 

 From three to five paraphyses surround each basidium and thus 

 separate adjacent basidia from one another. The degree of 

 crowding of the basidia varies somewhat according to the extent 

 to which the gills have become stretched during the opening of the 

 pileus. While the gills are stretching, the paraphyses, which alone 

 are the elastic elements of the hymenium, expand ; and thus the 

 basidia become more and more separated from one another. The 

 distribution of the spores is shown in Fig. 117 (p. 276). The absence 

 of spores around the cystidia is due to the fact that every cystidium 

 is encircled by paraphyses. The distribution of the cystidia has 

 been sufficiently discussed already. The general significance of the 

 arrangement and structure of the basidia and paraphyses is exactly 

 the same as in Coprinus comatus and C. sterquilinus.^ 



The spores of Coprinus atramentarius ripen from below upwards 

 on each gill ; and, as they ripen, they turn dark brown. In the 

 mass, therefore, they appear to be almost black. Hence it is that 

 the gills are black at their bases first and that the blackening 

 process progresses from below upwards on each gill. Stages in the 

 blackening of the gills are shown in Figs. HI (p. 265), 113 (p. 269), 

 and 118, A, B. 



The Process of Spore-discharge. — When the pileus has become 

 expanded to the extent shown by the broken gill-lines at B in Fig. 118, 

 the process of spore-discharge begins. The first spores to be dis- 

 charged are those which are situated in the narrow zone which 

 extends along both sides of the extreme lower margin of each gill 

 (Figs. 118, B, s, and 117, p. 276). As in Coprinus sterquilinus , the 

 long basidia in this zone discharge their spores slightly in advance 

 of the short. The zone of spore-discharge moves slowly up both 

 sides of each gill from the bottom to the top. 



As soon as a narrow zone (somewhat less than 0-25 mm. wide) 

 along the bottom of each gill has become spore-free owing to spore- 



1 CJ. pp. 156-157, 206. 



