THE MICACEUS SUB-TYPE 329 



(3) The cystidia, in the unexpanded fruit-body, are not attached 

 by both ends to opposing gills. Some of them stretch across the 

 interlamellar spaces, but others do not and simply project from the 

 gOl-sides like so many pegs. The interlamellar spaces required to 

 provide room for the free development of the basidia and spores are 

 secured in part by the rigidity of the gills, in part by a suitable 

 spacing of the gills where they adjoin the flesh and at their margins 

 near the stipe, and in part by the cystidia which act as guards and 

 prevent two adjacent gills from anywhere touching one another 

 with their hymenial surfaces. 



(4) The cystidia do not bridge the interlamellar spaces during 

 spore-discharge. When spore-discharge is about to begin, the 

 pileus expands, adjacent gills become widely separated from one 

 another, and then all the cystidia project from the gUls in a peg- 

 like manner. 



(5) The pileus-flesh covering the gUls is membranous and pro- 

 vided with grooves which run radially above the longer gills. When 

 the pileus is expanding, just before and during the early part of the 

 spore-discharge period, these grooves open out. As expansion of 

 the pileus proceeds, the grooves deepen in such a way that the 

 longer gills become split down their median planes for a certain 

 distance. Finally, the ends of some of the long gills at the pileus- 

 periphery become completely split down their median planes into 

 two halves with the result that, in the later stages of its expansion, 

 the pUeus becomes torn into rays. 



(6) The basidia are tetramorphic. The longest set of basidia 

 is very protuberant, the next longest a little less protuberant, the 

 next longest still less protuberant, while the shortest set of basidia 

 is not protuberant at all. In the zone of spore-discharge there are 

 four sub-zones of spore-discharge corresponding to the four sets of 

 basidia. In having tetramorphic basidia and four sub-zones of 

 spore-discharge the Micaceus Sub-type is unique and shows the 

 highest degree of hymenial complexity in the Coprinus Type. 



Coprinus micaceus. — Coprinus micaceus (Fig. 148) is one of the 

 commonest of the larger species of Coprinus. Both in Europe 

 and North America its fruit-bodies, with their yellow ferruginous or 

 date-brown rimosely split pilei, may often be seen coming up in 



