286 RESEARCHES ON FUNGI 



(e) a zone which is spore-free, 



(/) a zone of autodigestion and, finally, at the gill-edge, 



(g) a liquid film containing the products of autodigestion and 

 the wasted spores. 

 It is clear from an inspection of the Figure that, oiving to their early 

 autodigestion, the cysiidia cannot possibly hinder the Jail oj the spores 

 and prevent their escape from between the gills. 



If one wishes to prove to one's self that the cystidia would form 

 a serious hindrance to the fall of the spores unless they were removed 

 in the manner described above, one has only to proceed as follows : 

 turnapileus which is shedding its spores, or a portion of it like that 

 represented in Fig. 122, upside down and then observe the cystidia 

 crossing the interlamellar spaces with the low power of the micro- 

 scope. One then sees that the spores continue to be shot out from 

 the basidia as under normal conditions but that, on falling down the 

 interlamellar spaces, they strike upon the cystidia, adhere to them, 

 and soon come to cover them with a dense dark spore-deposit. 



Since the cystidia of Coprinus atramentarins are essential con- 

 stituents of the fruit-body mechanism in that they alone prevent 

 the very thin, very broad, and very flexible gills from coming into 

 contact with one another, it is not surprising that we should find that 

 they are retained between the gills as long as is possible without 

 their becoming hindrances to the fall of the spores. They are 

 removed only just in time to prevent them from ever extending 

 between those parts of the gills where spore-discharge is taking 

 place. The cystidia-free portions of the gills which hang down- 

 wards (Fig. 122, zones c, d, e, /, and g), collectively, are only about 

 0-25 mm. in depth. They are kept apart by means of the cystidia 

 above them, so that there is no danger of the interlamellar spaces 

 between them becoming reduced in width. As a matter of fact, 

 the interlamellar spaces in the regions of spore-discharge are dis- 

 tinctly broadened out owing to a slight contraction of those parts 

 of the gills which are undergoing autodigestion (c/. zones d, e, f, 

 and g). 



The fate of the cystidia was found out by studying sections 

 about 1 mm. thick cut transversely through the gills. Some of the 

 sections were cut in planes which were transverse to the gill-edges 



