COPRINUS PLICATILIS 55 



is desirable that the autodigestion of a number of individual pleuro- 

 cystidia should be followed in detail with the microscope. 



From a pileus which has begun to shed its spores one may obtain 

 a black spore-deposit on white paper within a few minutes. Under 

 field conditions, the spore-clouds are carried away from beneath the 

 pilei by the wind. As already pointed out, owing to the fact that 

 the spores of Coprinus plicatilis are relatively large and have a 

 high specific gravity, in still air they fall more rapidly than those 

 of most other Hymenomycetes.^ In a gentle breeze, before they 

 settle, they are therefore not likely to be carried to so great a distance 

 as the spores of Psalliota campestris, Marasmius oreades, and many 

 other grassland agarics. 



The Generic Position of Coprinus plicatilis. — In a special paper, ^ 

 pubhshed in 1919, and in Volume III of these Researches,^ in the 

 course of some critical remarks on the generic position of certain 

 Agaricineae, it was shown that, although Coprinus plicatilis has 

 lost one of its chief Coprinus characters, namely, autodigestion of 

 the gills, all its other characters are typically coprinoid ; and it was 

 concluded, contrary to the view of Massee, that the fungus must be 

 retained in the genus Coprinus. This conclusion has been supported 

 and strengthened by the detailed account of the structure and 

 mode of functioning of the fruit-body of C. plicatilis which has 

 just been given. 



The Absence of Autodigestion and its Significance. — In the 

 Coprini in general, in respect to the liberation of the spores, the 

 autodigestion of the gills is a mechanically advantageous process : 

 on each gill it proceeds from below upwards and destroys those 

 parts of the gills which have already shed their spores and which, 

 if they continued in existence, would hinder the fall of the remaining 

 spores. 



It is probable that the ancestors of Coprinus plicatilis had 

 gills which underwent autodigestion in the manner which is typical 

 for the genus Coprinus, but that this character was lost by C. 



' Vide supra, p. 48. 



'^ A. H. R. Buller, " Some Critical Remarks on the Generic Positions of Psathyra 

 urticaecola Berk, et Broome, Coprinus j^^icatilis Ft., and Psathyrella disseminata 

 Pers.," Tratis. Brit. Myc. Soc, for 1916, vol. v, 1917, pp. 482-489. 



3 These Researches, vol. iii, 1924, pp. 137-140. 



