COPRINUS MICACEUS 351 



Wettstein ^ states that the walls of the cystidia of Coprinus 

 micaceus are provided with very delicate, inner, ring-shaped, wall- 

 thickenings, which are difficult to see in fresh preparations but 

 which can be readily observed in stained ones which have first been 

 treated with a water-withdrawing reagent ; and he supports his 

 view with two illustrations of cystidia showing the supposed thick- 

 enings. I have looked very carefully for these thickenings in fully 

 turgid living cystidia, but have never been able to perceive them. 

 All the living cystidia seem to me to have an evenly thickened wall 

 like that shown in Fig. 157 at A, B, and C. However, as a full- 

 grown cystidium dies and collapses, wrinkles do appear upon it ; 

 but they are due, not to membrane- thickenings, but (1) to the local 

 ridging-up of the layer of protoplasm which is applied to the cell- 

 wall and (2) to wall-folding. In Fig. 157 at C is represented a 

 normal living cystidium with no sign of wrinkles upon it whatso- 

 ever. Now such a cystidium, if left for a short time immersed in 

 water, dies and becomes wrinkled. When dying, a cystidium con- 

 tracts somewhat in length owing to a loss of turgidity (Fig. 157, G, 

 H), and this leads to a ridging up of the lining layer of protoplasm 

 transversely (Fig. 157, H). Thus, to the observer, delicate lines 

 appear passing around the cystidium. Later on, the cystidium 

 becomes shorter still, and then the wall becomes distinctly folded 

 (Fig. 157, I, J). Exactly what Wettstein took for annular wall- 

 thickenings I do not know, but I am convinced from my own 

 observations that no such thickenings as he thought he saw occur 

 in the cystidia of Coprinus micaceus. 



The Discharge of the Spores.— In preparation for the begin- 

 ning of the process of spore-discharge, the pileus becomes campanu- 

 late. As the pileus expands, the radial furrows in the flesh open 

 out and the gills become well separated from one another, so that 

 between any two adjacent gills there comes into existence a fairly 

 wide interlamellar space (Fig. 158, C, D, E, p. 354). If one examines 

 a fruit-body at this stage of development from below with the naked 

 eye, one can see that the cystidia are too short to stretch across 

 the interlamellar spaces and appear as horizontal pegs projecting 



1 Richard V. Wettstein, " Zur Morphologie und Biologie der Cystiden," Sitzungs- 

 her. Kais. Akad. Wiss., med.-naturw. Kl, Wien, Bd. XCV, Abt. I, 1887, p. 15. 



