54 RESEARCHES ON FUNGI 



into view. Clear proof was thus obtained that the basidia were 

 shooting their spores more or less perpendicularly up wards. ^ 



A few seconds before the discharge of a spore a drop is 

 excreted at the spore-hilum, just as in all other Hymenomycetes. 

 Occasionally, after a spore and its drop have been discharged 

 together, a new drop is excreted at the end of the vacant sterigma. 

 This kind of abnormality I have observed also in Coprinus Rostru- 

 pianus and C. curtus (Fig. 20, E and F, p. 31). Excessive drop- 

 excretion from the spore-hila of the four spores of a single basidium, 

 followed by coalescence of the drops into one large drop and non- 

 discharge of the spores, takes place under very moist conditions, 

 as in Panaeolus campanulatus ^ and Coprinus sterquilinus.^ 



As we have seen, just before a pileus of Coprinus plicatilis 

 expands, there are a number of cystidia projecting across the inter- 

 lamellar spaces and from the margins of the shorter gills. In 

 C. atramentarius, C. lagopus, etc., each pleurocystidium suffers 

 autodigestion shortly before the upward-travelHng zone of spore- 

 discharge arrives at its level. In C. plicatilis, although during the 

 spore-discharge period the gills as wholes are not destroyed from 

 below upwards by autodigestion, we may yet ask whether or not 

 the cystidia are destroyed by autodigestion in succession from 

 below upwards as in the species just named. In an endeavour to 

 answer this question I gathered some large fruit-bodies which were 

 shedding spores and immediately examined the under sides of the 

 pilei with the low power of the microscope. Apparently the cystidia 

 along the gill-margins and on the gill-sides were disappearing in 

 fruit-bodies beginning to discharge their spores, and had already 

 disappeared in fruit-bodies in which spore-discharge was coming 

 to a close ; and two pleurocystidia were seen to excrete a drop of 

 fluid and then to retire to the gill-side. These observations suggest 

 that the pleurocystidia of C. plicatilis are actually autodigested in 

 the same manner as those of C. atramentarius * and C. lagopus ; 

 but, before this conclusion can be accepted without reservation, it 



1 These Researches, vol. i, 1909, p. 142. 



2 Ibid., vol. ii, 1922, p. 308, Fig. 104. 



3 Ibid., vol. iii, 1924, pp. 247-250, Fig. 106. 



4 For illustrations of autodigesting cystidia of C. atramentarius, vide these 

 Researches, vol. iii, 1924, p. 289, Fig. 123. 



