26 RESEARCHES ON FUNGI 



times past the vertical. An account of this phenomenon which 

 was called geotropic swinging was given in Volume I.^ 



The Ripening of the Spores. — The spores on the tiny gills of 

 Coprinus curtus, just like those on the large gills of C. comatus and 

 C. atrame^itarius, ripen on each gill in succession from below upwards. 

 They are at first colourless ; they then turn brown and finally 

 black. At one stage in the development of the pileus there is a 

 distinct gradation in the shade of each gill from black to brown 

 from below upwards. This gradation in colour is less easy to detect 

 than that which is so apparent on the maturing gills of C. comatus 

 and C. atramentarius, but it is of precisely the same kind and has 

 the same significance. 



At 8 P.M. on the day before a pileus expands, the basidia and 

 paraphyses can clearly be distinguished from one another in the 

 hymenium, but the basidium-bodies of both the long and the short 

 basidia have not as yet developed any sterigmata or spores (Fig. 16, 

 A, p. 22). These come into existence during the ensuing night, 

 and the spores ripen during the early hours of the next day. As the 

 spores ripen, the increase in the amount of the dark pigment 

 deposited in their walls causes the pileus as a whole to become grey. 

 As soon as the spores are ripe, the pileus rapidly expands, thus 

 permitting of their liberation. 



The Opening of the Pileus. — The pilei of each diurnal crop of 

 fruit-bodies open almost simultaneously during the morning hours. 

 The process of spore-discharge is commenced as soon as the pileus 

 has become flattened and, while spores are still being liberated, the 

 pileus often becomes somewhat re volute. Photographs illustrating 

 some successive stages in the expansion of the pileus are shown in 

 Figs. 3-5. In Fig. 3 (p. 7) the stipes are still rapidly elongating 

 at their apices, the pilei are still conico-cylindrical, and the spores 

 on the gills are now black, thus giving the pilei their grey appear- 

 ance. In Fig. 4 (p. 8), which shows the same fruit-bodies an horn- 

 later than Fig. 3, the stipes have now grown to nearly their full 

 length, the pilei are rapidly expanding, the spores are ripe, and 

 spore-discharge is about to begin. In Fig. 5 (p. 10), which shows 

 the same fruit-bodies some three and a half hours later than Fig. 4, 

 ^ These Researches, vol. i, 1909, pp. 71-74, Figs. 27 and 28. 



