COPRINUS PLICATILIS 49 



removed from a lawn and set in a horizontal position, the end of 

 the stipe soon turns the pileus upwards, thus bringing it once more 

 into the optimum position for shedding its spores. During this 

 reaction, one may observe geotropic swinging, just as in Coprinus 

 curtus.^ 



The Periodicity in Fruit-body Development and Time of Spore- 

 discharge. — Whilst studying Coprinus plicatilis as it occurred on 

 a lawn in my father's garden at King's Heath, England, I observed 

 that, day after day during the summer and early autumn, new 

 fruit-bodies made their appearance in a rhythmical manner. Early 

 in the morning, after a dewy night, very young fruit-bodies could 

 be seen springing up here and there on the turf. Soon the pilei 

 began to expand, and spore-discharge took place at midday or 

 very early in the afternoon. Late in the afternoon the fruit-bodies 

 withered. Not once, although these observations were repeated 

 during several successive years, did I ever have reason to suppose 

 that pileus-expansion and spore-discharge took place at night. 



The periodicity in fruit-body development and spore-discharge 

 in Coprinus plicatilis resembles that of C. curtus, described in the 

 last Chapter. It is doubtless due to the diurnal changes of light 

 and darkness ; and it may well be that in C. plicatilis, just as in 

 C. curtus, the final development of each fruit-body is dependent 

 on a morphogenic stimulus given by light to the rudiment of the 

 fruit-body during one or more days preceding the day the pileus 

 expands and liberates its spores. 



The Ripening and Discharge of the Spores and the Absence of 

 Autodigestion. — During their development, the gills of Coprinus 

 plicatilis, like those of C. comatus, C. atramentarius , and all other 

 Coprini, darken in colour from below upwards (Fig. 33). This 

 field observation and other observations made with the microscope 

 on freshly-gathered developing fruit-bodies have convinced me 

 that in C. plicatilis the spores on each gill ripen from below upwards. 

 By the time that pilear expansion begins, the gills are uniformly 

 black, owing to all the spores having become fully pigmented. As 

 soon as the expansion of the pileus (Fig. 25, p. 42) has been 

 completed, spore-discharge begins. 



1 Vide these Researches, vol. i, 1909, pp. 65-67, Fig. 24. 



VOL. IV. E 



