282 RESEARCHES ON FUNGI 



from which the spore has been shot remains naked and quite devoid 

 of any trace of a liquid drop. However, an exception to this general 

 rule was observed in a fruit- body of Coprinus atramentarius which 

 had been kept in a very moist condition under a bell-jar during a 

 whole night. A gill was taken from this fruit-body and placed in a 

 closed compressor cell, and the zone of spore-discharge was watched 

 with the microscope in the usual way. It was then seen that a 

 number of sterigmata, directly after discharging their spores, began 

 to excrete liquid drops at their apices. These drops continued to 

 grow for about 10 seconds and then their growth entirely ceased. 

 This exceptional drop-excretion from the ends of sterigmata which 

 have just shot away their spores may have some bearing on the 

 explanation of the mechanism of spore-discharge. 



In the first volume of these Researches, I showed that the spores 

 of Psalliota cam.pestris, Marasmius oreades, and Polyporns squamosus 

 are shot forward in almost a straight line into the interlamellar 

 spaces to a distance of about • 1 mm. and that the horizontal 

 motion is very rapidly brought to an end owing to the resistance of 

 the air.i In still air, in consequence of this resistance and of the 

 attraction of gravitation, a spore, when nearing the end of its 

 horizontal flight, describes a sharp curve and falls vertically down- 

 wards. I have called this peculiar trajectory a sporahola.^ By 

 using methods already described,^ I have proved to myself that 

 the spores of Coprinus atramentarius have a trajectory similar to 

 that of the Mushroom and other Hymenomycetes, and that 

 the horizontal distance of discharge is of the order of 0-05 mm. 

 Unfortunately, an exact determination of this distance could not be 

 made owing to the limited time during which the living fruit-bodies 

 were at my disposal. On the assumption that 0-05 mm. is the 

 average horizontal distance of discharge of spores shot out per- 

 pendicularly from the hymenium, I have indicated the sporabolas 

 of a few spores in the zone of spore-discharge in the semi- diagram- 

 matic drawing reproduced in Fig. 122 (p. 287). It is certain that 

 the spores are shot forward to such a distance from the basidia 

 that they fall down somewhere near the middle of the interlamellar 



1 These Researches, vol. i, 1909, pp. 142, 185. 



2 Ibid, p. 185. ^ IbiiL, pp. 133-147. 



