COPRINUS CURTUS 



31 



K iTc 



if-^ 



short. Its actual length was found to range from about thirty- 

 minutes in very small fruit-bodies to about three and a half hours 

 in very large fruit-bodies. ^ 



If an expanding pileus is taken from a fruit-body growing in a 

 closed crystallising dish about • 5-1 

 hour before spore-discharge would 

 normally begm, and if the pileus is 

 then turned upside down and placed 

 in a closed compressor cell (c/. Fig. 

 103 in Vol. Ill, p. 240), spore-dis- 

 charge commences almost at once 

 and soon becomes very active. 

 Preparations of this kind have often 

 been used in the Winnipeg labora- 

 tory for the purpose of demonstrat- 

 ing spore-discharge to students. 

 Upon looking down on an inverted 



pileus for a few minutes with the 



low power of the microscope, one 



may observe hundreds of spores 



as they are shot away from their 



sterigmata and fall through the air 



back on to the hymenium. The 



hastening of the beginning of the 



spore-discharge period may be due 



to the temporary exposure of the 



pileus to the relatively dry air of 



the laboratory. 



Just before a spore is discharged 



from its sterigma, a drop of fluid 



is excreted in the same manner as 



in all other Hymenomycetes (Fig. 



20, C), and it was in Coprinus curtus that I first saw the drop- 



excretion phenomenon in 1911. Several times, immediately after 



a spore had been shot upwards from a gill lying on a slide under 



1 For a detailed account of the length of the spore -discharge period in Coprinus 

 curtus, vide these Researches, vol. ii, 1922, p. 99. 



Fig. 20. — Coprinus curtus. Spores 

 and their discharge. A, the top 

 of a spore, to show the germ- 

 pore. B, a spore on its sterigma, 

 to show its projecting hilvun 

 just above the sterigma. C, a 

 similar spore which has just 

 excreted a drop of fluid from 

 its hilum. D, a spore which 

 was shot witli its drop into the 

 air from a gill and fell back on 

 to the gill with the drop still 

 attached. E, a basidium with 

 two paraphyses; the sterigma 

 a has just discharged its spore 

 in the direction shown by the 

 arrow ; the drop is travelling 

 with the spore. F, the same as 

 E, but a few seconds later : the 

 sterigma a has excreted a new 

 drop. Usually no such drop is 

 excreted. Magnification, 293. 



