24 RESEARCHES ON FUNGI 



that the last stages in the development of a fruit-body of C. curtus, 

 which include the development of the spores, the elongation of the 

 stipe, the expansion of the pileus, the discharge of the spores, and 

 the autodigestion of the gills, can be carried through just as well in 

 darkness as in the light. 



The culture was kept in the dark. On the second day, under 

 these conditions, another crop of fruit-bodies appeared on the 

 dung ; but the stipes elongated only slightly instead of fully, while 

 the pilei failed to develop their spores, remained foxy-red instead 

 of turning grey, and did not expand. 



On the morning of the third day in the dark, the crop of fruit- 

 bodies just described, which under normal conditions of light would 

 have opened on the second day, still remained imperfect. Their 

 stipes had elongated somewhat more, but not fully ; while all the 

 pilei were still foxy-red, sporeless, and unexpanded. 



About 11 o'clock in the morning of the third day, the culture 

 was taken out of the dark-room and placed by a window in strong 

 diffuse daylight. In the afternoon, the crop of fruit-bodies which 

 should have opened on the second day were still unchanged and, 

 subsequently, they withered away without producing and shedding 

 any spores. The light, however, was having a more favourable 

 effect on the rudimentary fruit-bodies which were present in con- 

 siderable numbers at the surface of the dung-balls. 



In the morning of the fourth day, the culture having been 

 exposed to daylight for 24 hours, more than one hundred new fruit- 

 bodies came to perfection. Their stipes elongated, their pilei 

 turned grey and expanded, and they shed their spores and under- 

 went autodigestion in a perfectly normal manner. This was 

 evidently due to the action of the daylight of the previous day on 

 the rudimentary fruit-bodies which were then present at the surface 

 of the dung. 



From the series of observations just recorded we may draw the 

 following conclusions. In Coprinus curtus daylight gives a morpho- 

 genic stimulus to the rudimentary fruit-bodies of such a kind as to 

 enable them to elongate their stipes, ripen their spores, expand their 

 pilei, and shed their spores. If fruit-bodies have previously received 

 light daily, on the day of expansion they do not require any light 



