68 RESEARCHES ON FUNGI 



pilei began to expand, the stipes ceased to grow toward the window, 

 but instead grew vertically upwards. On the right side of Fig. 25 is 

 shown the same group of fruit-bodies as on the left after twelve 

 hours' further development. By comparing the figures, the change 



FIG. 25. Copnnua nivcus. Adjustments of the pileus in space. The fruit-bodies 

 grown on horse dung received unilateral illumination from a window. The 

 young stipes, as shown on the left, made heliotropic curvatures. On the right 

 the fruit-bodies are twelve hours older than on the left. As soon as the pilei 

 began to expand, the stipes, in response to a geotropic stimulus, grew vertically 

 upwards. Stages in the raising of the pileus by elongation of the stipe, and in 

 the expansion, auto-digestion, and rolling up of the pileus are also to be seen. 

 Natural size. 



which took place in the direction of growth of the stipes may be 

 readily realised. 



The expansion of the pileus separates the gills from one another, 

 and causes the hymenium to look downwards in a manner similar to 

 that described for Coprinus plicatilis. Here, again, the gills do 

 not require to adjust themselves in vertical planes by means of a 

 geotropic stimulus. The part played by the ' : deliquescence " of the 

 gills and the folding of the pileus rim over the top of the pileus 



