THE COPRINUS TYPE OF FRUIT-BODY 



21 



points of difference between the two types may be tabulated as 



follows : — 



For each fruit-body the five facts are correlated and only find 

 their full significance in reference to each other. 



Doubtless, within certain limits, there has been a tendency for 

 the survival of those fruit-bodies which produce and successfully 

 liberate the maximum number of spores with the least expendi- 

 ture of fruit-body substance and energy. In both our types this 

 desideratum has been met in part by the production of central 

 tubular stipes, symmetrical radiate pilei, closely packed basidia, 

 tiny spores, and a much folded hymenium situated on the plate- 

 like gills. Further arrangements, however, in the two types 

 present marked differences. 



In the Mushroom, adjacent basidia on any part of a gill 

 mature successively and shed their spores as soon as these are 

 ripe (cf. Plate I., Fig. 3). Every square millimetre of hymenial 

 surface on each gill, therefore, sheds a certain number of spores 

 each minute throughout the entire spore-liberating period of the 

 fruit-body. This necessitates that sufficient space shall be provided 

 between adjacent gills throughout their whole length by the time 



