PANAEOLUS CAMPANULATUS 263 



The fruit-body made use of for study, before being removed 

 from the culture dish, had already been shedding spores for about 

 24 hours, so that, when it was first observed with the horizontal 

 microscope, it was beginning its second day of spore-discharge. 

 Its gills showed the usual mottling of lighter and darker areas so 



FIG. 92. The horizontal microscope of simple construction used for observing 

 the development of the hymenium in the area A of Fig. 91. About three- 

 fifths the actual size. 



characteristic for all species of Panaeolus. The gill watched with 

 the horizontal microscope, whilst under observation, was subjected 

 to conditions very similar to those in nature in that : (1) it had its 

 normal orientation in space, (2) it remained attached to the pileus, 

 and (3) it was surrounded with damp air at a medium temperature. 

 Under these conditions the gill continued its development, and for 

 three further days and nights continued to produce and liberate 

 spores. It thus became possible for me to follow the development 

 of one and the same piece of hymenium on a gill which was subjected 

 to normal conditions for a considerable period of time. 



