258 



RESEARCHES ON FUNGI 



and therefore the beginning of the development of intermediate 

 areas on the hymenium, is indicated by slight shading. 



FIG. 90. Panaeolus campanulatus. Part of the hymenium on the side of a gill, 

 showing spores only, sketched with the help of a camera lucida on the first clay 

 of spore-discharge. The dotted lines have been added in order to enable the 

 eye to distinguish more readily the black, white, and intermediate areas from 

 one another. There are waves of development from a to 6 and from c to d. 

 In the intermediate areas, the spores (shaded with dots) are turning from 

 brown to black. The area shown = O'l square mm. Magnification, 300. 



When two waves of development approach each other from 

 opposite directions, the appearance of the hymenium may be like 

 that shown in Fig. 89. Here two waves of development are 

 advancing to the middle of the area from what we may call the 

 south-east and north-west respectively. Although in the central 

 black area all the spores are equally black, the ripest spores are 



