PANAEOLUS CAMPANULATUS 277 



is clear : the number of past generations of basidia, which the 

 collapsed basidia really represent, is two. So far then, in classifying 

 our basidia, we have accounted for two past generations and the 

 present generation. We must now seek out the generations which 

 are coming or are still to come. 



What we may term the coming generation of basidia, i.e. those 

 basidia which will rapidly come to maturity and produce spores 

 immediately after the present generation of basidia has become 

 exhausted, can readily be made out. They are distinguished indi- 

 vidually from other young basidia by the fact that, unlike these, 

 they have attained their maximum diameter and have already 

 become protuberant. Eight of them are present in the area under 

 discussion and, in order to help the reader in finding them in 

 Fig. 94, A, they have been set out by themselves in Fig. 94, D. The 

 diameter of their bodies is equal to that of the bodies of the basidia 

 of the present generation. The only protuberant elements in the 

 hymenium are the basidia of the present and the coming generations. 

 In our area, the basidia of the coming generation have already 

 reached their maximum protuberancy, i.e. their bodies project above 

 the general surface of the hymenium just as far as those of the 

 basidia of the present generation. The basidia of the coming 

 generation are also densely filled with protoplasm which, so to speak, 

 is waiting to be put into the spores when these have been produced. 

 On the other hand, the basidia of the present generation are poor 

 in protoplasm owing to the fact that the transference of this sub- 

 stance to the reproductive bodies has already been partially or 

 completely accomplished. The basidia which are younger than those 

 of the present generation, like the latter, are full of protoplasm, 

 but their contents, owing to smaller volume, are much less con- 

 spicuous to the eye. In some areas similar to the present one, it 

 was found that, shortly before the spores of the present generation 

 of basidia are to be discharged, the sterigmata of the basidia of 

 the coming generation are in course of development. In the area 

 taken for our analysis, however, the sterigmata were not observed. 

 Probably the time had not yet come for their development. It may 

 be said that, when an area of the hymenium has begun to shed 

 spores, two generations of basidia are undergoing development 



