268 RESEARCHES ON FUNGI 



Rates of Development of Successive Generations of Basidia on a Gill of 



Panaeolus campanulatus. 



After the seventh generation of basidia had been produced, 

 the hymenium was practically exhausted, and no further develop- 

 ment took place. However, a few basidia were still left undeveloped. 

 Perhaps under more favourable conditions of existence these might 

 have given rise to yet another generation of spores. 



The number of basidial generations actually observed as coming 

 up in succession on the same small area of gill-surface was seven. 

 The total number, including those unobserved, must have been 

 more than this. The fruit-body was taken for observation when 

 it had already been shedding spores for some 24 hours. Supposing 

 that we reckon that the early unobserved generations took about 

 as long to go through their cycle as the first one observed, i.e. 

 about 8 hours, we must add at least two further generations to the 

 seven actually observed. If, too, we suppose that the few basidia 

 left at the end, under more favourable conditions of growth, would 

 have produced one more final generation, we should have a total 

 of ten generations altogether. 



We may therefore conclude that any one small area of the 

 hymenium of Panaeolus campanulatus, in the course of its develop- 

 ment, produces about ten generations of basidia which come to 

 maturity and shed their spores in succession. 



When the original black area was first focussed, it possessed 

 a peculiar contour of its own. The question may be asked : did 



