PANAEOLUS CAMPANULATUS 265 



over the whole area. Most of the spores disappeared within half 

 an hour, and the whole area was cleared in an hour and a half 

 after the beginning of the observations. 



In consequence of losing its spores, the black area became a 

 white area. Whilst this change was going on, the surrounding 

 white area had been turning into a dark area, owing to the fact 

 that its spores, originally colourless, had begun to develop a brown 

 pigment. Thus the original colour scheme became reversed : the 

 black area surrounded by a white became converted into a white 

 area surrounded by a black. 



Now a little while before and also during the discharge of the 

 spores from the first generation of basidia observed on the black 

 area, a second generation of basidia could be distinguished rising 

 into prominence. These new basidia occupied positions in the 

 hymenium between the old ones and, in their totality, were similar 

 to the old ones both in number and distribution. When the 

 basidia of the first generation were discharging their spores, those 

 of the second had already attained their full body-length and 

 protruded to the maximum extent beyond the general level of the 

 hymenium. Moreover, they were developing their sterigmata. 

 For about forty-five minutes after the discharge of the spores of 

 a first-generation basidium, it was also observed that no trace 

 of spores could be perceived upon the sterigmata of the adjacent 

 second-generation basidia, but at the end of this time the spores 

 began to develop. About one hour and ten minutes after the 

 discharge of the old spores, the new ones were about half-grown 

 and, in the course of about another twenty minutes, they became 

 full-grown. After attaining full size, the new spores remained 

 colourless for some time in one carefully observed instance for 

 about an hour and a half. They then began to turn brown, and 

 they became black in about an hour and a half. Perhaps the 

 pigment still continued to accumulate for some time after this, 

 although no further blackening could be observed. After the 

 spores had turned black, they remained on the sterigmata for 

 about three hours and a half and were then discharged. 



If we date the second generation of basidia from the time of 

 discharge of the spores of the first generation, we may say that 



