PANAEOLUS CAMPANULATUS 301 



from the apex downwards and so allow their seeds to escape in 

 succession. A gradual dispersion, as opposed to a simultaneous 

 one, seems to result in a greater chance of wide distribution for 

 the spores or seeds of any individual plant, owing to the fact that 

 external conditions, such as the direction of the wind, rain-fall, 

 presence of animals, etc., are constantly changing. Now let us 

 suppose that the basidia of the first generation of a fruit-body of 

 Panaeolus campanulatus were to begin the development of their 

 sterigmata at exactly the same time. Then, for eight hours after- 

 wards, no spores would be shed. Then, suddenly, millions of 

 spores would be liberated simultaneously. Let us further suppose 

 that the basidia of the second and of all the succeeding generations 

 were to develop synchronously. Then spore-discharge would take 

 place as follows : millions of spores of the first generation set free 

 simultaneously ; then a pause of about eight hours ; then millions 

 of spores of the second generation set free simultaneously ; then 

 another long pause ; and so forth. The irregular wave-method 

 of hymenial development leads to an avoidance of this inter- 

 mittency in spore-discharge. In nature, a fruit-body of Panaeolus 

 campanulatus liberates spores gradually from the first moment 

 of spore-discharge until its close. So many spores are set free 

 each minute for from seven to ten days. The never-ceasing stream 

 of spores which pours out from beneath the pileus during the 

 whole period of spore-discharge is directly traceable to the lack 

 of synchrony in the development of the numerous hymenial areas. 



Upon a single gill of Panaeolus campanulatus there are between 

 500,000 and 1,000,000 basidia, the number varying according to 

 the size of the pileus. An arrangement whereby all these basidia 

 would begin and end their development exactly simultaneously for 

 all of the series of generations into which they are divided would 

 necessarily be complex. The protoplasm of the gill would require 

 to act as a very perfect unit, the whole controlling each small part 

 of the hymenium, if such perfect unison of development were to 

 be attained. The physiological arrangements for the production 

 of successive generations of basidia are perhaps more easy to carry 

 out, i.e. require much less correlation of the protoplasmic mechanism 

 involved, when numerous small areas of the hymenium can act 



