FALCK'S THEORY 223 



that millions and millions of spores, which otherwise might never 

 be dispersed, are as a matter of fact spread far and wide over fields 

 and woods. 



If effective convection currents were given off by fruit-bodies, 

 then, doubtless, they might be increased by the presence of maggots 

 in the pileus and stipe. From this point of view the presence of 

 these animals in the sporophores of Amanita rubescens, &c., might 

 be of occasional advantage ; but it seems to me that, from the 

 data at our disposal, we are not yet justified in assuming a symbiotic 

 relationship between flies and Agarics. 



We have now seen how easily the spores may be conveyed away 

 from the fruit-bodies by air-currents. The wind, when travelling 

 several miles an hour, must frequently carry the spores from a 

 fruit-body for very long distances. Owing, however, to their steady 

 fall at the rate of 0*5-5 mm. per second, sooner or later all spores 

 must reach the earth. The larger the spores, the sooner will 

 they settle. The big spores of many species of Coprinus will not 

 be carried on the average so far as the smaller spores of the Mush- 

 room or of Collybia dryophila. With the ultimate fate of the 

 spores after they have once settled we are not here concerned. 



