344 RESEARCHES ON FUNGI 



are shot away from their conidiophores by Empusa ^ and Ento- 

 mophthora, often to a distance of 1-2 cm. ; and single basidiospores 

 are shot away from their sterigmata by Uredineae to a distance of 

 0- 4-1-0 mm., and by Hymenomycetes to a distance usually of 

 0- 1-0-2 mm. Up to the present, no sound has ever been heard 

 when spore-discharge has been taking place from the fruit-bodies 

 of these fungi ; and the projectiles are so minute and their pro- 

 pulsion so feeble that, probably, for the unaided human ear, Empusa 

 and Entomophthora and all Uredineae and Hymenomycetes mil 

 for ever be silent plants. However, physicists have invented 

 microphones which magnify sounds very greatly ; and it is possible 

 that, with the aid of these instruments, the collective sound of the 

 simultaneous discharge of thousands of spores from a large fruit- 

 body of one of the Agaricaceae might be made audible. So far as 

 I know, no one has tested this possibihty as yet. The best fruit- 

 bodies to use with a microphone in a trial experiment would probably 

 be a large Coprinus, such as Coprinus comatus or C. sterquilinus, 

 which has large spores and discharges its spores only in the zones 

 of spore-discharge bordering upon the autodigesting edges of the 

 gills. A large fruit-body of Coprinus comatus shoots away from 

 its gill-edges about 1,000,000 spores a minute or more than 10,000 a 

 second, and it is just possible that a very sensitive microphone might 

 make the collective sound of these numerous discharges faintly 

 audible. 



Sounds Made by Fungus Guns are of No Biological Signifi- 

 cance. — Finally, it may be remarked that the sound given out by 

 fungus guns as they explode and the sound made when a fungus 

 projectile strikes some object are merely bye-products of the process 

 which has to do with the dispersion of the spores ; and, obviously, 

 they are neither of advantage nor of disadvantage to the fungi 

 concerned. While sounds are given out by, and are heard by, the 

 Higher Animals and some Lower Animals, so far as we know plants 

 never signal to one another by means of sound waves or respond 

 to sounds of any kind whatsoever. 



^ For a photograph sliowing how far the spores of Einpusa muscae are shot, 

 vide Vol. I, 1909, Fig. 83, p. 255. The magnification there given should have been 

 1-3 and not f. 



