364 RESEARCHES ON FUNGI 



and will be deposited on the surrounding grass and other plants upon 

 which herbivorous animals feed. The greater the violence of dis- 

 charge, the more widely are the projectiles spread in pastures and 

 the more chance there is that, eventually, they will be swallowed by 

 herbivorous animals. (3) The adhesiveness of the exterior surfaces 

 of the projectiles enables the projectiles to remain attached to the 

 leaves and stems of grass-plants, etc., despite the weather, for long 

 periods of time until eventually herbivorous animals swallow them 

 with their substratum. (4) The positive heliotropism of the fungus 

 guns causes the guns to direct their apices toward the source of the 

 strongest incident rays of light and, therefore, in the end, to shoot 

 away their projectiles in directions least obstructed by obstacles. 

 The result of this is that the projectiles are distributed more widely 

 over the surrounding herbage than they otherwise would be and 

 therefore have a better chance of being swallowed by herbivorous 

 animals. (5) The multisporous nature of each projectile serves to 

 increase the mass of the projectile and thus to increase the distance 

 to which the projectile can be ejaculated. 1 The non-separation of 

 the spores in a projectile whilst the projectile is attached to grass, 

 etc., is in no way disadvantageous ; for the individual spores in a 

 projectile readily separate from one another and become dispersed 

 when the projectile is passing down the alimentary canal of a herbi- 

 vorous animal. (6) Finally, the occurrence of the gun-developing 

 fruit-bodies on dung is due to the fact that the projectiles, after 

 being shot away from the dung on to grass, etc., are eventually 

 swallowed by herbivorous animals. The spores pass unharmed 

 down the alimentary canal of horses, cattle, rabbits, etc., separate 

 from one another in the course of their journey, and so are deposited 

 in the solid excreta which the animals drop to the ground. In these 

 excreta the spores germinate and the mycelium so produced ulti- 

 mately gives rise to new gun-producing fruit-bodies. 



We therefore see that the guns and projectiles of Pilobolus, 

 Ascobolus immersus, and Sphaerobolus, although diverse in origin, 

 are beautifully adapted both by their structure and functions to 

 bring about dispersion of the spores through the agency of ( 1 ) flower- 

 ing plants, which are used as lodging places for the adhesive multi- 

 1 Cf. these Researches, Vol. I, 1909, p. 253. 



