i68 RESEARCHES ON FUNGI 



its alimentary canal so that, in the end, its faeces— deposited several 

 days later in various places in the pasture — will be thickly sown with 

 hundreds of thousands, or even millions, of Pilobolus spores. Owing 

 to (1) the very efhcient way in which the sporangia are discharged 

 and fixed to herbage, (2) the large number of the sporangia and still 

 larger number of the spores often produced ^on a single dung-plat, 

 and (3) the high probability that sporangia attached to herbage will 

 be swallowed sooner or later by a herbivorous animal, it is not 

 surprising that Pilobolus is so successful in maintaining its existence 

 in pastures and often flourishes there in such great abundance. 



Pilobolus gives to flowering plants and herbivorous animals 

 nothing in return for their services in dispersing its spores. However, 

 although Pilobolus does not pay for what it receives, it imposes on 

 the organisms which assist it a burden which is so light as to be 

 practically negligible. 



