ECOLOGY OF FUNGI 177 



into pieces of the required size, and indiscriminately mixed 

 before being placed in the beds. In due course two of 

 the beds yielded an excellent crop of mushrooms, and 

 judging from the method of preparation of the beds, as 

 described above, all should have yielded an equally good 

 crop ; but such was not the case. In one of the unprofit- 

 able beds a strange toadstool appeared, which proved to 

 be Volvaria gloiocephala, a pink-spored species. The first 

 specimens of this intruder were removed, nevertheless it 

 spread with amazing rapidity throughout the bed, and 

 although a few small mushrooms appeared here and there, 

 not a single marketable specimen was produced by the 

 bed. In the second unprolific bed, Clitocybc nebularis, 

 a white-spored toadstool, soon took possession, and no 

 examples of the mushroom reached full growth. In both 

 instances the mushroom proper was undoubtedly present 

 in sufficient abundance to yield a good crop, but was 

 simply stamped out by a better fighter. I have never 

 observed, nor seen a case reported where a mushroom bed 

 has been swamped by a species of Coprinus, belonging to 

 the black-spored group of Agarics. As Coprinus grows 

 normally and in immense quantities on manure heaps, it 

 would at first sight have been expected that such fungi 

 would have been the chief transgressors. 



A probable explanation of the above is as follows. The 

 Agarics are divided primarily into five groups depending 

 on the colour of the spores, black, purple, brown, pink, 

 white. I have elsewhere endeavoured to prove that the 

 black-spored group is the oldest in time, and that the 

 sequence of evolution of the groups is from black to 

 white, the most modern group, in the order given. The 

 only evidence in support of this idea bearing on the 



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