A MUSHROOM PARASITIC O.V AXOTIIER ]\IUSIIROO:\r. 129 



There is another interesting feature in connection with this 

 JStropharia parasite on Coprinns. This rehites to the struggle 

 for existence of Stropharia epimyces or its ancestors, which at 

 one time undoubtedly grew on dead organic matter in the soil 

 under conditions where it would come in competition with others 

 of the same life habit, as Coprinus atramentarius. In the strug- 

 gle between the two for food in the same substratum the Copri- 

 nus would seem to have had the advantage, while tlie Stropharia 

 being driven from the dead organic substratum, the connnon pos- 

 session of both, had adapted itself to grow as a parasite on its 

 former competitor. In this closer and more intimate struggle 

 the Stropharia has overcome the individuals of the Coprinus 

 which it attacks, though its existence is rendered precarious be- 

 cause of its being entirely dependent on the Coprinus host. 



This success of the Stropharia in this intimate competition 

 with Coprinus is also interesting in view of the suggestion by 

 ]\rassee in his Monograph of Coprinus* that the genus Coprinus 

 represents a very primitive group of the agarics from which the 

 others have descended, the four groups in the following order: 

 First, the black or purple brown spored agarics (Melanosporse), 

 second, the ochre or ochre brown spored (Ochrosporse) ; third, the 

 pink or salmon spored (Rhodosporse), and fourth, the white 

 spored agarics (Leucosporae). In the struggle for existence the 

 later appearing groups have had the advantage over the earlier 

 appearing ones because of a more specialized structure, better 

 means for distribution of spores, greater number of species, etc., 

 thus the Melanosporse succeeded the Coprina^, the Ochrospora^, 

 the Melanosporee, the Rhodosporfe, the Ochrospora\ and the Leu- 

 cospome the Rhodospora?. According to ^lassee wherever mem- 

 bers of any two of these groups come into competition, it is the 

 later one in time of evolution which succeeds. If this were so 

 it would be expected then that wherever any member of the 

 agarics other than the Coprinse come in competition with a mem- 

 ber of this group by reason of a similarity of life habit, tlie Co- 



*Massee, G.. A Revision of the Genus Coprinus. Ann. Bot.. 10: 123- 

 184, pis. 10, 11, 1896. 



