Oct. 89,1917 
Fungus Fairy Rings 
207 
(Fulton, 1906). This may be due to chemotropic stimulation or to the 
more obvious fact that food material or water is usually more abundant 
in the new soil. The high content of ammonia and nitrates in the soil 
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Fig. 9 .—A ring formed by Calvatia cyathiformis, almost complete and 65 meters in diameter. The ring 
contained 50 fresh fruiting bodies and had apparently produced an earlier crop of 54 puffballs. This 
ring occurred in an area in which a great number of small rings produced by Agaricus compestris were 
found. These rings seem to have interrupted the Calvatia rings at all points except on the upper right- 
hand side. At no place is there evidence that the C. cyathiformis displaced A. campestris, although a 
possible condition of this kind is indicated on the upper right-hand portion of the figure. This ring was 
mapped northeast of Yuma, Colo., on June 29 , 1916 . It should be noted that, although Calvatia and 
Agaricus fruited abundantly in the region about Yuma and on the Wray Divide in 1916 , no fruiting 
bodies were produced at Akron. The records in Table II are for the vicinity of Akron and are not general 
for the whole eastern portion of the State. 
occupied by the older portion of the mycelium may also play a part. 
That rings do not continue when they come in contact with each other 
has been noted repeatedly. The inside of large rings of one species is 
often occupied with many smaller rings of another species (fig. 9), and 
7769°—17-2 
