Oct. 39, 1917 
Fungus Fairy Rings 
233 
figure 2 that only rings formed by A garicus tabularis could be found in 
the wheat field during 1916. These were noticeable because of the de¬ 
pression of the growth of the wheat. Those formed by C. cyathiformis 
could not be distinguished, since they had produced no effect on the 
crop. 
OTHER FUNGUS RINGS 
A garicus campestris, Calvatia polygonia , C. }ragilis, Catastoma sub - 
ierraneum (Pk.) Morg., Marasmius oreades, and Tricholoma melaleuca do 
not differ markedly from C. cyathiformis in their effect on the vegetation. 
Lepiota morgani occurred in a sandy soil in bunch-grass vegetation (Shantz, 
1911, p. 54). No effect was noted on the native cover, although a great 
number of fruits had been produced. 
GRAZING AND CULTIVATION 
An especially interesting effect is seen in areas which are grazed. The 
grass in the stimulated zone appears to be more palatable than the less 
luxuriant grass in the adjacent sod and this zone is therefore often easily 
distinguished by the closely cropped grass. 
Rings formed by Calvatia cyathiformis have not been found fruiting 
in cultivated fields. C. polygonia continues to fruit after land is culti¬ 
vated, several rings having persisted in fields which have been under cul¬ 
tivation for a period of five years. A garicus tabularis produces rings 
which seem to persist without injury under cultivation. The ring shown 
in the wheat field (PI. 14, C; 21, A) was on land which has been under 
continuous cultivation for the past seven years. These rings often fruit 
as well as in cultivated fields as in the native soil. 
CAUSE OF THE STIMULATED GROWTH 
Practically every investigator of fairy rings has noted a stimulated 
growth of the natural vegetation on fairy rings. This stimulation was 
attributed to the decay of the fungus fruits or mycelium by Wollaston 
(1807), Way (1847), Westerhoff in 1859 (in Ritzema Bos, 1901), Berkeley 
(i860), Jorden (1862), Gilbert (1875), VanTieghem (1884, p. 1044-1045), 
Olivier (1891), Stahl (1900), Ritzema Bos (1901), Beille (1904, p. 381), 
and Massart (1910). The principal constituents which contributed to 
this stimulation were potash, phosphated alkali, magnesia, and sulphate 
of lime, according to Way (1847), an d nitrogenous and mineral manuring 
according to Gilbert (1875). Westerhoff in 1859 (in Ritzema Bos, 1901) 
actually produced the stimulated growth of the vegetation by scattering 
over the surface mushrooms cut up into small pieces. Jorden (1862) 
attributed the stimulation to the fertilizing effect of the ammonia which 
the fungus absorbed from the atmosphere. Lawes, Gilbert, and War- 
ington (1883), and Ballion (1906), attributed the stimulation to the decay 
of fungus fruiting bodies and filaments and to the nitrates and residual 
products formed by the action of the mycelium on the organic matter of 
