Oct. 29, 1917 
Fungus Fairy Rings 
193 
I know that similar circles have been observed by naturalists, and by them ascribed 
to thunder; as we should certainly have done in this case, were it not for the regular 
annual progression, which, if the effect of thunder, must follow rules not yet investi¬ 
gated, either in electricity, vegetation, or the mineral system. 
He examined the soil and found no clue. At times he also noticed 
the presence of fungi in the ring, but did not consider them significant. 
Withering (1796, p. 222) definitely assigned the cause of fairy rings 
to Agaricus oceades. 
I am satisfied that the bare and brown, or highly cloathed and verdant circles, 
in pasture fields, called Fairy Rings , are caused by the growth of this Agaric. . . . 
Where the ring is brown and almost bare, upon digging up the soil to the depth of 
about 2 inches, the spawn of the Fungus will be found, of a greyish white colour, 
but where the grass has again grown green and rank, I never found any of the spawn 
existing. 
FUNGI CAUSING FAIRY RINGS 
The tendency of all fungi to grow outward from the point of germina¬ 
tion of the spore results in circular colonies in a widely varying group of 
fungi. Rings are often noted among the molds. This paper deals only 
with rings formed by Basidiomycetes. 
The first fairy rings noted which were definitely assigned to fungi 
were caused by Agaricus oceades. Following this report many different 
species were associated with fairy rings. 
Eleven years later Wollaston (1807) extended Withering’s observa¬ 
tions and reported rings formed by Agaricus campestris , A. terreus, A „ 
procerus , and Lycoperdon bovista. Most of the writers following Wollas¬ 
ton have substantiated his results with the exception of the following: 
Persoon (1819, p. 4-5) called attention to the singular distribution of 
mushrooms in fairy rings, but stated that the cause was not well known. 
Tees (1869) attributed the cause of these rings to the action of moles. 
The burrows of these animals were supposed to be marked by the dead 
area in the fairy ring. Buckman (1870) believed that the fungi appeared 
as the result of the stimulation and death of the vegetation, and were 
not therefore the primary cause, although the ring was often continued 
and extended by them; in fact, he thought that rings to which fungi 
had not become attached soon broke up and disappeared. Gillet 
(1874, P* 22) states that it is difficult to explain the cause of the grouping 
of some species of mushrooms in fairy rings. Although it is understood 
that most of the writers thought that one species of fungus alone was 
the cause of a particular fairy ring, only a few writers stated so definitely. 
Greville (1828, p. 323) said that he never detected more than one species 
of fungus in the same ring. This statement was also made by McAlpine 
(1898). Williams (1901, p. 207) stated that fairy rings 
showed a similar disposition to encourage the more luxuriant growth of other species 
of fungi that occurred elsewhere in the surrounding field. 
In eastern Colorado the fairy rings were never known to have more 
than one species in the fruiting zone, although a ring of Calvatia cyathi- 
formis was seen in fruit that had smaller rings of Agaricus campestris 
also in fruit, in the inside (fig. 9). 
