Oct. 29,1917 
Fungus Fairy Rings 
203 
rather commonly in the short-grass vegetation and form rings marked 
by a stimulated area or by the occurrence of the fruiting bodies. The 
rings are usually small, seldom exceeding 6 to 10 meters. 
RINGS WHICH PRODUCE NO NOTICEABLE EFFECT ON THE NATURAL 
VEGETATION 
A single ring formed by Lepioia morgani Pk. was noted in the bunch- 
grass vegetation near Yuma, Colo. (PI. 26,B; 27,C). The ring, approxi¬ 
mately 24 meters in diameter, was composed of about 63 fruits (fig. 7). 
No effect could be noted on the vegetation. It is possible, however, that 
if this fungus had developed on the hard land in the short-grass cover, 
the effect would have been more noticeable. 
Pig. 6.—A bisect of a ring sketched in figure 5. In the case of Calvatia cyathiformis the distribution of the 
mycelium can scarcely be detected in the soil. The stimulated zone lies just inside the zone of fruiting 
bodies. 
DISTRIBUTION OF FAIRY RIN.GS 
Fairy rings occur for the most part in grass lands, but have been 
recorded in many cases in forests. Most of the investigators refer to 
them as having been formed in grassy areas and marked by the more 
luxuriant growth of grasses. The following authors discuss rings in this 
type of vegetation: Bradley (1717, p. 122-123) Hutton (1790), Wollaston 
(1807), Dutrochet (1834, 1837, P* 179-181), De Candolle (in Way, 1847), 
Way (1847), Westerhoff in 1859 (mRitzema Bos, 1901), Berkeley (i860), 
p. 41), Jorden (1862), Cooke (1866), Lees (1869), Buckman (1870), Gil¬ 
bert (1875), Kuperus (1876), Lawes, Gilbert, and Warington (1883), 
Van Tieghem (1884, p» 1044-1045), Sorauer (1886, p. 270-272), Treichel 
(1889), Olivier (1891), McAlpine (1898), Coville (1897, 1898), Atkinson 
(1900), Williams (1901), Ritzema Bos (1901), Beille (1904, p. 380-381), 
Baillion (1906), Molliard (1910), Massart (1910), Bayliss (1911), Munch 
(1914), and Ramaley (1916). 
The following dealt with fairy rings in forests or about trees: Tulasne 
and Tulasne (1851, p. 157-158), Stahl (1900, p. 666-667), Thomas (1905), 
Ludwig (1906), Reed (1910), and Coulter, Barnes, and Cowles (1911, 
p. 807). 
Dutrochet (1837, p. 179-181) called attention to the fact that rings 
develop most commonly on prairies that are not very fertile and where 
