195 



points staked out on ollur rin^s shows that in some seasons the 

 rings advance only a few centiineters. Growth is much slower 

 than reported by Dr. Bayliss* in Enj^land for fairy rin^s of Maras- 

 mius oreades and Clilocybe giiuinlea, where radial increase was 

 from 6 to 12 inches annually. No doubt some of the rings pro- 

 duced by Tricholoma praemagnum are from one to two centuries 

 old. 



Fig. 2. Fairy Ring cut near one edge bj^ a road. Knowing the age of the 

 road the calculation is made that this ring does not increase radially more than 

 I dm. a year. The light-colored vegetation in that part of the ring away from 

 the road is Artemisia frigida. 



The sporophores of the mushroom usually appear abundantly 

 in August or early September following a period of rainy weather, 

 but some may be found after rains in July or June or even May. 

 In many seasons there are so few sporophores produced at any 

 one time that no mushroom rings are apparent. Although, as 



* Bayliss, Jessie D., Observations on Marasmius oreades and Clilocybe gigantea 

 as Parasitic Fungi. Journal of Economic Biologj-, 6: part 4, pp. 111-132, 1911. 

 (A reprint of this article was kindly loaned the writer by Professor George D. Fuller 

 of the University of Chicago.) 



