TORREYA 



September, 1916. 

 Vol. 16 No. 9 



MUSHROOM FAIRY RINGS OF TRICHOLOMA 

 PRAEMAGNUM 



By Francis Ramaley 



During a number of seasons the author has been interested in a 

 large mushroom that forms "fairy rings" in the dry grassland of 

 open mountain parks. The rings were first noticed at Tolland, 

 Colorado, near the mountain laboratory of the University of 

 Colorado. Later they were seen at other points within a radius 

 of 20 miles, namely: at Eldora, Sulphide, Nederland, Rollinsville, 

 Pine Glade, Pactolus, Crescent and Plainview. All of these 

 points lie between 6,000 and 9,000 feet in altitude. 



The rings were first noticed and photographed in 1909 but the 

 mushroom' was not carefully examined until 1912, when it was 

 recognized as a Tricholoma, although no specific determination 

 could be made. On the appearance of Vol. 10, part i, of the 

 North American Flora* with Murrill's account of that part of the 

 Agaricales to which Tricholoma belongs, the plant was identified 

 for me by Dr. L. O. Overholts now of Pennsylvania State College, 

 as Tricholoma praemagnum Murrill.f The type cited by the 

 author of the species was * ' collected on the crumbling walls of an 

 old sod house in Saskatchewan, Canada." The description also 

 notes that specimens were "collected on high land under sage- 

 brush, near Gunnison, Colorado." No mention is made of pro- 

 duction of fairy rings or semicircles or crescents. 



* North American Flora. Vol. 10, part i, p. 12, 1914. The plant is described a? 

 Melaneleuca praemagnum. Murrill has also used the name Tricholoma praemag- 

 num in Mycologia, 6: 269. 19 14. 



t Overholts, L. O. A re-description of Tricholoma praemagnum (in this issue of 

 Torreya). 

 [No. 8, Vol. 16, of ToRREY.\, comprising pp. 177-192, was issued 22 August, 1916] 



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