An immense deal of legendary lore has clustered round the so-called fairy-rings—­little circles of a brighter green in old pastures—­within which the fairies were supposed to dance by night.  This curious phenomenon, however, is owing to the outspread propagation of a particular mushroom, the fairy-ringed fungus, by which the ground is manured for a richer following vegetation.[6] Amongst the many other conjectures as to the cause of these verdant circles, some have ascribed them to lightning, and others have maintained that they are produced by ants.[7] In the “Tempest” (v. i) Prospero invokes the fairies as the “demi-puppets” that: 

  “By moonshine do the green sour ringlets make,
  Whereof the ewe not bites; and you, whose pastime
  Is to make midnight mushrooms.”

And in the “Merry Wives of Windsor” (v. 5) Mistress Quickly says: 

  “And nightly, meadow-fairies, look, you sing,
  Like to the Garter’s compass, in a ring;
  The expressure that it bears, green let it be,
  More fertile-fresh than all the field to see.”

Drayton, in his “Nymphidia” (1. 69-72), tells how the fairies: 

  “In their courses make that round,
  In meadows and in marshes found,
  Of them so called the fayrie ground,
  Of which they have the keeping.”

These fairy-rings have long been held in superstitious awe; and when in olden times May-dew was gathered by young ladies to improve their complexion, they carefully avoided even touching the grass within them, for fear of displeasing these little beings, and so losing their personal charms.  At the present day, too, the peasant asserts that no sheep nor cattle will browse on the mystic patches, a natural instinct warning them of their peculiar nature.  A few miles from Alnwick was a fairy-ring, round which if people ran more than nine times, some evil was supposed to befall them.

It is generally agreed that fairies were extremely fond of dancing around oaks, and thus in addressing the monarch of the forest a poet has exclaimed: 

  “The fairies, from their nightly haunt,
  In copse or dell, or round the trunk revered
  Of Herne’s moon-silvered oak, shall chase away
  Each fog, each blight, and dedicate to peace
  Thy classic shade.”

In Sweden the miliary fever is said by the peasantry to be caused by the elf-mote or meeting with elves, as a remedy for which the lichen aphosus or lichen caninus is sought.

The toadstools often found near these so-called fairy-rings were also thought to be their workmanship, and in some localities are styled pixy-stools, and in the North of Wales “fairy-tables,” while the “cheeses,” or fruit of the mallow, are known in the North of England as “fairy-cheeses.”