Midsummer's Eve (June 20), the eve of the Summer Solstice, has traditionally been a magical time. One fascinating bit of medieval Midsummer magic involved ferns, the seeds of which were thought to be invisible and collectible only on Midsummer's Eve. In Bohemia, girls spread white cloths under the ferns to catch the seed. In Russia, after you caught the fern-seed in a basket, you could command the devil to give you the key to buried treasure. And after the Church changed Midsummer Night's Eve to St. John's Eve, you were supposed to stack twelve pewter plates under a fern (one for each apostle). When the seed fell, it passed through the plates until it came to rest on one. Which one? If you knew, you could pocket the fern seed and become invisible, too-a trick that Shakespeare mentions in his play, A Midsummer Night's Dream.

In addition to rendering folks invisible, ferns were traditionally used in ointment for cuts and bruises, in liniment for aching joints, and in tea to ease indigestion.