Trees have always been important in the lives of men, especially those, like the Celts, who lived in Europe at a time when it was largely covered with forests. Trees were worshiped and killing a tree could be the same as killing an animal. (There are myths in which oaks give shrieks or groans when they are felled.) Many trees were thought to be inhabited by tree-spirits, which gradually came to be regarded as Gods.
In particular, two of these are important in Norma. The oak tree was worshiped all over Europe. The Greeks held it sacred to Zeus and the Romans to Jupiter. Since trees are frequently struck by lightning, the Germans dedicated the oak to Thor, the thunder-god. Nothing was more sacred to the Celts of Gaul than the mistletoe which grows on oaks. Since the mistletoe remains green in the winter, they thought the oak spirit moved into the mistletoe leaves as a safe place during the cold.
Irminsul is a Teutonic and Norse concept. In one of his few mistakes, Romani moved it from Germany to Gaul. (He had it right in his 1821 La Sacerdotess d'Irminsul.) The Germans believed that the universe was supported by a giant tree and set up single pillars, made by stripping the limbs off a tree, on hilltops. The most famous, and sacred, one was at Eresburg in what is now Westphalia. In 772, it was destroyed by a Charlemagne during an expedition against the Saxons to whom it was an object of great veneration. He destroyed their 'heathen' idol in attempting to convert them to Christianity. Similar columns were later erected to the hero Roland and to Thor.
Mistletoe (All-Healer or Golden Bough) has always been the subject of myth. It was thought to be to its host tree as the soul is to the body. Common on many trees, it is rarely found on oaks. Thus it is specially sacred when found there, but is revered almost everywhere on earth. Surprisingly, since the berries are poisonous, it has been used as medicine by many cultures. Aeneas carried it on his descent into the underground. The Aino of Japan regarded as medicinal, Africans carried it into war to prevent wounds, in France it was believed to be an antidote for poison. (While it is true that its juice helps lower blood pressure, and crushed leaves relieve pain, don't try it on your own.) Sprays have been hung on cradles to protect infants from fairies, and twigs have been used as divining rods to find treasure. It was used to protect against witchcraft and evil spirits. In many places it was thought to promote fertility in both people and animals. The Norse associated it with Freya, the goddess of love, beauty and fertility. If a sprig was given to the first cow calving after New Year it would protect the entire herd. American Indians used it for toothache, measles and dog bites. It is the state flower of Oklahoma.
One story, that of Balder, Odin's son, is especially important in Norse mythology. When Balder had a dream which forebode his death, the gods decided to save him. The goddess Frigg (Fricka) took an oath from all earthly things, vegetable and mineral that they would not hurt Balder. The only one she didn't ask was the mistletoe because she thought it too young to swear. Loki found this out, made a dart of a mistletoe twig and had it thrown at Balder, killing him. "And that was the greatest misfortune that ever befell gods and men." His body was placed on a funeral pyre on his ship and burned.
Mistletoe is only a partial parasite. It has roots and can live in the ground using photosynthesis. However, it is most commonly found on trees; the roots burrow into the bark and drain its nourishment, eventually starving the host to death. The Latin name of American mistletoe, Phoradendron serotinum, means tree thief. The seeds are eaten by birds and deposited on trees either by wiping their beaks or through their droppings. (The name itself is Anglo-Saxon: Mistel = dung, tan = twig.) It then starts grow in six weeks, taking five years to flower.
It was believed that mistletoe was good as medicine as long as it was collected on the first day of the moon, without the use of iron, and not allowed to touch the ground. The Swiss shot it down with an arrow. Swedes shot or knocked it down with stones. Pliny the Elder described the Celtic custom:
The Druids...have nothing more sacred that the mistletoe and the tree that bears it, providing it is an oak....They consider everything that grows on those trees to be sent from Heaven and see in it a sign of the election of the tree by the god himself. Mistletoe of this species is very rarely found and when it is discovered it is picked with great religious pomp; this must be done on the sixth day of the moon, which for them marks the beginning of the months, years and centuries, which last for thirty years; this day is chosen because the moon is already strong without being a half-course. In their language they call [mistletoe] 'that which cures all'. According to the rites, they prepare a sacrifice with religious festivities at the foot of the tree and bring two white bulls whose horns are tied for the first time. A priest, dressed in white, climbs into the tree, cuts the mistletoe with a golden sickle* and places it on a white tunic. They then immolate the victims, praying to the god to make his gift propitious for those to whom he has granted.
Natural History, XVI, 249-251
The practice of kissing under the mistletoe may go back to the time it was held to be so sacred that enemies who happened to meet beneath it had to lay down their arms until the next day. When done correctly today, the man removes one berry after the kiss. When all the berries are gone, there is to be no more kissing.
*Gold is so soft it wouldn't cut the tough mistletoe twig. The sickle was probably gilded bronze or even iron.