Why do we use mistletoe at Christmas?
Dr Michael ParkinsonMistletoe is an unusual plant in that the mature plant doesn't have any roots, but parasitises, or lives off, another plant and uses that plant for support and for water and minerals.
Rather than roots, it produces a 'spike' called a haustorium, which pushes its way into the host plant and plumbs itself into the plant's water supply. This doesn't usually harm the host plant that much, and mistletoe seeds are nowadays deliberately 'planted' on a host tree to grow and sell at Christmas.
The white fruits are eaten by birds and the seeds may be seen in bird droppings. They are sticky and will stick to a growing tree. The name mistletoe may therefore have come from the Anglo-Saxon word 'Mistel', meaning 'dung', and 'Tang' for 'branch'. Which is not very romantic at all!
In ancient times, a plant growing without roots must have been seen as a true marvel, and invested with magical properties. Mistletoe is probably the 'golden bough' which has been associated with magic since ancient times. Small wonder then that mistletoe was used in Druid ceremonies, being mentioned by the Roman, Pliny the Elder.
It is rarely found growing on oak, which was the most sacred tree to the Druids, so a mistletoe plant growing on an oak must have been especially rare, and was seen as invested with special supernatural powers.
AND KISSING UNDER THE MISTLETOE?
Since pagan times, mistletoe has been associated with fertility rites, with boughs of mistletoe hung to ward off evil spirits and promote fertility. Kissing under the mistletoe is a natural extension of this.
It may also have come from Norse mythology and Scandinavian custom. In the legend of Baldur and Loki, a mistletoe spear was used to kill Baldur. After this it was decreed that mistletoe would forever bring love in to the world not death.
Although folklore states that mistletoe is good for romance, don't eat the berries. They are poisonous! We now know that mistletoe contains a variety of toxic chemicals, such as phenylpropanoids and lectins, and extracts of mistletoe have a number of pharmacological properties including stimulation of the immune system and direct toxic effects on tumour cells. It has been used in various forms to treat cancer, epilepsy, infertility, menopausal symptoms, nervous tension, asthma, hypertension, headache, and dermatitis.
Modern interest in mistletoe as an anti-cancer treatment began in the 1920s. Reports of more than 30 clinical studies of mistletoe as a treatment for people with cancer have been published since the early 1960s. However, the evidence is conflicting and the jury is still out on whether it works or not.
Q Dr Michael Parkinson (pictured below at Mount Teide, Tenerife) is a lecturer in the School of Biotechnology in Dublin City University, and chair of the BSc in horticulture.