MISTLETOE: happily kissing under the dung branch

KISSING under the mistletoe at Christmas has been a tradition stretching back centuries but kissers are usually too preoccupied to wonder why this poisonous, parasitic shrub should symbolise peace and love.

In fact, there are several theories, some dating back to the Celtic Druids who were said to have used mistletoe's dark green leaves and sticky white berries in their ceremonies.

Two white bulls were traditionally sacrificed during a full moon in one of these rites to bring good luck to all the participants - although the bulls might have wanted their money back.

Mistletoe was thought to possess magical powers and the ability to ward off evil, making it a great healer of animosity between warring groups or individuals.

But mistletoe itself is anything but peaceful to the trees to which it attaches itself.

Unlike most shrubs, which draw their own water and nutrition from the soil, mistletoe sucks the life from any host tree after first drilling through the bark.

Although its appearance is slight and stringy compared to the tree itself, it grows fast and can live for a decade - weakening and causing the gradual decline of its host.

Oak, poplar and apple trees are particularly susceptible to attack. Mistletoe will also attach itself to birch, beech and plane trees, though the relative smoothness of their bark can defeat it.

Mistletoe is actually only partially parasitic as its leaves contain chlorophyll enabling it to photosynthesise and produce its own energy.

The name 'mistletoe' is said to spring from an ancient belief that this distinctive evergreen only grew in trees where birds left droppings. 'Mistel' is thought to be an old Anglo-Saxon word for dung while 'toe' is derived from another word to describe a twig or branch.

'Mistletoe', therefore, came to mean 'dung on a branch'. (Not the most helpful info for any partygoer trying to lure someone under a sprig during the festive season.)

Later, the development of botany led to the discovery that mistletoe could indeed be spread by seeds passed through birds' digestive systems.

So those initiators of ancient folklore were pretty observant.

Despite having a poisonous effect on humans, various birds enjoy mistletoe berries.

Mistle thrushes were apparently so named because they find them especially delicious.

The stickiness of the seeds mean they often become stuck to foraging birds' beaks before being wiped off on another tree, spreading mistletoe in a secondary way.

As a teenager, I once hovered hopefully beneath a sagging sprig of mistletoe clutching a glass of white wine at a party.

My luck was in.

I was soon targeted - unfortunately not by the beautiful hostess of the party but by her ugly friend.

It put me off mistletoe for life.