Mistletoe

Few of our native plants have such an extensive and tangled mythology as the mistletoe, Viscum album. Reduced to a tiny sprig dangling forlornly from the light shade at Christmas time, this plant was in times past a powerfully magical symbol, only an echo of which now survives.
The plant is a semi-parasite, with roots that invade the body of larger woody plants to access minerals and water. Unlike fully parasitic plants it does photosynthesise, so is not dependent on the host for all its needs. In Europe this species lives happily on some 200 species of tree, although we tend to associate it with orchards. In Oxford there is a wonderful colony infesting the trees next to Magdalen Bridge, visible only after the leaves have fallen in autumn. The image is of a young plant growing conveniently low down on a small Sorbus near my house. The leaves, leathery and yellow-green, are paired on whippy stalks, with small clusters of the sticky, gelatinous berries in the axils. In overall habit the plant makes a decorative ball of foliage - a few years ago I bought an entire plant instead of the usual sprig, and was amazed by the intricacy of the 70cm ball of leaves and berries that arrived. It also looked much bigger in the house than it had in the market.

And so to mythology...

A magical plant as far back as the Ancient Greeks, mistletoe was thought to be the Golden Bough of Aeneas, the ancestor of the Romans. In early Christian tradition it had once been a tree, but the timber for Christ's cross was hewn from a mistletoe, since when the plant has been reduced to a withered parasite clinging to others, presumably as a punishment for allowing itself to be put to this use by the Roman soldiers. With a reputation for immortality mistletoe held, in Ancient Britain, a central role in the Druidical rites celebrating the winter solstice.

Finally its use as a Christmas decoration, which must have some connection to the midwinter ceremonies of the Druids. Though only recorded as far back as the 18th century, the use of mistletoe in the home still has shreds of earlier mythologies adhering to it - the mistletoe should not be allowed to touch the ground after harvesting, for instance. Originally the greenery would be kept in the house until Candlemas in early February, although other traditions have it hanging throughout the year as a preventative measure against fire and lightning strike (something akin to the old country practice of growing house-leeks on the roof) before being replaced the following Christmas Eve.