Mistletoe
From Wikipedia, the free encyclopedia
| iMistletoe | ||||||||
|---|---|---|---|---|---|---|---|---|
 European mistletoe attached to a poplar
|
||||||||
| Scientific classification | ||||||||
|
||||||||
|
|
||||||||
Mistletoe is the common name for various parasitic plants in the order Santalales, belonging to the families Santalaceae, Loranthaceae and Misodendraceae. The species in Santalaceae were formerly commonly treated in a separate family Viscaceae.
The name was originally applied to Viscum album (European Mistletoe, Santalaceae; the only species native in Great Britain and much of Europe), and subsequently to other related species, including Phoradendron leucarpum (the Eastern Mistletoe of eastern North America, also Santalaceae). In an example of convergent evolution, several less related but superficially very similar plants in the Loranthaceae are also so similar that they have also been called mistletoes.
The European Mistletoe is readily recognised by its smooth-edged oval leaves in pairs along the woody stem, and waxy white berries in dense clusters of 2-6 together. American Mistletoe is similar, but has shorter, broader leaves and longer clusters of ten or more berries together.
Mistletoe biodiversity is markedly higher in subtropical and tropical climates; Australia has 85 species, of which 71 are in Loranthaceae, and 14 in Santalaceae.
The species grow on a wide range of trees, and can eventually prove fatal to them where infestation is heavy, though damage more commonly only results in growth reduction. Most mistletoes are only partial parasites, bearing evergreen leaves that carry out some photosynthesis of their own, relying on the host mainly for mineral nutrients from the ground. The genus Arceuthobium (dwarf mistletoe; Santalaceae) has dispensed with even this, becoming a total parasite relying on its host plant for photosynthesis as well as nutrients.
Most mistletoes are spread by birds (e.g. the Mistle Thrush in Europe, and the Phainopepla in southwestern North America) which eat the berries. The seeds are excreted in their droppings and stick to twigs, or more commonly the bird grips the fruit in its bill, squeezing the sticky coated seed out to the side, and then wiping its bill clean on a suitable branch. The seeds are coated with a sticky gum, viscin, which hardens and attaches the seed firmly to its future host.
The word 'mistletoe' is of uncertain etymology; it may be related to German Mist, another word for dung, but Old English mistel was also used for basil.
While historically often considered a pest that kills trees and devalues natural habitats, mistletoe has recently become recognized as an ecological keystone, an organism that has a disproportionately pervasive influence over its community. A broad array of animals depend on mistletoe for food, consuming the leaves and young shoots as well as transferring pollen between plants and dispersing the sticky fruits. The dense evergreen clumps also make excellent locations for roosting and nesting, with species ranging from Northern Spotted Owls, Marbled Murrelets, Diamond Firetails and Painted Honeyeaters recorded nesting in different mistletoes. This behaviour is probably far more widespread than currently recognised; more than 240 species of birds that nest in foliage in Australia have been recorded nesting in mistletoe, representing more than 75% of the resident avifauna. These interactions lead to dramatic influences on diversity, as areas with greater mistletoe densities support higher diversities of animals. Thus, rather than being a pest, mistletoe can have a positive effect on biodiversity, providing high quality food and habitat for a broad range of animals in forests and woodlands worldwide.
[edit] Uses and mythology
The leaves and young twigs are the parts used by herbalists, and it is popular in Europe, especially in Germany, for treating circulatory and respiratory system problems, and cancer [1] [2]. Mistletoe is being studied as a potential treatment for tumors. Although such use is not yet permitted in the U.S., Mistletoe is prescribed in Europe [3] [4].
Mistletoe figured prominently in Norse mythology (whence the modern Western custom of kissing under bunches of it hung as holiday decorations). The god Baldur was killed with a weapon made of mistletoe. In Celtic mythology and in Druid rituals, it was considered an antidote to poison, but contact with its berries produces a rash similar to the poison ivy rash in people who are sensitive to it (as many are), so the whole plant came to be thought of as poisonous.
In Romanian traditions, mistletoe (vâsc in romanian) is considered as a source of good fortune. The medical and the supposed magical properties of the plant are still used, especially in rural areas. This custom is inherited from Dacians.
Mistletoe has sometimes been nick-named the "vampire plant" because it can probe beneath the tree bark to drain water and minerals, enabling it to survive during a drought (see vampirism). William Shakespeare gives it an unflattering reference in Titus Andronicus, Act II, Scene I: "Overcome with moss and baleful mistletoe"
Nowadays, mistletoe is commonly used as a Christmas decoration. Viscum album is used in Europe whereas Phoradendron leucarpum is used in North America. According to a custom of Christmas cheer, any two people who meet under a hanging of mistletoe are obliged to kiss.
Mistletoe was the official flower for the State of Oklahoma until 2004 when it was replaced by the Oklahoma Rose. Mistletoe however still serves as the state's official floral emblem.
 Mistletoe bush on a eucalyptus tree |
 Mistletoe attached to eucalyptus host |
 Mistletoe seeds |
 The sticky fruit of the mistletoe on a branch |
 Red mistletoe, New Zealand |
