Mistletoe

Mistletoe
European mistletoe attached to a silver birch
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Santalales
Families
Santalaceae (Viscaceae) Loranthaceae Misodendraceae

A Mistletoe is a parasitic plant on the branches of a tree or shrub. All mistletoes are parasitic plants in the order Santalales. In the plant kingdom, parasitism evolved only nine times; of those, the parasitic mistletoe habit has evolved independently five times: 1) Misodendraceae, 2) Loranthaceae, 3) Santalaceae (formerly considered the separate family Eremolepidaceae), and Santalaceae (formerly treated as the separate family Viscaceae). Although Viscaceae and Eremolepidaceae were placed in a broadly-defined Santalaceae by APG2, these two mistletoe lineages have independent origins, according to DNA sequences analysed by Dan Nickrent, Southern Illinois University.

The name was originally applied to Viscum album (European Mistletoe, Santalaceae; the only species native in Great Britain and much of Europe); subsequently it was extended to other related species, including Phoradendron serotinum (the Eastern Mistletoe of eastern North America, also Santalaceae). European Mistletoe is readily recognized by its smooth-edged oval leaves in pairs along the woody stem, and waxy white berries in dense clusters of 2-6 together. In America, the Eastern Mistletoe is similar, but has shorter, broader leaves and longer clusters of ten or more berries together. The mistletoe commercially harvested in the US for Christmas decorations is Phoradendron flavescens.

The largest family of Mistletoes is Loranthaceae with 73 genera and over 900 species. . Some of these species have small, insect-pollinated flowers (as with Santalaceae), but others have spectacularly showy, large, bird-pollinated flowers. 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 host trees, and can eventually prove fatal to them where infestation is heavy, though damage more commonly only results in growth reduction. Viscum album can parasitise more than 200 tree and shrub species. Almost all mistletoes are hemiparasites, bearing evergreen leaves that carry out some photosynthesis on their own, and relying on the host mainly for water and the mineral nutrients it carries. An exception is the leafless quintral, Tristerix aphyllus, which lives deep inside the sugar-transporting tissue of a spiny cactus, appearing only to show its tubular red flowers. The genus Arceuthobium (dwarf mistletoe; Santalaceae) has reduced photosynthesis; as an adult, it manufactures only a small percentage of the sugars it needs from its own photosythesis but as a seedling it actively photosynthesizes until a connection to the host is established.

Most mistletoes seeds are spread by birds, such as the Mistle Thrush in Europe, the Phainopepla in southwestern North America, and Dicaeum of Asia and Australia; they derive sustenance through eating the fruits (drupes). The seeds are egested in their droppings and stick to twigs, or more commonly the bird grips the fruit in its bill, squeezes the sticky coated seed out to the side, and then wipes its bill clean on a suitable branch. The seeds are coated with a sticky material called viscin (containing both cellulosic strands and mucopolysaccharides), 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, for dung and Tang for branch, 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 species, 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 seeds. The dense evergreen witches' brooms formed by the dwarf mistletoes (Arceuthobium species) of western North America also make excellent locations for roosting and nesting of the Northern Spotted Owls and the Marbled Murrelets. In Australia the Diamond Firetails and Painted Honeyeaters are recorded as nesting in different mistletoes. This behavior is probably far more widespread than currently recognized; 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. A study of mistletoe in junipers concluded that more juniper berries sprout in stands where mistletoe is present, as the mistletoe attracts berry-eating birds, which also eat juniper berries; juniper berries that have passed through a bird's digestive tract are less likely to remain imprisoned within a hardened outer capsule. Such 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.

Kissing under the mistletoe

Nowadays, mistletoe is commonly used as a Christmas decoration, though allusions to mistletoe as a Christmas green were rare into the eighteenth century. Viscum album is used in Europe whereas Phoradendron serotinum 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. The custom is British rather than Scandinavian in origin.

According to custom, the mistletoe must not touch the ground between its cutting and its removal as the last of Christmas greens at Candlemas; mistletoe might remain hung through the year, often to preserve the house from lightning or fire, until it was replaced the following Christmas Eve.. The tradition has spread throughout the English-speaking world but is largely unknown in the rest of Europe. The appearance and nature of the fruit's content (viscin) is very similar or suggestive of human semen and this has strengthened its pagan connections.

Using the mistletoe to kiss under has even become incorporated into various holiday songs. The 1943 song I'll Be Home for Christmas tells the story of a lonely traveler looking forward to coming home and seeing, among other things, mistletoe. The Mistletoe is mentioned in the song "Chestnuts roasting on an open fire" (Christmas Song), made famous by Nat King Cole, and written by Mel Torme. The song "Holly Jolly Christmas" sung by Burl Ives, and used for the TV special "Rudolph the Red Nosed Reindeer", features the line, "Ho Ho, the Mistletoe", and the line, "Kiss her once for me". In 1961 singer Aretha Franklin released a Christmas song called Kissin' by the Mistletoe. In 1971 singer Lynn Anderson recorded the song Mr. Mistletoe on her holiday album The Christmas Album. The song talks about an elf who hangs mistletoe in homes so that people can "steal a kiss from someone that they know". In 2001 Barbra Streisand released the song It Must Have Been the Mistletoe.

In culture and mythology

Mistletoe figured prominently in Norse mythology: the god Baldur was killed with a weapon made of mistletoe. Mistletoe bears fruit at the time of the Winter Solstice, the birth of the new year, and may have been used in solstitial rites in Druidic Britain.

In Celtic mythology and in Druid rituals, it was considered an antidote to poison, but it is now known that the fruits of many mistletoes are poisonous if ingested, as they contain viscotoxins.

A Christian tradition says that mistletoe was once a tree, and furnished the wood of the Cross. After the Crucifixion, the plant shriveled and became dwarfed to a parasitic vine.[1]

In Romanian traditions, mistletoe (vâsc in Romanian) is considered a source of good fortune. The medical and the supposed magical properties of the plant are still used, especially in rural areas.

Mistletoe has sometimes been nicknamed the vampire plant because it can probe beneath the tree bark to drain water and minerals, enabling it to survive during a drought. William Shakespeare gives it an unflattering reference in Titus Andronicus, Act II, Scene I: "Overcome with moss and baleful mistletoe".

Mistletoe is the state floral emblem for the State of Oklahoma. The state did not have an official flower, leaving the Mistletoe as the assumed state flower until the Oklahoma Rose was designated as such in 2004.

In a popular myth, confusing Mistletoe and the Holly 'holy' Tree, the most sacred tree of the Druids, it is said that Mistletoe was cut with a gold sickle and it lost its power if it fell and touched the ground. The confusion arises from both plants being green all year and both having colorful fruits as well as sharing similar history concerning the winter months.

Other uses

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.[2] [3]. 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. [4] [5]

The sticky juice of mistletoe berries was used as adhesive to trap small animals or birds.

Images

• 
  Mistletoe in an apple tree in Essex, England
• 
  Mistletoe in an apple tree in Essex, England
• 
  Mistletoe bush on a eucalyptus tree
• 
  Mistletoe attached to eucalyptus host
• 
  Mistletoe fruits
• 
  The sticky seed of the mistletoe on a branch
• Red mistletoe, New Zealand
  Red mistletoe, New Zealand
• 
  Mistletoe in San Bernardino Mountains

External links

• About mistletoe
• Parasitic Plant Connection. See families Misodendraceae, Loranthaceae, Santalaceae, and Viscaceae
• Introduction to Parasitic Flowering Plants by Nickrent & Musselman
• Mistletoe phylogenetics; 2000 WIFDWK pdf by Nickrent
• Encyclopedia of Life Sciences 2001 pdf by Nickrent
• Phoradendron serotinum images at bioimages.vanderbilt.edu
• More Information