Mistletoe
Mistletoe is a plant parasitic on the branches of a tree or shrub.  All mistletoes are parasitic plants in the order Santalales.  This 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. .
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 serotinum (the Eastern Mistletoe of eastern North America, also Santalaceae). The 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 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 trees, and can eventually prove fatal to them where infestation is heavy, though damage more commonly only results in growth reduction. All mistletoes are hemiparasites, bearing evergreen leaves that carry out some photosynthesis on their own, relying on the host mainly for water and the mineral nutrients it carries. 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 (e.g. the Mistle Thrush in Europe, the Phainopepla in southwestern North America, and Dicaeum of Asia and Australia), which 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 stands 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, 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) 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. . 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.

# 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. . 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  .
Mistletoe figured prominently in Norse mythology (which some believe is the origin of 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 previous times the tradition was that the couple took away a fruit each time until they were all used up and at this point the mistletoe lost its vitality. 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. Mistletoe also bears fruit at the time of the Winter Solstice (the birth of the new year) and may have been used in a fertility rite in Ancient Britain.  The fertility rite may be a more likely source of the 'kissing under the mistletoe' tradition which originated from Britain rather than Scandinavia, but the pagan ritual was maybe brought into Britain by the Saxons, who worshipped the same gods as Norsemen. The tradition has spread throughout the English speaking world but is largely unknown in the rest of Europe.
Christian beliefs combined with existing pagan feasts and winter rituals to create many long-standing traditions of Christmas celebrations. For example, ancient Europeans believed that the mistletoe plant held magic powers to bestow life and fertility, to bring about peace, and to protect against disease. Northern Europeans associated the plant with the Norse goddess of love, Freyja, and developed the custom of kissing underneath mistletoe branches. Christians incorporated this custom into their Christmas celebrations, and kissing under a mistletoe branch eventually became a part of secular Christmas tradition.
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.
In Romanian traditions, mistletoe (vasc 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.  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 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.
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.
- Mistletoe in an apple tree in Essex, England
Mistletoe in an apple tree in Essex, England
- Mistletoe in an apple tree in Essex, England
Mistletoe in an apple tree in Essex, England
- Mistletoe bush on a eucalyptus tree
Mistletoe bush on a eucalyptus tree
- Mistletoe attached to eucalyptus host
Mistletoe attached to eucalyptus host
- Mistletoe fruits
Mistletoe fruits
- The sticky seed of the mistletoe on a branch
The sticky seed of the mistletoe on a branch
- Red mistletoe, New Zealand
Red mistletoe, New Zealand
- Mistletoe in San Bernardino Mountains
Mistletoe in San Bernardino Mountains