''Viscum'' is a genus of over 100 species of

mistletoe Mistletoe is the common name for obligate parasite, obligate parasitic plant, hemiparasitic plants in the Order (biology), order Santalales. They are attached to their host tree or shrub by a structure called the haustorium, through which they ...

s, native to temperate and tropical regions of

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

and

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

. Traditionally, the genus has been placed in its own family

Viscaceae Viscaceae is a taxonomic family name of flowering plants. In this circumscription, the family includes the several genera of mistletoes. This family name is currently being studied and under review as in past decades, several systems of plant tax ...

, but recent genetic research by the

Angiosperm Phylogeny Group The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships disc ...

shows this family to be correctly placed within a larger circumscription of the

sandalwood Sandalwood is a class of woods from trees in the genus ''Santalum''. The woods are heavy, yellow, and fine-grained, and, unlike many other aromatic woods, they retain their fragrance for decades. Sandalwood oil is extracted from the woods. Sanda ...

family,

Santalaceae The Santalaceae, sandalwoods, are a widely distributed family of flowering plants (including small trees, shrubs, perennial plants, perennial herbs, and epiphyte, epiphytic climbersHewson & George t al.'Santalaceae'' taxonomy, 1984, pp. 191-1 ...

. Its name is the origin of the English word

viscous Viscosity is a measure of a fluid's rate-dependent resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for example, syrup h ...

, after the Latin ''viscum'', a sticky bird lime made from the plants' berries. They are woody, obligate hemiparasitic

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

s with branches long. Their hosts are woody shrubs and

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

s. The foliage is dichotomously or verticillately branching, with opposite pairs or whorls of green

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

which perform some

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

(minimal in some species, notably ''V. nudum''), but with the plant drawing its mineral and water needs from the host tree. Different species of ''Viscum'' tend to use different host species; most species are able to use several different host species. The

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are inconspicuous, greenish-yellow, diameter. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

is a

berry A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit although many pips or seeds may be present. Common examples of berries in the cul ...

, white, yellow, orange, or red when mature, containing one or more

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s embedded in very sticky juice; the seeds are dispersed when

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s (notably the

mistle thrush The mistle thrush (''Turdus viscivorus'') is a bird common to much of Europe, Palearctic, temperate Asia and North Africa. It is a year-round resident in a large part of its range, but northern and eastern populations bird migration, migrate s ...

) eat the fruit, and remove the sticky seeds from the bill by wiping them on tree branches where they can germinate.

Toxicity in the genus ''Viscum''

''Viscum'' species are poisonous to humans; eating the fruit causes a weak pulse and acute gastrointestinal problems including stomach pain and

diarrhea Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...

. At least one of the active ingredients is the

lectin Lectins are carbohydrate-binding proteins that are highly specific for sugar Moiety (chemistry), groups that are part of other molecules, so cause agglutination (biology), agglutination of particular cells or precipitation of glycoconjugates an ...

viscumin, which is intensely toxic. It inhibits protein synthesis by catalytically inactivating

ribosomes Ribosomes () are macromolecular machines, found within all cells, that perform biological protein synthesis (messenger RNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA molecules to fo ...

. In spite of this, many species of animals are adapted to eating the fruit as a significant part of their diet. David M. Watson, "Mistletoe-A Keystone Resource in Forests and Woodlands Worldwide" ''Annual Review of Ecology and Systematics'' 32 (2001:219–249).

Fossil record

†''Viscum morlotii'' from the early

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

, has been described from

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

leaf compressions that have been found in the Kristina Mine at

Hrádek nad Nisou Hrádek nad Nisou (; , ) is a town in Liberec District in the Liberec Region of the Czech Republic. It has about 8,000 inhabitants. The historic town centre is well preserved and is protected as an urban monument zone. Administrative division Hr� ...

North Bohemia North Bohemia (, ) is a region in the north of the Czech Republic. Location North Bohemia roughly covers the present-day NUTS regional unit of ''CZ04 Severozápad'' and the western part of ''CZ05 Severovýchod''. From an administrative perspec ...

, the

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

Species

Viscum coloratum on Aspen about Khabarovsk Russia

112 species are accepted. * '' Viscum acaciae'' * ''

Viscum album ''Viscum album'' is a species of mistletoe in the family Santalaceae, commonly known as European mistletoe, common mistletoe, or simply as mistletoe (Old English ''mistle''). It is native to Europe as well as to western and southern Asia. ''V. al ...

'' – European

* '' Viscum ambongoense'' * '' Viscum angulatum'' * '' Viscum apiculatum'' * '' Viscum articulatum'' * '' Viscum bagshawei'' * '' Viscum bancroftii'' * '' Viscum bandipurense'' * '' Viscum birmanicum'' * '' Viscum boivinii'' * '' Viscum calcaratum'' * '' Viscum calvinii'' * ''

Viscum capense ''Viscum capense'' (common name, Cape mistletoe) is a species of Mistletoe that is indigenous to South Africa, especially the area from Cape Town, northwards along the coast up to Namibia, and eastwards as far as the Eastern Cape province. This ...

'' – Cape mistletoe (South Africa) * '' Viscum capitellatum'' * '' Viscum ceibarum'' * '' Viscum chyuluense'' * ''

Viscum coloratum ''Viscum'' is a genus of over 100 species of mistletoes, native to temperate and tropical regions of Europe, Africa, Asia and Australasia. Traditionally, the genus has been placed in its own family Viscaceae, but recent genetic research by the An ...

'' – Korean mistletoe (Korea) * '' Viscum combreticola'' Engl. – combretum mistletoe * '' Viscum congdonii'' * '' Viscum congolense'' * '' Viscum continuum'' * '' Viscum coursii'' * '' Viscum crassulae'' * ''

Viscum cruciatum ''Viscum cruciatum'', commonly called the red-berry mistletoe, is a species of mistletoe in the family Santalaceae. It is native to Lebanon, Morocco, Israel, Palestine, Portugal, Spain, and Syria Syria, officially the Syrian Arab Republic, ...

'' – red-berried mistletoe * '' Viscum cuneifolium'' * '' Viscum cylindricum'' * '' Viscum decaryi'' * '' Viscum decurrens'' * '' Viscum dielsianum'' * ''

Viscum diospyrosicola ''Viscum'' is a genus of over 100 species of mistletoes, native to temperate and tropical regions of Europe, Africa, Asia and Australasia. Traditionally, the genus has been placed in its own family Viscaceae, but recent genetic research by the An ...

'' * '' Viscum dryophilum'' * '' Viscum echinocarpum'' * '' Viscum engleri'' * '' Viscum exiguum'' * ''

Viscum exile ''Viscum exile'' is a species of mistletoe in the family Santalaceae. It is a parasitic plant native to Sulawesi. References External links''Viscum exile'' occurrence datafrom GBIF {{taxonbar, from=Q18082504 exile Exile or banishment is ...

'' * '' Viscum fargesii'' * '' Viscum fastigiatum'' * '' Viscum fischeri'' * '' Viscum goetzei'' * '' Viscum grandicaule'' * '' Viscum griseum'' * '' Viscum hainanense'' * '' Viscum hexapterum'' * '' Viscum heyneanum'' * '' Viscum hildebrandtii'' * '' Viscum hoolei'' * '' Viscum indosinense'' * '' Viscum iringense'' * '' Viscum itrafanaombense'' * '' Viscum junodii'' * '' Viscum katikianum'' * '' Viscum liquidambaricola'' * '' Viscum littorum'' * '' Viscum longiarticulatum'' * '' Viscum longipetiolatum'' * '' Viscum lophiocladum'' * ''

Viscum loranthi ''Viscum'' is a genus of over 100 species of mistletoes, native to temperate and tropical regions of Europe, Africa, Asia and Australasia. Traditionally, the genus has been placed in its own family Viscaceae, but recent genetic research by the An ...

'' * '' Viscum loranthicola'' * '' Viscum luisengense'' * '' Viscum macrofalcatum'' * '' Viscum malurianum'' * '' Viscum menyharthii'' * '' Viscum meyeri'' * '' Viscum minimum'' * ''

Viscum monoicum ''Viscum'' is a genus of over 100 species of mistletoes, native to temperate and tropical regions of Europe, Africa, Asia and Australasia. Traditionally, the genus has been placed in its own family Viscaceae, but recent genetic research by the An ...

'' * '' Viscum multicostatum'' * '' Viscum multiflorum'' * '' Viscum multinerve'' * '' Viscum multipedunculatum'' * '' Viscum myriophlebium'' * '' Viscum mysorense'' * '' Viscum nepalense'' * '' Viscum nudum'' * '' Viscum obovatum'' * '' Viscum obscurum'' * '' Viscum oreophilum'' * '' Viscum orientale'' * '' Viscum ovalifolium'' * ''

Viscum pauciflorum ''Viscum'' is a genus of over 100 species of mistletoes, native to temperate and tropical regions of Europe, Africa, Asia and Australasia. Traditionally, the genus has been placed in its own family Viscaceae, but recent genetic research by the An ...

'' * '' Viscum pentanthum'' * '' Viscum perrieri'' * '' Viscum petiolatum'' * '' Viscum radula'' * '' Viscum ramosissimum'' * '' Viscum rhipsaloides'' * '' Viscum roncartii'' * ''

Viscum rotundifolium ''Viscum rotundifolium'', the red-berry mistletoe, is a variable, wide-ranging and monoecious mistletoe Mistletoe is the common name for obligate parasite, obligate parasitic plant, hemiparasitic plants in the Order (biology), order Santala ...

'' L.f. – round-leaved or red-berry mistletoe * '' Viscum sahyadricum'' * ''

Viscum schaeferi ''Viscum'' is a genus of over 100 species of mistletoes, native to temperate and tropical regions of Europe, Africa, Asia and Australasia. Traditionally, the genus has been placed in its own family Viscaceae, but recent genetic research by the An ...

'' * '' Viscum schimperi'' * '' Viscum scurruloideum'' * '' Viscum semialatum'' * '' Viscum songimveloensis'' * '' Viscum stenocarpum'' * '' Viscum subracemosum'' * '' Viscum subserratum'' * '' Viscum subverrucosum'' * '' Viscum taiwanianum'' * '' Viscum tenue'' * '' Viscum tieghemii'' * '' Viscum trachycarpum'' * '' Viscum triflorum'' * '' Viscum trilobatum'' * '' Viscum tsaratananense'' * '' Viscum tsiafajavonense'' * '' Viscum tuberculatum'' * '' Viscum verrucosum'' * '' Viscum vohimavoense'' * '' Viscum whitei'' * '' Viscum wrayi'' * '' Viscum yunnanense''

References

Other sources

Flora of China: ''Viscum''Flora of Pakistan: ''Viscum''Flora Europaea: ''Viscum''
*

{{Authority control Parasitic plants Santalaceae genera Taxa described in 1753 Taxa named by Carl Linnaeus