''Viscum'' is a genus of about 70–100 species of mistletoes, native to temperate and tropical regions of

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

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and

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologi ...

. 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 for us ...

family,

Santalaceae The Santalaceae, sandalwoods, are a widely distributed family of flowering plants (including small trees, shrubs, perennial herbs, and epiphytic climbersHewson & George t al.br>''Santalaceae'' taxonomy, 1984, pp. 191-194.) which, like other mem ...

. Its name is the origin of the English word

viscous The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

, after the Latin ''viscum'', a sticky

bird lime Birdlime or bird lime is an adhesive substance used in trapping birds. It is spread on a branch or twig, upon which a bird may land and be caught. Its use is illegal in many jurisdictions. Manufacture Historically, the substance has been prepa ...

made from the plants' berries. They are woody, obligate hemiparasitic shrubs 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, including only woody plants with secondary growth, plants that are ...

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

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

(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 A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s are inconspicuous, greenish-yellow, diameter. The

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

is a berry, white, yellow, orange, or red when mature, containing one or more

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

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

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s (notably the mistle thrush) 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, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

. At least one of the active ingredients is the lectin viscumin, which is intensely toxic. It inhibits protein synthesis by catalytically inactivating ribosomes. 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 preserved ...

leaf compressions that have been found in the Kristina Mine at

Hrádek nad Nisou Hrádek nad Nisou (; german: Grottau, pl, Gródek nad Nysą) is a town in Liberec District in the Liberec Region of the Czech Republic. It has about 7,700 inhabitants. The town centre is well preserved and is protected by law as an urban monument ...

in North Bohemia, the

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

Selected species

Viscum coloratum on Aspen about Khabarovsk Russia

* ''

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 and western and southern Asia. ''Viscum album ...

'' – European mistletoe * '' Viscum articulatum'' * '' Viscum bancroftii'' * '' Viscum capense'' – Cape mistletoe (South Africa) * '' Viscum coloratum'' – Korean mistletoe (Korea) * '' Viscum combreticola'' Engl. – combretum mistletoe * ''

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, Palestine, Portugal, Spain, and Syria Syria ( ar, سُورِيَا or سُورِيَ ...

'' – red-berried mistletoe * '' Viscum diospyrosicola'' * '' Viscum exile'' * '' Viscum fargesii'' * '' Viscum liquidambaricola'' * '' Viscum loranthi'' * ''

Viscum minimum ''Viscum minimum'' is a species of mistletoe in the family Santalaceae. It is a parasitic plant native to South Africa. Description In its native habitat ''Viscum minimum'' uses two species of succulents, ''Euphorbia polygona'' and ''Euphorbia ...

'' * '' Viscum monoicum'' * '' Viscum multinerve'' * '' Viscum nudum'' * '' Viscum orientale'' * '' Viscum ovalifolium'' * ''

Viscum rotundifolium ''Viscum rotundifolium'', the red-berry mistletoe, is a variable, wide-ranging and monoecious mistletoe Mistletoe is the common name for obligate hemiparasitic plants in the order Santalales. They are attached to their host tree or shrub ...

'' L.f. – round-leaved or red-berry mistletoe * '' Viscum scurruloideum'' * '' Viscum triflorum'' * '' Viscum whitei'' * '' Viscum yunnanense''

References

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

{{Taxonbar, from=Q147345 Parasitic plants Santalales genera