''Viscum'' is a genus of about 70–100 species of

mistletoe Mistletoe is the common name for obligate hemiparasitic plants in the order Santalales. They are attached to their host tree or shrub by a structure called the haustorium, through which they extract water and nutrients from the host plant. ...

s, 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 Angiosperm Phylogeny Group shows this family to be correctly placed within a larger circumscription of the sandalwood family, Santalaceae. Its name is the origin of the English word viscous, after the Latin ''viscum'', a sticky bird lime made from the plants' berries. They are woody, obligate hemiparasitic

shrub A shrub (often also called a 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 ...

s with branches long. Their hosts are woody shrubs and trees. The foliage is dichotomously or verticillately branching, with opposite pairs or whorls of green

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

which perform some photosynthesis (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 flowers are inconspicuous, greenish-yellow, diameter. The fruit 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 are strawberries, raspb ...

, white, yellow, orange, or red when mature, containing one or more seeds embedded in very sticky juice; the seeds are dispersed when birds (notably the

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

) 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. At least one of the active ingredients is the

lectin Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in rec ...

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 David M. Watson is an Australian ornithologist and ecologist who is also a scientific specialist on mistletoes. He served on the New South Wales Threatened Species Scientific Committee from 2015 until publicly resigning in June 2017 in protest ...

, "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, has been described from fossil leaf compressions that have been found in the Kristina Mine at Hrádek nad Nisou in

North Bohemia North Bohemia ( cs, Severní Čechy, german: Nordböhmen) 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 Severovýc ...

, the Czech Republic.

Selected species

Viscum coloratum on Aspen about Khabarovsk Russia

* '' Viscum album'' – European mistletoe * ''

Viscum articulatum ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

Viscum bancroftii ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

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. Th ...

'' – Cape mistletoe (South Africa) * ''

Viscum coloratum ''Viscum'' is a genus of about 70–100 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 ...

'' – Korean mistletoe (Korea) * ''

Viscum combreticola ''Viscum combreticola'', the Combretum mistletoe, is a leafless, dioecious mistletoe shrub, occurring from southern to tropical Africa, in a broad zone following the Rift Valleys. Though it is typically a hemiparasite of '' Combretum'' species, i ...

'' Engl. – combretum mistletoe * '' Viscum cruciatum'' – red-berried mistletoe * ''

Viscum diospyrosicola ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

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 is primarily pena ...

'' * '' Viscum fargesii'' * ''

Viscum liquidambaricola ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

Viscum loranthi ''Viscum'' is a genus of about 70–100 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 ...

'' * '' Viscum minimum'' * ''

Viscum monoicum ''Viscum'' is a genus of about 70–100 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 ...

'' * '' Viscum multinerve'' * ''

Viscum nudum ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

Viscum orientale ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

Viscum ovalifolium ''Viscum'' is a genus of about 70–100 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 ...

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

Viscum scurruloideum ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

Viscum triflorum ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

Viscum whitei ''Viscum'' is a genus of about 70–100 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 ...

'' * ''

Viscum yunnanense ''Viscum'' is a genus of about 70–100 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 ...

References

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

{{Taxonbar, from=Q147345 Parasitic plants Santalales genera