Viscum
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 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 shrubs 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 which perform some photosynthesis, 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, white, yellow, orange, or red when mature, containing one or more seeds embedded in very sticky juice; the seeds are dispersed when birds 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 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.
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, the Czech Republic.
Species
112 species are accepted.Viscum acaciae Viscum album – European mistletoeViscum ambongoense Viscum angulatum Viscum apiculatum Viscum articulatum Viscum bagshawei Viscum bancroftii Viscum bandipurense Viscum birmanicum Viscum boivinii Viscum calcaratum Viscum calvinii Viscum capense – Cape mistletoe Viscum capitellatum Viscum ceibarum Viscum chyuluense Viscum coloratum – Korean mistletoe Viscum combreticola Engl. – combretum mistletoeViscum congdonii Viscum congolense Viscum continuum Viscum coursii Viscum crassulae Viscum cruciatum – red-berried mistletoeViscum cuneifolium Viscum cylindricum Viscum decaryi Viscum decurrens Viscum dielsianum Viscum diospyrosicola Viscum dryophilum Viscum echinocarpum Viscum engleri Viscum exiguum Viscum exile 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 loranthicola Viscum luisengense Viscum macrofalcatum Viscum malurianum Viscum menyharthii Viscum meyeri Viscum minimum Viscum monoicum 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 pentanthum Viscum perrieri Viscum petiolatum Viscum radula Viscum ramosissimum Viscum rhipsaloides Viscum roncartii Viscum rotundifolium L.f. – round-leaved or red-berry mistletoeViscum sahyadricum Viscum schaeferi 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