Mistletoe the leaves and berries of the plant, with teas prepared from the plant being particularly dangerous. While adults may suffer little effect, these are more pronounced in small children and in animals. There are 1500 species of Mistletoe, varying widely in toxicity; the European Mistletoe ("Viscum Album") is more toxic than the American Mistletoe ("Phoradendron serotinum"), though concerns regarding toxicity are more prevalent in the US. Mistletoe has been used historically in medicine for its supposed value in treating arthritis, high blood pressure, epilepsy and infertility: Conversely, it can cause vasoconstriction and bradycardia, and is also used as an illegal
Common name nomenclature is a global system that attempts to denote particular organisms or taxa uniquely and , on the assumption that such organisms or taxa are well-defined and generally also have well-defined interrelationships; accordingly the ICZN has formal rules for biological nomenclature and convenes periodic international meetings to further that purpose. The form of scientific names for organisms that are called binomial nomenclature is superficially similar to the noun-adjective form of vernacular names or common names which were used by prehistoric cultures. A collective name such as "owl" was made more precise by the addition of an adjective such as "screech".