Mistletoe has long been the Christmas symbol of love, peace and goodwill, and is famed for its stolen-kisses power. American mistletoe, the kind most often associated with kissing, is just one of 1,300 species of the plant worldwide, but around twenty of these are endangered. In the past, mistletoe was often considered a pest that killed trees and devalued natural habitats, but studies have shown that it could actually have a positive effect on biodiversity and provide high quality food and habitats for wildlife.