Christmas is a time when, to paraphrase Tennyson, a young man's fancy lightly turns to thoughts of mistletoe.
The kissing tradition associated with mistletoe goes back to the Roman festival of Saturnalia and probably beyond. Even the Druids regarded mistletoe as a symbol of power because it occasionally grew on oaks, and of fertility, because it remained green in winter when the host tree had lost its leaves.
Mistletoe twigs were hung at doorways to ward off witches and evil spirits. The word is probably derived from the German 'mist' meaning dung and 'tang' meaning branch, a reference to the way in which seeds are dispersed by birds.
The name mistletoe was originally given to the European species, Viscum album, but is now applied to a large assortment of more or less shrubby, parasitic flowering plants belonging to two families: the Loranthaceae, with about 1,200 species, mainly in Australia, Africa and Asia, and the Viscaceae with some 350 species worldwide.
In North America, mistletoes are represented by the genus Phoradendron (P. flavescens is the floral emblem of the state of Oklahoma), like Viscum with red or white berries and parasitic mainly on broad-leaved trees, and Arceuthobium, the dwarf mistletoes, that grow on conifers causing witches' brooms. Mistletoes are hemiparasites in that they rely on a woody host plant for all of their water and mineral nutrients but are capable of producing at least some of their organic nutrients by photosynthesis. Epiparasitism, in which up to three mistletoes may grow sequentially on one another, is not uncommon.
Many mistletoes are dioecious, meaning that the male and female flowers are borne on separate plants. The flowers of Loranthaceous mistletoes are adapted to pollination by various groups of birds; sunbirds, honey eaters or mistletoe birds. These flowers are robust, waxy and brightly coloured with long floral tubes and copious nectar. The birds either slit the flowers open and are dusted with explosively discharged pollen, or tap on swollen flower buds which open to expose the nectar and pollen.
Birds are also involved in the dispersal of seeds. After the fruits are eaten and digested, the seeds pass through the bird's gut and are released in strings on to the twigs of host plant. A covering of sticky viscin keeps them firmly stuck to the twigs where they germinate and penetrate into the host tissues.
Despite the accepted view that the European mistletoe is poisonous, many peoples have used it, and other species, for medicinal purposes to treat a wide variety of illnesses. Most recently there has been great interest in the anti-cancer properties of mistletoes, attributed to various alkaloids and lectins. Some success has also been claimed for mistletoe extracts in treating AIDS but the effectiveness of these treatments has not been verified in valid tests.
Fresh mistletoe is not readily available in our area. Phone calls brought responses from local florists revealing that mistletoe is rather expensive, not a big seller, and is quite difficult to successfully ship fresh. However, some Safeway stores were scheduled to receive shipments.
Alternatives might be to examine the 'kissing balls' that Safeway is bringing in, take a trip to the forests in Manitoba where the dwarf mistletoes grow, or cultivate friendships with our American neighbours for future Christmas seasons.
However you manage the mistletoe tradition this year, we wish you and yours a wonderful holiday season and the very best for the New Year.
David Punter is a Senior Scholar with the Department of Biological Sciences, University of Manitoba. His research included wild rice and parasitic plants. Jeannie Gilbert is a research scientist with Agriculture and Agri-Food Canada. The topic of her PhD. thesis was the dwarf mistletoe that parasitizes jack pine.
