By Jim White, Associate Director, Land and Biodiversity
The Christmas season is upon us and colored lights, inflatable Santas, and other traditional and not so traditional holiday decorations are popping up everywhere. There is one very old traditional decoration that, much to my dismay, has lost favor in recent years. Not only do I miss the activity that is associated with hanging this decoration, I miss the plant itself. Of course the decoration is mistletoe – one of the most unusual and interesting of our native plants.
There are approximately 365 species of Mistletoe worldwide with approximately 10 species or subspecies found in the US. There is only one species found in Delaware, the American Mistletoe, Phoradendron serotinum serotinum. Here it typically is found along the edges of wet woodlands or freshwater swamps. In Delaware it seems to be most common along the Delaware Bay coast but can also be found inland along freshwater streams and swamps as far north in the state as the town of Smyrna.
Mistletoe species are in the unusual plant family Viscaceae. Plants in this family are hemi-parasitic on other plants obtaining their all of their water and essential elements such as nitrogen from the host plant. However mistletoe, like other typical plants, manufactures its food in its leaves by photosynthesis. In our area the American Mistletoe’s favorite host appears to be the Red Maple but it can also be found growing on other species of maples and several other tree species.
The life cycle of the American Mistletoe starts when the white berries are eaten by Cedar Waxwings, American Robins, and other berry-eating birds. The berry then passes through the bird’s digestive tract, removing the outer fruit covering, leaving a very sticky seed. If the bird defecates while perched in a tree, the seed will stick fast to the branch. In fact the name “mistletoe” roughly is an Anglo Saxon word meaning a twig with bird droppings. The seed then sends out embryonic roots that spread laterally, and down into the branch, anchoring the seed. If the branch belongs to an appropriate host tree the seed sends down a root-like structure called the haustorium into the branch. The haustorium is used to extract all the water and minerals from the tree that the mistletoe needs to survive. Soon the seed sends up a stem that sprouts the green, fleshy leaves. The shrubby plant can grow as large as three feet in diameter. The number of mistletoe plants growing in an individual tree varies greatly from a single plant to so many plants that a majority of the branches are infected.
Mistletoe apparently has played a part in the folklore of many cultures over the years. The Christmas tradition of hanging mistletoe overhead may have its roots in the pre-Christian druid culture in Eastern Europe. The evergreen plant was collected and used in rituals associated with the winter solstice. The origin of the more recent tradition of kissing under the mistletoe is difficult to pinpoint but may be connected to folklore that suggests that the plant has power over love. Whatever its origin, it always seemed like a great Christmas tradition to me. So the next time you are along the Delaware coast look for green patches in otherwise leafless trees. And if you happen to be with your favorite guy or gal in the wilds of Delaware this winter you might want to take advantage of this yule-time tradition.