26 March 2010

Spotlight On...Dwarf Mistletoe

Dwarf Mistletoe
Arceuthobium spp.

Viscaceae (Mistletoe Family)

What's in a Name?
Viscaceae has the same root as "viscus," and refers to mistletoe's sticky berries, which were historically used to make birdlime. Handfuls of ripe berries were chewed or boiled, formed into long strands and coiled around tree branches. A bird lands on the sticky branch and there he stays, until the bird-eating hunter returns to pluck him off. This is illegal in many countries now, by the way. Birdlime was also used to manufacture British sticky bombs in WWII.

According to some accounts, "mistletoe," originally mistelta in Saxon, comes from three Sanskrit words: Mas (the Messiah), tal (the womb), and tu (motion to or from). This is the first clue to the enormous cultural power Mistletoe has held throughout history. Read on.

Quick ID:  
In Montana, you'll find Dwarf Mistletoe, which looks a bit like coral, clinging to branches of Ponderosa, Lodgepole and Limber Pine, Douglas Fir and Western Larch. It's a hemiparasite, relying on its host conifer for most of its water and nutrients. There are 42 species of Arceuthobium worldwide (21 endemic to the US) that prey on members of the Pinaceae and Cupressaceae families. All have greatly reduced leaves (just scales, really) with the bulk of the plant living inside the host. Here's how it works:

Remember those sticky berries? Well, they're not just built to help ancient bird-eaters trap their dinner, oh no. As the berries ripen, they swell with hydrostatic pressure, which builds and builds until POW! The fruits burst open, sending seeds flying through the air at 50 mph. If they're lucky, these sticky little seeds land on a suitable host plant and get to work. Their root-like "haustoria" grow into the xylem (water pipes) and phloem (food pipes) of the host, thus beginning its slow decline and eventual death.
Sometimes the best way to spot Dwarf Mistletoe is to look for the peculiar "witch's broom" growths it creates on trees. These dense masses of branches could be mistaken for bird's nests, but they're actually just a bunch of branches growing out from a single point, and can be caused by fungi, insects, mites, nematodes, viruses, frost, forest thinning . . . and, of course, mistletoe.

Folklore and Fables Dwarf Mistletoe is cousin to the American Mistletoe (Phoradendron flavescens), the leafy plant we all know from the holidays. The mythology of mistletoe goes back thousands of years, far beyond that quick kiss at Christmas.  Perhaps it's because mistletoe's evergreen leaves seem a symbol of everlasting life (ironic, since it's also known as the "Vampire Plant" that sucks the life out of its host).

Throughout history and worldwide, it is considered a bestower of fortune, aphrodesiac, antidote to poison and curer of ills. In the Christian faith, mistletoe (mistelta) represented the time between the conception and birth of Jesus, and was supposedly "applied" to him as an infant. Mistletoe was considered sacred long before that, however.
Roman scholar Pliny the Elder (23-79 CE) wrote of the Druids' relationship with the plant, which they held to be the most sacred of all living things save oaks (the Gaelic word druidh means "oak-knower"). European Mistletoe figured prominently in Greek mythology, and Romanians still use the plant for its magical and medicinal properties. The use of mistletoe at Christmas dates back to the 18th century, but kissing under the mistletoe comes from a Norse myth. The story, basically, is this:

Baldr, god of vegetation, was killed by a spear made of mistletoe. His death brought winter to the world (no good!) so the gods restored him. His mom Frigga declared mistletoe sacred, a bringer of love rather than death. To celebrate Baldr's happy return, any two people passing under the plant now must make the obligatory smooch.

In Scandinavia, it's still considered a plant of peace, under which enemies can declare a truce or quarreling lovers make up.

Medicine The plant has been purported to cure cancer and epilepsy, among other things. Suzanne Sommers made headlines when she opted for a mistletoe extract (Iscador) in lieu of chemotherapy following her treatment for breast cancer. There are several accounts, however, of mistletoe's poisonous properties that should not be taken lightly!

Ecology Many Dwarf Mistletoe species are considered to be serious threats to forest health. Severe infection can lead to reduced growth, seed and cone development, poor wood quality, increased susceptibility to disease and insect attacks, and premature death. Most of western North America's commercially important conifers are hosts to at least one Dwarf Mistletoe species.  Interestingly, higher rates of mistletoe infestation have been linked with higher numbers and greater diversity of birds and other animals, perhaps by creating more nesting sites within the tell-tale witch's broom.

Spotlight On... features Montana native plants that are currently on display in our natural areas. Have a plant that you'd like to see featured? Let us know!

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