Christmas Botany

 

American Mistletoe (Phoradendron leucaprum).
Rowan County, North Carolina. 

The Christmas season has many traditions ranging from music, to food, to music, to decorations.  Often the decorations are plants that may have a symbolic meaning but also brighten up the short days of winter. 

European Holly (Ilex aquifolium).
Rowan County, North Carolina.

Holly is one of these traditional decorations.  The tree was sacred to the Romans and associated with the god Saturn. The holiday Roman Saturnalia was observed at the winter solstice and holly was exchanged for good luck.  Today we are reminded in songs from Burl Ives singing “Holly Jolly Christmas” to “Deck the halls with boughs of holly” that this plant plays a key role in Christmas. 

 

American Holly (Ilex opaca) leaf.
Rowan County, North Carolina.

American Holly fruits.
Rowan County, North Carolina. 

American Holly (Ilex opaca) is a large tree native to the forests eastern United States. Its leaves are green throughout the year and have spines on the margins.  American Holly has male and female flowers on different trees so an American Holly with berries is always a female.  European Holly (Ilex aquifolium) is widely planted in American landscapes, and some have escaped and are established in the wild.  European Holly is looks very similar to American Holly, but European Holly has more abundant fruit and shinier leaves. 

American Mistletoe high in a tree.
Rowan County, North Carolina. 

American Mistletoe leaves.
Rowan County, North Carolina. 

American Mistletoe young fruits. 
Rowan County, North Carolina. 

American Mistletoe fruits.
Rowan County, North Carolina. 

Mistletoe is another plant with a long holiday history.  From ceremonies of ancient Druids to hanging mistletoe in a doorway to steal a kiss, this plant is engrained in our culture.  The Druids used European Mistletoe, Viscum album, but in North America we have American Mistletoe (Phoradendron leucarpum).  Like its European relative, American Mistletoe is hemiparasitic and must grow attached to a host tree.  While the bright, leathery evergreen leaves carry out photosynthesis, its water and mineral nutrients are absorbed from its host.  American Mistletoe is dioecious with separate male and female plants.  Around Christmas, the female plants sport small white berries.  American Mistletoe berries are a favorite food of many birds.  Birds eat the fruits that rapidly pass through the digestive system.  The seeds in the fruit are unharmed by this passage but retain a sticky outer layer that makes them adhere to limbs, but also stick to the cloaca of the bird.  To dislodge the seeds the bird rubs its vent on tree branches to deliver Mistletoe seeds to a new host. 

American Mistletoe growing from the trunk
of a Red Maple (Acer rubrum).
Rowan County, North Carolina. 

The Christmas tree is the central botanical symbol of the season.  The tradition of bringing green trees or  branches into the home during winter is found in many cultures.  Christmas trees as we know them originated in Germany and other parts of Central Europe.  Evergreen trees were decorated and lit starting in the starting in the Middle Ages but our modern Christmas owes much to Queen Victoria of England.  Her husband, Prince Albert was German and brought Christmas trees to royal palaces and to widespread public attention in 19th century England. Americans quickly adopted the tradition.    

Fraser Fir (Abies fraseri) on a Christmas tree lot.
Rowan County, North Carolina. 

In the United States many different evergreens are used as Christmas trees.  Our favorite is Fraser Fir (Abies fraseri) an endemic of the high altitude Southern Appalachian Mountains. It can reach 50 feet in height and grows naturally in the Spruce-Fir forests that top the highest peaks.  Fraser Fir is endangered in its natural habitat with threats coming from climate change and an invasive insect, the Balsam Wooly Adelgid (Adelges piceae). 

Fraser Fir branches.
Rowan County, North Carolina. 

Fraser Fir needles.
Rowan County, North Carolina. 

Fraser Firs grow in a pyramidal shape, have soft needles and strong branches.  These are all excellent characteristics for a Christmas tree.  It is ironic that an endangered species should be a popular Christmas tree, but Fraser Firs are grown by farmers in the Appalachian Mountains down to an altitude of 3000 feet and generate sales of over $100 million per year in North Carolina.  

A fully decorated Fraser Fir.
Rowan County, North Carolina. 

These plants; holly, mistletoe and fir, with their interesting biology and fascinating cultural history add so much to our enjoyment of the season.  So, this Christmas, consider the botany.