by Wendy Diaz, EMGV
During my winter hikes, I have noticed two evergreen perennial plants that are very prominent this time of year because their bright green color contrasts with the brown of the forest floor and the barren top of a leafless tree. These plants, of course, are running-cedar (Diphasiastrum digitatum) and mistletoe (Phoradendron leucarpum) respectively, and are native plants that I became curious about after moving to the Piedmont and so I decided to do a little research.
Running-cedar (Diphasiastrum digitatum) Biology
Running-cedar is part of the Family of Plants known as Club mosses (Lycopdodiaceae). They are ancient plants (evolving over 400 million years ago) that look like mosses and have reproductive parts that resemble clubs, hence the family name. Their flat shiny green branch lets connected by runners look like cedar branches and hence the common name. Other common names are Southern running-pine, ground cedar, fan club moss and bears paw. The aboveground part of the plant that resembles a cedar bough is called the sporophyte and produces tall candle-like structures in July, August or September called strobili. Many spores are released when the strobili ripen and animals disturb the clubs or when the wind blows.
The rarely seen runners, which connect the sporophytes, are usually covered by leaves on the forest floor. The sporophytes form large masses about 6 inches in height. Running-cedar is slow growing and requires good soil moisture or moist, adequate soil moisture retention year-round, which explains why it disappeared from the forest buffer behind my house after the 2007 drought. Its distribution can be found as far north as the Great Lakes and the Maritimes of Canada and as far south as the northern section of South Carolina, Georgia and Alabama in eastern North America. Running-cedar is virtually impossible to transplant.
Interesting Running-Cedar Facts
Because the spores contain a lot of oil, Native Americans used them during their spiritual ceremonies to produce bright light by burning them. Later, early photographers used the spores (Lycopodium Powder) to create a flash of light before taking a picture. The Christmas tradition of using the plant as garlands and wreaths most likely began with the Victorians who would wrap club mosses around their chandeliers and family portraits. At the present time, running-cedar is considered ‘exploitably vulnerable’ in New York State and wildlife flower societies in Virginia and elsewhere discourages the use of running-cedar for decorating.
Mistletoe Phoradendron leucarpum (P. serotinum) is a native evergreen shrub from the Viscaceae Family. Common names, besides mistletoe, are Oak Mistletoe, Christmas Mistletoe and American Mistletoe. This slow growing hemi parasitic plant, which means it is parasitic but to some degree produces its own food through photosynthesis, mainly lives on the branches high in deciduous trees usually in the form of ball-shape clusters. It can grow up to 3 feet in diameter. The most common host trees are oaks and red maples but it also can grow on pecan, hickory, black gum and on about 100 species of trees. Mistletoe’s distribution covers the eastern half of the United States; south of New York State to Florida and west to New Mexico.
Female mistletoe plants produce white berries with sticky pulp or film that birds then eat and spread to other branches or other trees because the film stays sticky as it passes through the bird’s digestive tract. When the seeds are excreted they stick to the branch of the tree and sprout anew. The white berries especially, as well as other parts of the native plant, are poisonous when eaten by humans, pets and livestock. The berries appear in late fall and persist into winter so they are an important food source for many songbirds. Mistletoe attaches to the tree’s upper branches, under the bark, with a root-like structure called the haustorium (haustoria). They absorb water and nutrients from the host tree through their haustorium.
Although a large number of mistletoe plants on a stressed deciduous tree may ultimately contribute to its demise over time, mistletoe’s harmful effects on trees depends on the degree of the infestation. Mistletoe is also beneficial from an ecological perspective because it is important to birds and insects. Birds enjoy the white berries and areas that have large numbers of mistletoe plants in trees are considered to be locations with a ‘healthy and diverse bird population’. It is also the larval host plant for the Great Purple Hairstreak (Atlides halesus) butterfly. Keeping the infested tree resilient by watering, fertilizing and mulching will help but if this is not enough, pruning the infested branch (by a licensed arborist) is recommended. Instructions are outlined in the quoted references. Mistletoe resistant deciduous trees are ‘river birch, crape myrtle or ginkgo’.
Interesting Mistletoe Fact
Norse, Greek and Romans had legends involving mistletoe but the Christmas tradition of a man allowed to steal a kiss from a woman under mistletoe can be traced back to the servants in the 18th Century and gained popularity during the Victorian era among the serving classes.
Whether you are looking up or down, nature in North Carolina always offers something interesting to observe, even in winter!