University of Tennessee
Forest Resources AgResearch and Education Center
Plants R

Southern Adder's Tongue Fern (Ophioglossum vulgatum) and
Rattlesnake Fern (Botrychium virginianum)

Two ferns belonging to the plant family Ophioglossaceae can be found along some of the Arboretum trails at this time of year. This group of ferns is considered to have primitive characteristics and is not closely allied to other living ferns. Plants in this family have two-parted leaves, a basal sterile portion that can be simple or compound and an upper fertile portion bearing sporangia.

Southern Adder's Tongue Fern The Southern Adder's Tongue Fern is an unusual fern with a simple, ovate leaf subtending an erect, fertile stalk which bears the sporangia. This fern is widely distributed in the U.S. (many eastern states, Texas and Oklahoma), but is also found in Mexico and Europe. It is often difficult to find and frequently occurs in disturbed areas such as the edges of fields and forested roadsides.

Rattlesnake Fern The leaves of Rattlesnake Fern consist of a basal three-parted compound leaf subtending a fertile spike bearing sporangia. The fertile portion resembles the rattles of a rattlesnake. This fern is found throughout the U.S. and Canada. where it typically occurs in rich, moist forests.

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Red Maple Blooms (Acer rubrum)

Red Maple Bloom Red Maple Bloom
One of the first deciduous trees to bloom in the spring is Red Maple. As you are driving toward the Arboretum or walking along one of the trails, you can see its reddish blooms beginning to appear in the upper forest canopy. Red maple has male and female flowers that occur on separate branches of the same tree, or a tree may have only male or only female flowers. The reddish bloom comes primarily from the female flowers and the fruits as they mature. The male flowers tend to have a yellowish color. The fruits - called samaras - are similar to those of other maples in having two wings. As spring progresses, you are likely to see abundant flower parts and later numerous samaras on the ground as you walk the Arboretum trails. In the fall, the leaves contribute a brilliant red to the forest canopy.

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Redbud (Cercis canadensis)

Redbud Blossoms One of the most beautiful and conspicuous trees at the Arboretum in April is the Redbud. This tree is most commonly seen at forest edges, in disturbed areas, or in managed landscapes. Redbud is a member of the bean family (Fabaceae), and in a natural setting is an early invader of disturbed areas where it grows quickly but is generally short lived (20-25 years). Distinguishing characteristics of Redbud include its rose-pink, pea-like flowers, its heart-shaped leaves, and its flat, brown, bean-like pods.

Redbud At the Arboretum you will see Redbud along several trails and bordering some open areas. A research planting near the Program Shelter is in full bloom. The larger trees in this area are survivors of a failed research study originally planted in 1995. A new planting of redbuds was made in 2007 next to these older trees; the young trees are just becoming established. The objective of the current study is to evaluate Chinese Redbuds and ones from a northern location in the United States for potential introduction in Eastern Tennessee.

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Resurrection Fern (Pleopeltis polypodioides)

Resurrection Fern on Tree Trunk Among the interesting ferns found at the Arboretum is the Resurrection Fern which can be observed on several Eastern Red Cedar trunks along the Cemetery Ridge Trail. It also occurs on rocky ledges off the trails. The fern is an epiphyte (or air plant) - a plant that uses another plant as a substrate but does not depend on that plant for food, nutrients, and water as does a parasitic plant.

Resurrection Fern

During dry periods, the fern's fronds appear shriveled. The common name is based on the fern's ability to expand quickly (i.e., resurrect) in response to a rainy period, such as the rain we had at the end of August. The fern obtains its water and nutrients directly from rainwater and the wet bark or other substrate on which it grows. Resurrection Fern is widely distributed in Tennessee and the Southeastern U.S.

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Roundlobe Hepatica (Hepatica americana)

Roundlobe Hepatica Roundlobe Hepatica is one of our earliest blooming wildflowers along Arboretum trails. Look for it in early March along the lower portions of the Cemetery Ridge Trail and somewhat later along the Oak-Hickory Trail. The flower emerges from the decomposing forest leaf litter as a bright spot of blue or white. The showy sepals (it has no petals) are subtended by green bracts. Its leaves are intermingled with the brown leaf litter and are often difficult to see. The leaf color varies from faded green to purple - the ones present now developed during the previous season and have allowed the plants to photosynthesize during the winter months. New leaves are formed after blooming.

Two species of Hepatica are found in our area. The 3 lobes of Roundlobe Hepatica are relatively shallow and rounded at the tips, while leaves of Sharplobed Hepatica (Hepatica acutiloba) are more deeply lobed and have acutely pointed tips. The genus name Hepatica is based on the resemblance of the leaf to the liver. Hepatica has been used for a variety of medicinal purposes - in the late 1800s, more than 400,000 pounds of dried leaves were used in one year to make a tonic for liver ailments.

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Rue Anemone (Thalictrum thalictroides)

Rue Anemone Numerous small white flowers are conspicuous along the Oak-Hickory Trail in late March and early April. Rue Anemone, or Wind Flower, belongs to the buttercup family. The basal leaves are divided into nine leaflets, each of which has three rounded lobes. The flowers are white to pinkish with several flowers being borne in an umbel - i.e., a long flower stalk with several branches originating from a common point. These plants can also be seen at a low point along the Cemetery Ridge Trail, in the same general location as the Roundlobe Hepatica seen in late March.

Other wildflowers that appear to be a bit later include Mayapple (palmate leaves have emerged), Fly Poison (dark green clusters of basal leaves are particularly conspicuous along the Oak-Hickory Trail), and Violets. Red Maples start blooming in early March, and the red flowers parts shed along the trails. The Magnolia Orchard is near its peak bloom at this time in spring and the ground is covered with purple, red, pink, and white tepals (showy petals and sepals that are undifferentiated).

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University of Tennessee - Forest Resources AgResearch and Education Center
901 South Illinois Avenue, Oak Ridge, Tennessee 37830 · Telephone: 865-483-3571 · Email: UTforest@utk.edu