Smooth Coneflower- Echinacea laevigata
By Rachel Dodgens, Former SCWF Staff
Echinacea laevigata is not the most famous member of its family (or genus for that matter), but it might be the most beautiful. A member of the Asteracea family, E. laevigata’s most well known relative is Echinacea purpurea, known for its medicinal uses.
E. laevigata is commonly called Smooth Coneflower, referring to its smooth, hairless stem. It is a perennial herb, meaning it comes back year after year. The Smooth Coneflower looses all its leaves in the fall, but remains alive underground until the leaves reemerge in March. The plant grows up to 1.5 tall and has very few leaves. The leaves at the base of the plant are the largest and grow to a length of 20cm and a width of 7.5cm. Each leaf is elliptical to broadly lanceolate shaped with toothed edges and tapers at the base, and are alternately placed along the plant.
You will probably notice E. laevigata until May and August when the flower blooms. The flower is a solitary head, similar to a black-eyed Susan. The petals are pink to pale purple, 8cm long, and droopy. The center of the flower is a darker purple. The plant usually flowers once per year, but another flower sometimes appears during the same season.
The fruit of E. laevigata is a gray-brown, 4-angled achene (a small, dry, indehisced one-seeded fruit; like a sunflower seed). Each fruit is approximately 4 to 4.5mm long and contains a seed measuring .5cm. The reproduction of this plant is predominantly sexual; however, asexual, vegetative reproduction has been reported. The Smooth Coneflower needs bare soil for seed germination. Bees and butterflies act as pollinators and birds and small mammals help with seed dispersal.
So why all this discussion of E. laevigata? This beautiful plant has been on the Federally Endangered list since 1992. There are currently 23 remaining populations, seven of which are in South Carolina. Of the 23 remaining populations, 13 are in decline and only one is increasing in numbers. Each of the remaining populations has 100 or less plants.
E. laevigata was historically found in eight states (SC, NC, VA, GA, MD, PA, AL, AR), but currently South Carolina, North Carolina, Georgia, and Virginia are the only states left with populations with South Carolina hosting a large percentage. The species is on the endangered or threatened list in each state. The seven populations here in the Palmetto State are in Oconee and Allendale counties. Two of these are located on the Department of Energy’s Savannah River Site. There are three additional populations in Aiken and Allendale counties, but they are believed to be introduced and not native.
E. laevigata, like all species, ended up on the Endangered Species list for a variety of reasons. The over collection of plants from natural populations is believed to be one of the main reasons. People have collected the plant for its beautiful flower and when trying to collect medicinal E. purpurea. Habitat reduction is also a main source of problems for this species. It prefers open woods, cedar barrens, roadsides, clear cuts, dry limestone bluffs, and powerline right-of-ways. Smooth Coneflower grows best in full sunlight and with periodic disturbance. Natural fires reduce the shade and competition from woody plants. Fire suppression, therefore, is another of E. laevigata’s threats.
Other threats include certain agricultural and silviculture practices, roadway construction and improvement, roadside and powerline right-of-way maintenance, and encroachment of woody vegetation. Encroachment of native and exotic wood species has a negative affect as well. The inadequacy of protection afforded by state laws and enforcement of such laws is sometimes a problem.
Even though E. laevigata is on the Endangered Species list there is still hope. The SC Botanical Gardens has E. laevigata as part of its living collection and also has an Endangered Species Research Unit. Research is being done on the potential for vegetative reproduction, including the optimal time of year to undertake such tasks. It has shown great potential for this kind of production and hormone treatment is not necessary. The Fish and Wildlife Service has a Smooth Flower Recovery plan which includes: research on the biology of the plant, maintaining a cultivated source, and encouraging and assisting nurseries in the development of cultivated stock. Sumter National Forest is working for preservation using prescribed burns. They have also teamed up with the Center for Plant Conservation to plan collection and storage of seeds and plant material. Canopy thinning has also proven to be an effect preservation technique for Smooth Coneflowers because it is not shade tolerant. Periodic disturbance is the primary way for individuals to help; set up a regular fire regime, timed mowing, or careful clearing.