Smooth Coneflower

Echinacea laevigata

Description

The smooth coneflower (Echinacea laevigata ) is a rhizomatous perennial herb. This plant grows up to 5 ft (1.5 m) tall. The stems are glabrous and possess only a few leaves (up to 8 in [20 cm] long, 3 in [7.5 cm] wide). The smooth to slightly rough basal leaves are elliptical to lanceolate with long stems. The mid-stem leaves have shorter stems and are smaller in size than the basal leaves. The rays of the flowers are light pink to purplish and the flower heads are usually solitary. Flowering occurs May through July. The fruit is a gray-brown, oblong-prismatic achene, 0.2 in (0.4-0.5 cm) long. The seeds are 0.2 in (0.5 cm) long.

Seeds are probably dispersed by seed-eating birds or small mammals. Although data are unavailable regarding smooth coneflower, gold-finches, as well as white-tailed deer, have been observed feeding on the seed heads of the endangered Tennessee coneflower. Seeds of the Tennessee coneflower are seldom dispersed by wind more than 3 ft (0.9 m) beyond the parent.

Habitat

The smooth coneflower inhabits open woods, cedar barrens, roadsides, clearcuts, dry limestone bluffs, and power line rights-of-way. In Virginia the soils are magnesium and calcium rich associated with limestone. In North Carolina the magnesium and calcium rich soils are associated with gabbor; diabase in North and South Carolina; and marble in South Carolina and Georgia. Smooth coneflower appears to need bare soil that is rich in magnesium and/or calcium for seedling germination and growth.

The smooth coneflower favors sites characterized by an abundant amount of sunlight with little or no competition in the herbaceous layer. Natural fires and large herbivores are part of this species' habitat. Many associated herbs are cormophytic, sun-loving species that depend on periodic disturbances. These disturbances reduce shade and threats of competition by woody plants.

In Virginia, smooth coneflower sites are sometimes shared with tall larkspur (Delphinium exaltatum) and Addison's leather flower (Clematis addisonii ), both of which are candidates for federal listing.

Distribution

Historically, the smooth coneflower was distributed in Pennsylvania, Maryland, Virginia, North Carolina, South Carolina, Georgia, Alabama, and Arkansas. This species is known extant only in Virginia, North Carolina, South Carolina, and Georgia. Sixty-four percent of this species' populations have been extirpated since 1888.

The smooth coneflower is currently located in Pulaski, Montgomery, Campbell, and Franklin Counties, Virginia; Durham and Granville Counties, North Carolina; Oconee and Anderson Counties, South Carolina; and Stephens County, Georgia. Additionally this species occurs on lands managed by the U.S. Forest Service, U.S. Army Corps of Engineers, South Carolina Department of Highways and Public Transportation, Clemson University, North Carolina Department of Agriculture, the Nature Conservancy (private), and the South Carolina Heritage Trust Program (private). Of the 21 remaining populations, 13 are considered declining in numbers of plants, seven are stable, and one is increasing.

Threats

The smooth coneflower is endangered by collecting, encroachment of woody vegetation, residential and industrial development, and certain types of roadside and power line right-of-way maintenance.

The smooth coneflower is and has been threatened by alteration of its habitat. Silvicultural and agricultural practices, and industrial and residential development, have partially contributed to the alteration of habitat.

Highway construction, construction of a gas line, and conversion of a site to pine plantation have been known factors in extirpation of at least one population. Many populations are on the edges of highway utility rights-of-way. Many common native coneflowers are in demand for horticultural use and are a significant part of the commercial trade. Publicity may generate an increased demand for this species.

Many species of the genus Echinacea have been harvested for pharmaceutical trade.

This species relies on some type of periodic disturbance to clear encroachment of woody vegetation and reduce shading. Fire, well-timed mowing or careful clearing is essential to maintaining the glade remnants occupied by this plant.

Conservation and Recovery

In Virginia, one coneflower population site is owned by the Nature Conservancy, and negotiations are underway with the landowners of at least two other sites for protection. The site owned by the Nature Conservancy was mowed in 1987 to manage for the coneflower and other rare associates; the mowing was followed by an initial depression in numbers of flowering plants, followed by an almost 100% increase in numbers of stems four years later.

The Virginia Department of Conservation and Recreation and the Nature Conservancy have initiated a landowner contact program for priority coneflower sites in Montgomery County, which is a stronghold for the species. Voluntary protection agreements have been secured with several key landowners, and negotiations for stronger protection continue.

In North Carolina, one of the largest known populations of the species is located on land owned by the North Carolina Department of Agriculture. This site, known as the Picture Creek Barrens, was formerly proposed as a site for a hazardous waste incinerator; however, the site is not currently under active consideration for that project. In the spring of 1994, the North Carolina Department of Agriculture's Plant Conservation Program, with funding from the U.S. Forest Service (USFS), initiated a prescribed-burning management program for this smooth coneflower site, resulting in a favorable response by the coneflowers. At another site near Falls Lake, the U.S. Army Corps of Engineers evaluated a series of management alternatives and selected mechanical removal of woody species every four years as a more logistically feasible alternative than fire. Regular monitoring is being conducted so that the management regime may be adjusted as necessary to more effectively benefit the species. In 1993, part of the coneflower population on the Falls Lake site was damaged by a logging operation. The Army Corps of Engineers intervened to reduce the damage and took measures to prevent any future occurrences of this type. The North Carolina Department of Transportation has marked roadways to protect roadside populations of this species from accidental destruction or mowing at the wrong time of year (safe mowing dates are November to early March).

Most of the surviving populations of smooth coneflower in South Carolina occur on the Sumter National Forest, where the USFS began the first experimental management for this species using fire. The first prescribed burn was conducted in the late winter of 1992, following clearing of the woody vegetation from the site in the fall of 1991. The number of flowering stems of smooth coneflower on the site quadrupled in the year following the burn. In an adjacent stand, which was burned without prior canopy removal, the response was a tenfold increase in the number of coneflower rosettes. These plants have little side competition and are suppressed only by the shade from overstory trees. On the Savannah River site, the Department of Energy and the USFS are working with experimental canopy thinning and prescribed fire. A small population (five individuals) was discovered at Fort Jackson, where the Department of the Army is now protecting the site and is developing a management plan.

In Georgia, most of the smooth coneflower populations are located on the Chattahoochee National Forest, where the USFS is monitoring them and protecting the plants from mowing during the wrong season. Plans are underway to reestablish the species at a site there, using plants propagated from seeds from the reestablishment site.

The North Carolina Botanical Garden has acquired seeds and/or plants from several of the North Carolina populations of smooth coneflower. Part of this material is maintained as living plants. Seeds are also being maintained in long-term storage at the U.S. Department of Agriculture's National Seed Storage Laboratory in Ft. Collins, Colorado. If, as seems likely, currently extant wild populations of smooth coneflower are extirpated in the future, propagules gathered and stored could be used to reintroduce the species to sites where it has been extirpated. Although such a method of conservation of the species is not ideal, it serves as a prudent backup for this highly vulnerable species.

Contacts

U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345-3319
http://southeast.fws.gov/

U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
300 Westgate Center Dr.
Hadley, Massachusetts 01035-9589
Telephone: (413) 253-8200
Fax: (413) 253-8308
http://www.northeast.fws.gov/

References

U.S. Fish and Wildlife Service. 8 October 1992. "Endangered and Threatened Wildlife and Plants; Echinacea laevigata (Smooth Coneflower) Determined to Be Endangered." Federal Register 57 (196): 46340-46344.

U.S. Fish and Wildlife Service. 18 April 1995. "Smooth Coneflower Recovery Plan." U.S. Fish and Wildlife Service, Atlanta, 42 pp.