Lakela's Mint

Dicerandra immaculata

Description

Lakela's mint, Dicerandra immaculata, is a low-growing, dome-shaped shrub with a woody base and non-woody stems, reaching a height of 15 in (38 cm) and bearing opposite, oblong leaves. Flowers in small flat-topped clusters are borne at the ends of the stems. The lavender to purple flowers distinguish Lakela's mint from other mint species. Blooming is mainly from September to November, but occurs sporadically through the rest of the year.

Habitat

This mint is restricted to coastal sand-pine scrub vegetation on dunes of highly drained, extremely acidic sterile soils of the Astatula, Paola, and St. Lucie sands. Sand pine is the dominant tree, with an understory of various oaks. Associated trees and shrubs include scrub hickory, cabbage palm, saw palmetto, hog plum, and tough bumelia. The habitat is 45 ft (14 m) above sea level. Lakela's mint requires nearly full sun and does not tolerate much competition from other plants.

Distribution

Historically, Lakela's mint probably grew along much of the Florida peninsula. Today only nine sites remain. The species was first described in 1963 from specimens collected from southern Indian River County.

The number of remaining plants is so small that the Lakela's mint gene pool has been dangerously depleted. A population along Route 1 was destroyed in 1982 during construction of a parking lot. This population was noted for several white-flowered plants that grew three times the average size. Since the loss of this site, white-flowered plants have been found only once.

The nine remaining Lakela's mint sites are clustered in an area of about 1.5 sq mi (5 sq km) in Indian River and St. Lucie Counties, between the cities of Vero Beach and Fort Pierce. There are no current population estimates, but numbers are considered critically low.

Threats

Shortly before this species was listed in 1985, one population was destroyed by a commercial development, and two sites were partially cleared for housing, destroying most of the plants. Two other sites are currently threatened by active sand mining.

Peninsular Florida has one of the highest growth rates in the United States, and consequently development will continue to encroach onto the Lakela's mint habitat. The mint is also vulnerable to mildew attack, which destroys the viability of the seeds before they can be dispersed.

Conservation and Recovery

Protection for this species requires the cooperation of the private owners of the remaining nine sites. One site has already been fenced, and the U. S. Fish and Wildlife Service hopes to negotiate conservation agreements with other landowners. Long-term recovery of Lakela's mint may well depend on nursery propagation. The plant has been successfully grown from cuttings by a commercial nursery in South Carolina. Three plants were recently grown from seed at the National Herb Garden, Washington, D.C. The goal is to develop nursery stocks of the plant to enable eventual reintroduction to areas of suitable habitat.

Contact

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

References

Kral, R. 1983. A Report on Some Rare, Threatened, or Endangered Forest-Related Vascular Plants of the South. Vol. 2, Aquifoliaceae through Asteraceae. U.S.D.A. Forest Service Publication, Washington, D.C.

Robinson, A. F., Jr. 1981. "Dicerandra immaculata." Status Review Prepared for U.S. Fish and Wildlife Service, Jacksonville.

U.S. Fish and Wildlife Service. 1985. "Determination of Endangered Status for Dicerandra immaculata (Lakela's mint)." Federal Register 50: 20212-20215.

U. S. Fish and Wildlife Service. 1987. "Recovery Plan for Three Florida Mints." U.S. Fish and Wildlife Service, Atlanta.