Apalachicola Rosemary

Conradina glabra

Description

The Apalachicola rosemary is a many-branched shrub that grows to a height of 6.6 ft (2 m). The shrubs often occur in clumped patterns but rhizomatal reproduction has not been confirmed. The branches of this species are spreading or upright. The leaves are evergreen, opposite, with additional leaves in short shoots in the axils giving the appearance of fascicles (small bundles). The leaves are needle-like and hairless on the upper surface. The flowers are generally in groups of two or three. The corolla is 0.6-0.8 in (1.5-2.0 cm) long, from its base to the tip of its longest lobe, with a slender corolla tube that is straight for about 0.2 in (5 mm) long, then bends sharply downward to form a funnel-shaped throat 0.2 in (5 m) long, then widens out into upper and lower lips. The outside of the tube and throat are white, with the lobes and lips lavender blue at the tips. The lower lip of the corolla is three-lobed, with a band of purple dots extending along its inner side. The four stamens are paired. Many flowers are male sterile. In extreme cases, the stamens are malformed and petaloid in shape, texture and color. Male sterility may be the result of inbreeding and homozygosity.

Habitat

Apalachicola rosemary is located in an area of gently undulating upland habitat originally dominated by longleaf pine-wiregrass vegetation. The area is dissected by ravines of the Sweetwater Creek system, which drains westward to the Apalachicola River. Parts of the Apalachicola ravines are incorporated in public and private nature preserves that protect rich hardwood forests with the narrowly endemic Florida torreya and Florida yew. Heads of ravines, called steepheads, have slopes that are undermined by groundwater seeping into the ravine bottom causing the slopes to gradually slump, carrying the vegetation with it. The edges of ravines support mature shrubs which are sometimes carried into the ravines during slumping. Younger Apalachicola rosemary shrubs are found in the barren, exposed soil adjacent to the pines and often extend into the pine stand. This suggests that the species is able to compete effectively in open, newly exposed areas but is unable to compete in closed stands of mixed hardwoods or pines. This species is probably a component of the secondary successional plant community in the area; fires in the area are frequent.

Apalachicola rosemary is also found along roadsides, in planted pine plantations, and along the cleared edges of pine plantations.

Distribution

This species is only found in Liberty County, Florida, west of Tallahassee near the Apalachicola River. There are four natural colonies on lands owned by a forest products company and on public road rights-of-way. Another artificial colony is being created a short distance from the plant's natural range, on similar ravine edges, in the Apalachicola Bluffs and Ravines Preserve, owned by The Nature Conservancy.

Threats

This species appears to require full sunlight or partial shade. Planted pine trees are likely, by the time they mature, to produce dense shade that could kill this species. Another possible problem in planted pines is that sand pine does not tolerate prescribed fire, which may help keep the habitat open for Apalachicola rosemary. Forestry practices may kill the species directly when areas are cut and site-prepared. These plants survived on areas where chopping had not occurred, and did not survive in areas where chopping did occur.

The herbicide hexazinone is sometimes used in timber regeneration areas and its use could affect Apalachicola rosemary.

The very limited distribution of this species and management of most of that range by a single landowner exacerbates the threat to this plant from forestry practices, because the same management practices are likely to be applied rangewide, at the same time.

Some areas formerly occupied by this species have been converted to improved pasturelands, destroying the plants in the process and leaving the area unsuitable for it.

Conservation and Recovery

Research concerning the propagation and reintroduction of this species is needed to insure the success of attempted transplants and to provide an herbarium population capable of providing stock for future transplants. Further research concerning the plant's life history and ecological requirements is also needed.

Contacts

U.S. Fish and Wildlife Service
Regional Office of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
Telephone: (404) 679-4000
http://southeast.fws.gov/

Cookeville Ecological Services Field Office
446 Neal St.
Cookeville, Tennessee 38501-4027
Telephone: (931) 528-6481
Fax: (931) 528-7075

References

U.S. Fish and Wildlife Service. 12 July 1993 "Endangered and Threatened Wildlife and Plants; Endangered or Threatened Status for Five Florida Plants." Federal Register 58(131):37432-37443.