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Large-flowered rosemary, Conradina grandiflora growing in a pine upland. Photo courtesy of K. Hill, Smithsonian Marine Station.


Close-up of Conradina grandiflora. Photo courtesy of K. Hill, Smithsonian Marine Station.

Species Name: Conradina grandiflora Small
Common Name: Large-flowered rosemary
Largeflower false rosemary
Scrub mint
Synonymy: None
  1. TAXONOMY

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Plantae Magnoliophyta Magnoliopsida Lamiales Lamiaceae Conradina

    Other Taxonomic Groupings

    Subkingdom : Tracheobionta
    Subclass : Asteridae

    Species Description

    A member of the mint family, Conradina grandiflora is a perennial, evergreen shrub endemic to Florida. It grows to 1 - 1.5 m (3.3 - 5.0 feet) in height and has grayish bark along the woody portions of the stems. Branches are typically arching or spreading in habit. The aromatic leaves are needle-like and opposite, measuring 1 - 1.5 cm (0.4 - .6 inches) in length. Upper parts of the leaves are dark green, shiny, and marked with small black dots. The lower leaf surfaces may appear white or gray in color due to a dense growth of fine hairs along the stem and leaves (Nelson 1996).

    Blooming occurs throughout the year. Stalked flowers appear on cymes in groups of 1 - 12. Flowers are two-lipped and large, measuring approximately 2 cm (0.8 inches) at the upper lip (Nelson 1996). There are 4 stamens that arch to the upper lip of the flower. Anthers lack horns (Wunderlin 1982; Small 1993), and the calyx is somewhat bent. Flower color is bright blue to lavender, with the lower lip flecked with tiny dark spots. Fruits are small and nut-like, with a smooth skin and dark blue-black color (Nelson 1996).

    Potentially Misidentified Species

    There are 5 species of Conradina that grow in the Southeastern U.S. Conradina grandiflora is distinguished by its large flowers that are bourne on obvious stalks.

  2. HABITAT AND DISTRIBUTION

    Regional Occurrence

    Conradina grandiflora is endemic to the Atlantic Coastal Ridge in eastern Florida. Its range extends from approximately Volusia County to Broward County (Nelson 1996). It has likely been extirpated from Dade County (Kral 1983).

    IRL Distribution

    Conradina grandiflora occurs in all IRL counties in coastal scrub areas, pine scrub, dunes, or sand hills where soil is deep and consists of fine sand (Kral 1983; Nelson 1996).

  3. LIFE HISTORY AND POPULATION BIOLOGY

    Age, Size, Lifespan

    Large-flower rosemary reaches a height of approximately 1 - 1.5m (3.3 - 5.0 feet) and has leaves that measure approximately 1 - 1.5 cm (0.4 - .6 inches) in length (Nelson 1996).

    Abundance

    Conradina grandiflora is considered rare throughout its range; however, it is known to be common in some areas where its coastal scrub habitat has not been disturbed.

  4. PHYSICAL TOLERANCES

    No information is available at this time

  5. COMMUNITY ECOLOGY

    Associated Species

    Conradina grandiflora is associated with plants typical of coastal scrub or pine scrub, including pines (Pinus spp.), Lyonia, hollies (Ilex Spp.), rosemary (Ceratiola sp.), cacti (Opunita spp.), and oaks (Quercus spp.) (Center for Plant Conservation, 2006).

    Habitats

    Large-flowered rosemary generally inhabits coastal backdunes, coastal scrub, maritime hammock, sand pine scrub, and sandhill areas from Volusia through Broward Counties.

  6. ADDITIONAL INFORMATION

    Conradina grandiflora has no Federal status as an imperiled species, though it is listed as Threatened in Florida, having been downlisted from its previous status as Endangered.

    It has has been assigned a global rank of G3 (FNAI 2006), which classifies it as rare and local, or restricted, throughout its range, with 21-100 known occurrences. It is considered vulnerable to extinction due to habitat alteration or loss, with the primary threat being continued development of coastal scrub areas for commercial or residential uses.

    There are no active management plans for specific preservation of Conradina grandiflora, and Florida State Law considers endangered and threatened plants growing on privately owned lands as the property of the owner. However, there are many incentives granted to Florida landowners, both large and small, who wish to conserve the rare and endangered plants and wildlife that occur on their lands.

  7. REFERENCES

    Center for Plant Conservation. 2006. Plant profile: Conradina grandiflora. Accessed online at www.centerforplantconservation.org. June 26, 2006.

    Crook, R.W. 1996. Conradina: Interspecific and Intergeneric Relationships. Tallahassee, FL. Florida Division of Forestry, Statewide Endangered and Threatened plant Conservation program.

    FNAI. 2006. Florida Natural Areas Inventory website. Tracking list for Brevard County. Accessed online at www.fnai.org. June 26, 2006.

    Kral, R. 1983. A report on some rare, threatened, or endangered forest-related vascular plants of the South. Athens, GA, U.S. Dept. of Agriculture Forest Service. U.S. Dept. of Agriculture Forest Service Technical Publication R8-TP2, Vol. 1.

    Nelson, G. 1996. The Shrubs and Woody Vines of Florida. Pineapple Press, Inc. Sarasota, FL.

    Small, J.K. 1993. Manual of the Southeastern Flora. The University of North Carolina Press, Chapel Hill, NC.

    Taylor, W.T. 1992. The Guide to Florida Wildflowers. Taylor Publishing Co., Austin, TX. 320 pp.

    Wunderlin, R.P. 1982. Guide to the Vascular Plants of Central Florida. University Presses of Florida, University of Florida, Gainesville. 175 pp.

Report by: K. Hill, Smithsonian Marine Station
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Page last updated: June 26, 2006

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