National Collection of Imperiled Plants

CPC National Collection Plant Profile

Photographer:

c. 1991 Steve Shirah

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CPC National Collection Plant Profile

Dicerandra christmanii

Family:	Lamiaceae
Common Names:	Christman's dicerandra, Garrett's mint
Author:	R.B. Huck & Judd
Growth Habit:	Perennial
CPC Number:	7052

Distribution
Protection
Conservation
References

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Photographer: c. 1991 Steve Shirah

Dicerandra christmanii is Fully Sponsored

Primary custodian for this plant in the CPC National Collection of Endangered Plants is:

Bok Tower Gardens

S.K. Maddox contributed to this Plant Profile.

Dicerandra christmanii

Dicerandra christmanii is a small fragrant shrub smelling of eucalyptus. It reaches a height of up to 1.3 feet tall. The stems are square with low ridges. Both stems and leaves, which are pitted with oil glands, have a strong mint odor. The narrowly oblong leaves are about 1 inch long, have smooth edges, and grow opposite each other. The vegetative and flowering branches are stiff as they rise from the branching woody base. The tap root is also branched with extensive, spreading, fibrous roots.

Blooming in July - November, the flowers of Garrett's mint, or Garrett's scrub balm as it is sometimes called, grow in whorls around the square stem with 1 - 3 flowers per whorl. The white or cream colored flowers have purple spots and lines, are 2-lipped with rounded lobes and have sharply bent tubes. The stamens have bright yellow anthers that extend beyond the flower (FNAI 2000). The pistil is white, as well as the pollen, and the fruit is a schizocarp of four ovoid, brown, smooth nutlets. The seeds do not have mechanisms for wind dispersal and generally fall close to the plant (USFWS 1999).

This species strongly resembles another endangered mint, Dicerandra frutescens. The two can be differentiated by scent, leaf size, and flower color. D. christmanii smells of menthol, has shorter leaves, brilliant yellow anthers, and cream-colored flowers that maintain their color, while D. frutescens smells minty, has deep purple to white anthers, and a cream flower that fades to white. (Huck et al. 1989)

Distribution & Occurrence

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State Range

Florida

Habitat

Dicerandra christmanii is found within openings in oak scrub habitat (Huck et al. 1989). It prefers open areas because it does not grow well when in shaded conditions. The species occurs on well-drained yellow sands of Astatula and Tavares soil types. Another characteristic of its habitat is a seasonal high water table of at least 1 to 2 m deep. (USFWS 1999)

Distribution

Garrett's mint is endemic to Florida, and is only found in Highlands County at this time. Having a extremely small range, all five known populations are located between Lake Jackson and Lake Istokopga (USFWS 1999).

Number Left

There are 5 populations of Garrett's mint in Highlands County, none of which are protected. (USFWS 1999)

Protection

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Global Rank:	G1	2/29/2000	Guide to Global Ranks
Federal Status:	LE	10/24/1996	Guide to Federal Status
Recovery Plan:	Yes	5/18/1999

State/Area Protection

State/Area	Rank	Status	Date

Conservation, Ecology & Research

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Ecological Relationships

� Like other Dicerandra species, Garrett's mint contains essential oils which protect it from feeding animals. Interestingly, the oil found in this species is compositionally different than the oil found in other Dicerandra, which explains it's unique menthol-like smell. (USFWS 1999)
� This species is pollinated by bee-flies, but seldom other insects (USFWS 1999).

Threats

� Loss of habitat due to urbanization and agriculture.
� Suppression of fire which limits open areas.
� Erosion due to off-road vehicular traffic, and dumping of trash.
� Exotic pest plant invasion.
(USFWS 1999)

Current Research Summary

� Archbold Biological Station (ABS) has integrated research into the conservation biology of Dicerandra christmanii with monitoring efforts.
� ABS is investigating the breeding system, pollinators, demographic patterns, and genetic variability.
(USFWS 1999).

Current Management Summary

There has been no research done on the response of D. christmanii to management practices. This species is, however, very similar to D. frutescens, and is likely to respond in a similar manner. Periodic fire appears to benefit D. frutescens. Though growth is vigorous in areas that have burned, it is not evident that the frequency of fire is as important than the fact that the area had burned in the past. Based on the reaction of the scrub mint, Garrett's mint should require a burning or alternative disturbance regime to maintain the quality of its habitat. Efforts should also be made to protect the sites from trash dumping and foot and vehicle traffic that cause erosion. D. christmanii is adversely affected by trampling (USFWS 1999).

Research Management Needs

� Conduct surveys for additional populations.
� Maintain distribution of known populations and suitable habitat in GIS database.
� Protect and enhance existing populations, including ex situ collection.
� Continue research online history characteristics.
� Monitor existing populations of D. christmanii.
(USFWS 1999).

Ex Situ Needs

� Conduct research on seed storage.
� Conduct further research on propagation methods.
� Provide educational materials for the public.
(USFWS 1999).

References

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Books (Single Authors)

Coile, N.C. 2000. Notes on Florida's Regulated Plant Index (Rule 5B-40), Botany Contribution 38. Gainesville, Florida: Florida Dept. of Agriculture and Consumer Services, Division of Plant Industry.

FNAI. 2000. Field Guide to the Rare Plants and Animals of Florida online. Florida Natural Areas Inventory.

Huck, R.B. 1987. Systematics and evolution of Dicerandra (Labiatae) (Phanerogamarum monographiae XIX). Stuttgart, Germany: Gebruder Borntraeger Verlagsbuchhand-lung.

Nelson, G. 1996. The Shrubs and Woody Vines of Florida. Pineapple Press, Incorporated. 464p.

Books (Sections)

Dolan, R.W.; Menges, E.S. 1998. Chapter 9: Genetic Variation in Nolina brittoniana and Dicerandra Species. In: Menges, E.S.; Dolan, R.W.; Gordon, D.R.; Evans, E.K.; Yahr, R., editors. Demography, ecology, and preserve design for endemic plants of the Lake Wales Ridge, Florida: Final report to The Nature Conservancy's ecosystem research program.

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Electronic Sources

(2001). Floridata - Encyclopedia of Plants and Nature. [Searchable Web site] Floridata.com LC. http://www.floridata.com/tracks/scrub/endangered/menu_end.htm. Accessed: 2002.

(2001). Herbarium Type Specimens. [Web site] State University System of Florida Publication of Archival Library & Museum Materials. http://sid.fcla.edu/mrsid/herb/. Accessed: 2002.

(2002). Atlas of Florida Vascular Plants. [Web site] University of South Florida Institute for Systematic Botany. http://www.plantatlas.usf.edu/isb/default.htm. Accessed: 2008.

(2002). New York Botanical Garden--The Virtual Herbarium. [Searchable Web site] New York Botanical Garden. Fordham Road Bronx, New York. http://scisun.nybg.org:8890/searchdb/owa/wwwspecimen.searchform. Accessed: 2002.

Denton, S. (2001). Photo Library of Native and Naturalized Plants of Florida. Biological Research Associates. http://www.biolresearch.com/Plants/index.php?id=C. Accessed: 2002.

USGS. (2002). Status of Listed Species and Recovery Plan Development. [Web site] USGS: Norther Prairie Wildlife Research Center. http://www.npwrc.usgs.gov/resource/distr/others/recoprog/plant.htm. Accessed: 2002.

Journal Articles

1988. Botanists Discover Two New and Rare Species. Plant Conservation: A Publication of the Center for Plant Conservation. 3, 3

Christman, S. 1989. Yellow scrub balm. Palmetto. 8, 4: 3.

Eisner, T.; McCormick, K.D.; Sakaino, M.; Eisner, M.; Smedley, S.R.; Aneshansley, D.J.; Deyrup, M.; Myers, R.L.; Meinwald, J. 1990. Chemical defense of a rare mint plant. Chemoecology. 1, 1: 30-37.

Huck, R.B.; Judd, W.S.; Whitten, W.M.; Skean, J.D., Jr.; Wunderlin, R.P.; Delaney, K.R. 1989. A new Dicerandra (Labiatae) from the Lake Wales Ridge of Florida, with a cladistic analysis and discussion of endemism. Systematic Botany. 14, 2: 197-213.

Jennings, M. 1997. The Treasures of the Lake Wales Ridge. Endangered Species Bulletin. 22, 2: 14-16.

Judd, W.S.; Huck, R.B. 1989. Abstract 626: A new Dicerandra (Labiatae) from the Lake Wales Ridge of Florida, with a cladistic analysis and discussion of endemism. American Journal of Botany. 76, 6

Kral, R.D. 1982. Some notes on Dicerandra (Lamiaceae). Sida. 9, 3: 238-262.

Martin, T. 2000. Florida's Desert: Saving a vanishing treasure. Plant Talk. 21: 26-29.

McCormick, K.D.; Deyrup, M.A.; Menges, E.S.; Wallace, S.R.; Meinwald, J.; Eisner, T. 1993. Relevance Of Chemistry To Conservation Of Isolated Populations: The Case Of Volatile Leaf Components Of Dicerandra Mints. Proceedings of the National Academy of Sciences of the United States of America. 90, 16: 7701-7705.

McDonald, D.B.; Hamrick, J.L. 1996. Genetic variation in some plants of Florida scrub. American Journal of Botany. 83, 1: 21-27.

Menges, E.S. 1992. Habitat preferences and response to disturbance for Dicerandra frutescens, a Lake Wales Ridge, Florida, endemic plant. Bulletin of the Torrey Botanical Club. 119, 3: 303-313.

Menges, E.S.; Dolan, R.W.; Yahr, R.; Gordon, D.R. 2001. Comparative genetics of seven plants endemic to Florida�s Lake Wales Ridge. Castanea. 66: 98-114.

Menges, E.S.; McIntyre, P.J.; Finer, M.S.; Goss, E.; Yahr, R. 1999. Microhabitat of the narrow Florida scrub endemic Dicerandra christmanii, with comparisons to its congener D. frutescens. Journal of the Torrey Botanical Society. 126, 1: 24-31.

Shinners, L.H. 1962. Synopsis of Dicerandra (Labiatae). Sida. 1, 2: 89-91.

USFWS. 1984. Four Plants in Danger. Endangered Species Technical Bulletin. 9, 8: 1, 5-7.

USFWS. 1984. Regional Briefs. Endangered Species Technical Bulletin. 9, 7: 2, 6.

USFWS. 1985. Dicerandra christmanii (Garrett's mint) -- Distribution: U.S.A. (FL). Listing information. Federal Register. 50: 45618.

USFWS. 1989. Dicerandra christmanii (Garrett's mint) determined to be endangered. Federal Register. 54, 182: 38946-38947.

USFWS. 2001. A newsletter dedicated to sharing information about the Florida scrub ecosystem. U.S. Fish & Wildlife Service: Saving Our Scrub. 2, 3: 8.

Wallace, S.R. 1991. Central Florida Scrub: Trying to Save the Pieces. Endangered Species UPDATE. 8, 1: 60-62.

Newspaper Articles

Hinnant, Lee. 1988 Sunday, March 27. Researcher discovers new plant. Tampa Tribune; Tampa, FL.

Reports

Menges, E.S. 1995. Report on Experimental Research and Monitoring of Four Species of Endangered Plants on the Lake Wales Ridge, Florida. Tallahassee, Florida: Florida Division of Forestry: Statewide Endangered and Threatened Plant Conservation Program.

Menges, E.S.; Weekley, Carl W. 1999. Final Report on Continued Ecological Monitoring and Experimental Research on Four Florida Scrub Endemic Plants. Tallahassee, Florida: Florida Division of Forestry: Statewide Endangered and Threatened Plant Conservation Program.

Menges, E.S.; Yahr, R. 1996. Continued Ecological Monitoring and Research on Four Florida Scrub Plants. Tallahassee, Florida: Florida Division of Forestry: Statewide Endangered and Threatened Plant Conservation Program.

Menges, E.S.; Yahr, R. 1998. Final Report on Continued Ecological Monitoring and Experimental Research on Four Florida Scrub Endemic Plants. Tallahassee, Florida: Florida Division of Forestry: Statewide Endangered and Threatened Plant Conservation Program.

USFWS. 1999. South Florida Multi-species Recovery Plan. Atlanta, GA: U.S. Fish and Wildlife Service, Southeast Region.

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This profile was updated on 3/4/2010