''Dicerandra christmanii'' is a rare species of flowering plant in the mint family known by the common names Garrett's mint, yellow scrub balm, and Lake Wales balm. It is endemic to Highlands County, Florida, in the United States, where it is known from only four sites on the Lake Wales Ridge.USFWS
''Dicerandra christmanii'' Five-year Review.
September 2009. All are contained within a tract of land measuring 6 kilometers by 3 kilometers. The plant is steadily declining due to the destruction and degradation of its habitat, and only one of the four occurrences is on protected land. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

. The plant was first collected in 1948 by Ray Garrett. Over the years it was included within the description of its close relative, '' Dicerandra frutescens''. In 1989 it was reexamined and named as a new species on the basis of the color of its

anthers The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

, its scent and certain related chemical compounds in the herbage, and the length of its leaves.Huck, R. B., et al. (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. ''D. christmanii'' has white or cream-colored flowers with yellow anthers, a

menthol Menthol is an organic compound, more specifically a monoterpenoid, made synthetically or obtained from the oils of corn mint, peppermint, or other mints. It is a waxy, clear or white crystalline substance, which is solid at room temperature and ...

scent, and shorter leaves, while ''D. frutescens'' has cream flowers that fade to white, and purple or white anthers.''Dicerandra christmanii''.
Center for Plant Conservation. The two are otherwise quite similar in appearance. ''D. christmanii'' is an aromatic

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

growing up to 1.3 feet tall. The squared, ridged stem and oppositely arranged leaves have many oil glands. Blooming occurs in summer and fall. Flowers occur singly or in whorls of three. Each is white to cream in color with purple spotting on the lobed lips. The yellow-anthered stamens protrude from the mouth of the corolla and bear white

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

. The anthers have spurs that trigger the release of pollen, a trait common to genus ''Dicerandra''. The plant is pollinated most often by '' Exprosopa fasciata'', a species of

bee-fly The Bombyliidae are a family of flies, commonly known as bee flies. Adults generally feed on nectar and pollen, some being important pollinators. Larvae are mostly parasitoids of other insects. Overview The Bombyliidae are a large family of ...

. This plant is one of many that is found only on Lake Wales Ridge, an area of very high endemism. The habitat is yellow-sand Florida scrub dominated by sand pines (''Pinus clausa''), several species of oak, and scrub hickory (''Carya floridana''). It does not occur together with ''D. frutescens'', but slightly to the north of its relative. The habitat is highly fragmented, with land in the area converted to citrus groves. Remaining parts are degraded, the wildfire-adapted habitat having been overgrown with dense vegetation in an era of

fire suppression Wildfire suppression is a range of firefighting tactics used to suppress wildfires. Firefighting efforts in wild land areas require different techniques, equipment, and training from the more familiar structure fire fighting found in populated a ...

. The mint only grows in open areas in the canopy, space which is rare today as the larger and woody vegetation succeeds. Fire is also required to clear out leaf litter in the understory. Furthermore, plants of this species in open habitat are more likely to be visited by

pollinator A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are the maj ...

s than plants under overgrown canopy. Besides outright habitat loss and lack of a natural fire regime, threats to the species include drought and the

invasive weed An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

cogon grass (''Imperata cylindrica''). The plant has a limited ability to disperse its seeds, and this is reduced more by the fragmentation of the habitat. Off-road vehicles and trash dumping may affect the area. Because ''D. frutescens'' was already on the endangered species list, ''D. christmanii'' was given that status when it was separated and named a new species.USFWS
''Dicerandra christmanii'' (Garrett's mint) determined to be endangered.
''Federal Register'' September 21, 1989. It is considered "one of the most critically endangered plant species on the Lake Wales Ridge," among many endangered species.Haller, S. J. and E. S. Menges
Demographic results emphasize need for habitat manipulation and augmentation in a rare scrub plant (abstract).
95th ESA Annual Meeting, Pittsburgh, August 2010.

References

External links

USDA Plants Profile
{{Taxonbar, from=Q5272383 christmanii Endemic flora of Florida Plants described in 1989 Highlands County, Florida