Dicerandra frutescens
Encyclopedia
Dicerandra frutescens is a rare species of flowering plant in the mint family
known by the common names scrub mint and scrub balm. It is endemic to Highlands County, Florida
, where it is known only from the Lake Wales Ridge
. Its habitat is quickly being lost as it is converted to residential and agricultural use. It was federally listed as an endangered species
of the United States in 1985.
This shrub
grows about half a meter tall from a deep taproot
. It is glandular and strongly aromatic with a mint scent. The oblong leaves are roughly 2 centimeters long, smooth-edged, oppositely arranged, and dotted with visible oil glands. The inflorescence
is a pair of flowers each roughly 1.5 centimeters long. The flower has a tubular throat and a lobed, lipped mouth. The corolla is white to light pink and dotted with darker pink on the lips. The protruding stamen
s are tipped with tiny horned anthers. Blooming occurs in August through October. The flowers are pollinated
by the bee-fly
Exprosopa fasciata.
A number of other Dicerandra have been separated from D. frutescens and elevated to species status, including Dicerandra cornutissima
in 1981, Dicerandra christmanii
in 1989, and Dicerandra modesta in 2008.
This plant grows in endangered Florida scrub
habitat on the botanically unique Lake Wales Ridge
. It is estimated that 74.4% of the native habitat in this area was destroyed or altered by 1981, and the process continues today. There are fourteen occurrences, and nine of them are located on private property that may be slated for development; their status is uncertain and some of them may have been destroyed. The scrub where the plant grows is yellow sand scrub dominated by either sand pine or a mix of oak
s (Quercus spp.) and scrub hickory (Carya floridana), or both types. This kind of habitat is maintained by periodic wildfire
, a process which is required to clear large and woody vegetation and provide gaps that the smaller plants, including this species, require. Fire suppression is a threat to these species.
There is little damage from disease or predation on the plants, but one species of moth
does use it as a larval host. The larva
of Pyrausta panopealis is not disturbed by the aromatic oils that keep most other insects from consuming the plant. Furthermore, the moth larva might protect itself from other insects by vomiting quantities of the irritating oil all over itself.
Lamiaceae
The mints, taxonomically known as Lamiaceae or Labiatae, are a family of flowering plants. They have traditionally been considered closely related to Verbenaceae, but in the 1990s, phylogenetic studies suggested that many genera classified in Verbenaceae belong instead in Lamiaceae...
known by the common names scrub mint and scrub balm. It is endemic to Highlands County, Florida
Highlands County, Florida
Highlands County is a county located in the U.S. state of Florida. The U.S. Census Bureau 2006 estimate for the population was 97,346. Its county seat is Sebring, Florida. The county comprises the Sebring, Florida, Micropolitan Statistical Area.- History :...
, where it is known only from the Lake Wales Ridge
Lake Wales Ridge
The Lake Wales Ridge is a low ridge running for about 150 miles south to north in Central Florida. The greater part of the ridge is in Highlands County and Polk County, but it extends north into Osceola, Orange and Lake Counties. It is named for the city of Lake Wales, roughly at the mid point of...
. Its habitat is quickly being lost as it is converted to residential and agricultural use. It was federally listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
of the United States in 1985.
This shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
grows about half a meter tall from a deep taproot
Taproot
A taproot is an enlarged, somewhat straight to tapering plant root that grows vertically downward. It forms a center from which other roots sprout laterally.Plants with taproots are difficult to transplant...
. It is glandular and strongly aromatic with a mint scent. The oblong leaves are roughly 2 centimeters long, smooth-edged, oppositely arranged, and dotted with visible oil glands. The inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is a pair of flowers each roughly 1.5 centimeters long. The flower has a tubular throat and a lobed, lipped mouth. The corolla is white to light pink and dotted with darker pink on the lips. The protruding stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s are tipped with tiny horned anthers. Blooming occurs in August through October. The flowers are pollinated
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
by the bee-fly
Bombyliidae
Bombyliidae is a large family of flies with hundreds of genera, although their life cycles are not well known. Adults generally feed on nectar and pollen, thus are pollinators of flowers. They superficially resemble bees, thus are commonly called bee flies, and this may offer the adults some...
Exprosopa fasciata.
A number of other Dicerandra have been separated from D. frutescens and elevated to species status, including Dicerandra cornutissima
Dicerandra cornutissima
Dicerandra cornutissima is a rare species of flowering plant in the mint family known by the common name longspurred mint, longspurred balm, and Robin's mint. It is endemic to Florida in the United States. It is found in Marion County, and possibly Sumter County, but it may have been totally...
in 1981, Dicerandra christmanii
Dicerandra christmanii
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...
in 1989, and Dicerandra modesta in 2008.
This plant grows in endangered Florida scrub
Florida scrub
Florida scrub is an endangered temperate coniferous forest ecoregion of the state of Florida in the United States. It is found on coastal and inland sand ridges and is characterized by a xeromorphic plant community dominated by shrubs and dwarf oaks. Scrub soils, a type of entisol, are derived...
habitat on the botanically unique Lake Wales Ridge
Lake Wales Ridge
The Lake Wales Ridge is a low ridge running for about 150 miles south to north in Central Florida. The greater part of the ridge is in Highlands County and Polk County, but it extends north into Osceola, Orange and Lake Counties. It is named for the city of Lake Wales, roughly at the mid point of...
. It is estimated that 74.4% of the native habitat in this area was destroyed or altered by 1981, and the process continues today. There are fourteen occurrences, and nine of them are located on private property that may be slated for development; their status is uncertain and some of them may have been destroyed. The scrub where the plant grows is yellow sand scrub dominated by either sand pine or a mix of oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
s (Quercus spp.) and scrub hickory (Carya floridana), or both types. This kind of habitat is maintained by periodic wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
, a process which is required to clear large and woody vegetation and provide gaps that the smaller plants, including this species, require. Fire suppression is a threat to these species.
There is little damage from disease or predation on the plants, but one species of moth
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
does use it as a larval host. The larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
of Pyrausta panopealis is not disturbed by the aromatic oils that keep most other insects from consuming the plant. Furthermore, the moth larva might protect itself from other insects by vomiting quantities of the irritating oil all over itself.