Polygala smallii
Encyclopedia
Polygala smallii is a rare species of flowering plant in the milkwort family
known by the common name tiny polygala, or tiny milkwort. It is endemic to Florida
in the United States, where it is limited to the southeastern coast of the peninsula. The plant is now only known from eight sites, with most individuals located on one site in Miami-Dade County
. The species is threatened by the loss of its habitat. This is a federally listed endangered species
of the United States.
The plant is a petite biennial herb growing 2 to 4 centimeters tall from the top of its taproot
. The leaves are spatula
-shaped and form a rosette at the base of the stems. They are closely packed and measure up to about 3.5 centimeters in length. The top of each stem is occupied by a short inflorescence
of yellow-green flowers. The inflorescence often does not exceed the length of the leaf rosette. The plants have an aboveground lifespan of about 180 days, after which they disappear until the next wildfire
sweeps the area.
This plant grows in Florida scrub
and pine rockland habitat in Miami-Dade, Palm Beach
, St. Lucie
, and Martin Counties
in Florida. It occurs on public property occupied by Zoo Miami and adjacent United States Coast Guard
property. 10,000 plants have been counted at the latter site, the largest population of the plant. It has been noted at the Fort Lauderdale Executive Airport
in a preserve established there for the gopher tortoise. The species has a cyclic life cycle
and may exist at sites where it has not been seen recently.
The habitat occupied by this plant is maintained by a natural fire regime
. Fire helps the plant by removing competing plants. It requires open spaces with sunlight and tolerates disturbance, and it resprouts readily after wildfire has affected the habitat. At times, it has been positively affected by the disturbance created during hurricanes. The long-term practice of fire suppression in the region has allowed the plant's habitat to become overgrown with large and woody vegetation. Habitat conservation
must involve periodic prescribed burns or another method of opening the overgrown canopy. Fire is also beneficial because it may trigger germination
of the seeds: experiments showed 50% more germination and faster germination in seeds that had been exposed to smoke. Seeds persist in a soil seed bank
until they are prompted to germinate.
Another main threat to the species is the outright consumption of its habitat for the construction of residential and commercial real estate.
Polygalaceae
The Polygalaceae or Milkwort family is a family of flowering plants in the order Fabales. They have a near-cosmopolitan range, with about 17 genera and 900–1,000 species of herbs, shrubs and trees...
known by the common name tiny polygala, or tiny milkwort. It is endemic to Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
in the United States, where it is limited to the southeastern coast of the peninsula. The plant is now only known from eight sites, with most individuals located on one site in Miami-Dade County
Miami-Dade County, Florida
Miami-Dade County is a county located in the southeastern part of the state of Florida. As of 2010 U.S. Census, the county had a population of 2,496,435, making it the most populous county in Florida and the eighth-most populous county in the United States...
. The species is threatened by the loss of its habitat. This is a federally listed 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.
The plant is a petite biennial herb growing 2 to 4 centimeters tall from the top of its 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...
. The leaves are spatula
Spatula
The term spatula is used to refer to various small implements with a broad, flat, flexible blade used to mix, spread and lift materials including foods, drugs, plaster and paints...
-shaped and form a rosette at the base of the stems. They are closely packed and measure up to about 3.5 centimeters in length. The top of each stem is occupied by a short 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...
of yellow-green flowers. The inflorescence often does not exceed the length of the leaf rosette. The plants have an aboveground lifespan of about 180 days, after which they disappear until the next 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...
sweeps the area.
This plant grows in 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...
and pine rockland habitat in Miami-Dade, Palm Beach
Palm Beach County, Florida
Palm Beach County is the largest county in the state of Florida in total area, and third in population. As of 2010, the county's estimated population was 1,320,134, making it the twenty-eighth most populous in the United States...
, St. Lucie
St. Lucie County, Florida
St. Lucie County is a county located in the state of Florida. The county seat is the city of Fort Pierce. In the year 2000, the population was 192,695. As of the year 2010, the United States Census Bureau sets the population at 277,789.- History :...
, and Martin Counties
Martin County, Florida
Martin County is a county in the U.S. state of Florida. As of 2000, the population was 126,731. The U.S. Census Bureau 2008 estimate for the county is 138,660. Its county seat is Stuart, Florida.- History :...
in Florida. It occurs on public property occupied by Zoo Miami and adjacent United States Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
property. 10,000 plants have been counted at the latter site, the largest population of the plant. It has been noted at the Fort Lauderdale Executive Airport
Fort Lauderdale Executive Airport
Fort Lauderdale Executive Airport is a general aviation airport located within the city limits of Fort Lauderdale, in Broward County, Florida, United States, five miles north of downtown Fort Lauderdale...
in a preserve established there for the gopher tortoise. The species has a cyclic life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
and may exist at sites where it has not been seen recently.
The habitat occupied by this plant is maintained by a natural fire regime
Fire regime
A fire regime is the pattern, frequency and intensity of the bushfires and wildfires that prevails in an area. It is an integral part of fire ecology, and renewal for certain types of ecosystems. If fires are too frequent, plants may be killed before they have matured, or before they have set...
. Fire helps the plant by removing competing plants. It requires open spaces with sunlight and tolerates disturbance, and it resprouts readily after wildfire has affected the habitat. At times, it has been positively affected by the disturbance created during hurricanes. The long-term practice of fire suppression in the region has allowed the plant's habitat to become overgrown with large and woody vegetation. Habitat conservation
Habitat conservation
Habitat conservation is a land management practice that seeks to conserve, protect and restore, habitat areas for wild plants and animals, especially conservation reliant species, and prevent their extinction, fragmentation or reduction in range...
must involve periodic prescribed burns or another method of opening the overgrown canopy. Fire is also beneficial because it may trigger germination
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
of the seeds: experiments showed 50% more germination and faster germination in seeds that had been exposed to smoke. Seeds persist in a soil seed bank
Soil Seed Bank
The soil seed bank refers to the natural storage of seeds, often dormant, within the soil of most ecosystems. The study of soil seed banks started in 1859 when Charles Darwin observed the emergence of seedlings using soil samples from the bottom of a lake. The first scientific paper on the subject...
until they are prompted to germinate.
Another main threat to the species is the outright consumption of its habitat for the construction of residential and commercial real estate.