Geocarpon
Encyclopedia
Geocarpon is a monotypic genus of flowering plants in the pink family
containing the single species Geocarpon minimum, which is known by the common names tinytim and earth-fruit. It is a rare plant known from about 34 populations in the US states of Arkansas
, Louisiana
, Missouri
, and Texas
. There are a number of threats to its survival and it was listed as a threatened species of the United States in 1987.
Most of the populations are located in Missouri, with a few more in Arkansas and Louisiana. It was discovered in Anderson County, Texas
, in 2004. The plant was probably widespread on the North American continent long ago, but the climate
changed, and it now exists as a relict species in a narrow strip of hospitable habitat. It grows on sandstone
glade
s and outcrop
s as well as bare, sparsely vegetated areas where the soil contains relatively large amounts of magnesium and sodium salts. It can be found on "slicks" with a coating of lichen
s and Nostoc
cyanobacteria that are very wet after winter rain and then dry into a hard crust. Lichens of genus Xanthoparmelia
occur on the slicks. Few flowering plants grow in this harsh habitat. It is an ephemeral
species, sprouting up and generally undergoing its full life cycle within four weeks around February and March, or as late as June in some areas. The yearly abundance of this tiny annual plant in a particular area depends on the amount of recent rainfall there; populations are small or nonexistent in dry years and can contain thousands of plants in a wet season.
This is a petite succulent plant
measuring no more than 4 centimeters tall with a hair-thin stem. The plant is grayish, brownish, or green when new and then turns magenta
, red, bright pink, or purplish in color as it matures. The red color is from anthocyanin
s. It has tiny leaves 3 or 4 millimeters long and a red or purplish inflorescence
containing one flower no more than 4 millimeters long.
This plant requires a specific type of habitat. The slicks and saline prairies it inhabits have become uncommon as the soil has changed. As the substrate has become more suitable for other types of flowering plants, the tinytim is easily outcompeted
. What causes this change in the soils is not clear. They probably require some sort of disturbance, such as fire
, to stay bare, eroded, and salty. However, too much disturbance can destroy this type of habitat. For example, cattle grazing
tends to alter the soil in such a way that plants can take hold, turning bare patches to prairie
, but there is also evidence that intensive grazing can keep larger plants down and allow the tinytim to spring up. Off-road vehicle
s have been noted to destroy habitat, but the type of disturbance they create may also be helpful in keeping the soil barren. More research may help clarify the ecological
relationships of the plant.
Although the tinytim is still quite limited in range and minor threats still exist, it has a "high recovery potential" and is almost ready to be removed from the endangered species list. Since it was listed, more populations have been discovered and a few have been planted in appropriate habitat. However, the populations require more monitoring to make sure they can survive and research should be done to establish the genetic variability
of the species across its range.
Caryophyllaceae
The Caryophyllaceae, commonly called the pink family or carnation family, is a family of flowering plants. It is included in the dicotyledon order Caryophyllales in the APG III system, alongside 33 other families, including Amaranthaceae, Cactaceae and Polygonaceae...
containing the single species Geocarpon minimum, which is known by the common names tinytim and earth-fruit. It is a rare plant known from about 34 populations in the US states of Arkansas
Arkansas
Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...
, Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
, Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
, and Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
. There are a number of threats to its survival and it was listed as a threatened species of the United States in 1987.
Most of the populations are located in Missouri, with a few more in Arkansas and Louisiana. It was discovered in Anderson County, Texas
Anderson County, Texas
Anderson County is a county located in the U.S. state of Texas. As of 2000, the population was 55,109. Its county seat is Palestine. Anderson county was organized in 1846, and is named in honor of Kenneth L. Anderson who had been Vice President of the Republic of Texas.-Geography:According to the...
, in 2004. The plant was probably widespread on the North American continent long ago, but the climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
changed, and it now exists as a relict species in a narrow strip of hospitable habitat. It grows on sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
glade
Glade
-Geography:*Glade , open area in woodland, synonym for "clearing"**Glade skiing, skiing amongst treesPlaces in the United States*Glade, California, a former town in Lassen County*Glade, Kansas, a city in Phillips County...
s and outcrop
Outcrop
An outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. -Features:Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by a mantle of soil and vegetation and cannot be...
s as well as bare, sparsely vegetated areas where the soil contains relatively large amounts of magnesium and sodium salts. It can be found on "slicks" with a coating of lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
s and Nostoc
Nostoc
Nostoc is a genus of cyanobacteria found in a variety of environmental niches that forms colonies composed of filaments of moniliform cells in a gelatinous sheath.The name "Nostoc" was invented by Paracelsus...
cyanobacteria that are very wet after winter rain and then dry into a hard crust. Lichens of genus Xanthoparmelia
Xanthoparmelia
Xanthoparmelia is a genus of lichen belonging to the family Parmeliaceae. Xanthoparmelia is synonymous with Almbornia, Neofuscelia, Chondropsis, Namakwa, Paraparmelia, and Xanthomaculina.This family of lichen is commonly found on the mid-east coast of the United States.The name means 'golden...
occur on the slicks. Few flowering plants grow in this harsh habitat. It is an ephemeral
Ephemeral
Ephemeral things are transitory, existing only briefly. Typically the term is used to describe objects found in nature, although it can describe a wide range of things....
species, sprouting up and generally undergoing its full life cycle within four weeks around February and March, or as late as June in some areas. The yearly abundance of this tiny annual plant in a particular area depends on the amount of recent rainfall there; populations are small or nonexistent in dry years and can contain thousands of plants in a wet season.
This is a petite succulent plant
Succulent plant
Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climates or soil conditions. Succulent plants store water in their leaves, stems, and also in roots...
measuring no more than 4 centimeters tall with a hair-thin stem. The plant is grayish, brownish, or green when new and then turns magenta
Magenta
Magenta is a color evoked by light stronger in blue and red wavelengths than in yellowish-green wavelengths . In light experiments, magenta can be produced by removing the lime-green wavelengths from white light...
, red, bright pink, or purplish in color as it matures. The red color is from anthocyanin
Anthocyanin
Anthocyanins are water-soluble vacuolar pigments that may appear red, purple, or blue according to pH...
s. It has tiny leaves 3 or 4 millimeters long and a red or purplish 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...
containing one flower no more than 4 millimeters long.
This plant requires a specific type of habitat. The slicks and saline prairies it inhabits have become uncommon as the soil has changed. As the substrate has become more suitable for other types of flowering plants, the tinytim is easily outcompeted
Competition (biology)
Competition is an interaction between organisms or species, in which the fitness of one is lowered by the presence of another. Limited supply of at least one resource used by both is required. Competition both within and between species is an important topic in ecology, especially community ecology...
. What causes this change in the soils is not clear. They probably require some sort of disturbance, such as fire
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...
, to stay bare, eroded, and salty. However, too much disturbance can destroy this type of habitat. For example, cattle grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
tends to alter the soil in such a way that plants can take hold, turning bare patches to prairie
Prairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...
, but there is also evidence that intensive grazing can keep larger plants down and allow the tinytim to spring up. Off-road vehicle
Off-road vehicle
An off-road vehicle is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface. It is generally characterized by having large tires with deep, open treads, a flexible suspension, or even caterpillar tracks...
s have been noted to destroy habitat, but the type of disturbance they create may also be helpful in keeping the soil barren. More research may help clarify the ecological
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
relationships of the plant.
Although the tinytim is still quite limited in range and minor threats still exist, it has a "high recovery potential" and is almost ready to be removed from the endangered species list. Since it was listed, more populations have been discovered and a few have been planted in appropriate habitat. However, the populations require more monitoring to make sure they can survive and research should be done to establish the genetic variability
Genetic variability
Genetic variability is a measure of the tendency of individual genotypes in a population to vary from one another. Variability is different from genetic diversity, which is the amount of variation seen in a particular population. The variability of a trait describes how much that trait tends to...
of the species across its range.