''Geocarpon minimum'' is a species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the carnation family (

Caryophyllaceae Caryophyllaceae, commonly called the pink family or carnation family, is a family (biology), family of flowering plants. It is included in the dicotyledon order Caryophyllales in the APG III system, alongside 33 other families, including Amaranth ...

) 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 ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...

, and

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

.USFWS
''Geocarpon minimum'' Five-year Review.
July 2009.''Geocarpon''.
Flora of North America. There are a number of threats to its survival and it was listed as a threatened species of the United States in 1987.USFWS
Threatened status for ''Geocarpon minimum''.
''Federal Register'' June 16, 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 is a county in the U.S. state of Texas. Located within East Texas, its county seat is Palestine. As of the 2020 United States census, the population of Anderson County was 57,922. Anderson County comprises the Palestine microp ...

, in 2004.''Geocarpon minimum''.
Texas Parks and Wildlife. The plant was probably widespread on the North American continent long ago, but the

climate Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteoro ...

changed, and it now exists as a relict species in a narrow strip of hospitable habitat. It grows on

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

glades and

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets. Features Outcrops do not cover the majority of the Earth's land surface because in most p ...

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 A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

s and ''

Nostoc ''Nostoc'', also known as star jelly, troll's butter, spit of moon, fallen star, witch's butter (not to be confused with the fungi commonly known as witches' butter), and witch's jelly, is the most common genus of cyanobacteria found in a variety ...

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

that are very wet after winter rain and then dry into a hard crust. Lichens of genus ''

Xanthoparmelia ''Xanthoparmelia'' (commonly known as green rock shields or rock-shield lichens) is a genus of foliose lichens in the family Parmeliaceae.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, This genus of lichen i ...

'' occur on the slicks.''Geocarpon minimum''.
Center for Plant Conservation. Few flowering plants grow in this harsh habitat. It is an

ephemeral Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...

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. ''Geocarpon minimum'' is a petite

succulent plant In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meanin ...

measuring no more than 4 centimeters (1.6 inches) tall with a hair-thin stem. The plant is grayish, brownish, or green when new and then turns

magenta Magenta () is a purple-red color. On color wheels of the RGB color model, RGB (additive) and subtractive color, CMY (subtractive) color models, it is located precisely midway between blue and red. It is one of the four colors of ink used in colo ...

, red, bright pink, or purplish as it matures. The red color is from

anthocyanin Anthocyanins (), also called anthocyans, are solubility, water-soluble vacuole, vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart named a chemical compou ...

s.''Geocarpon minimum''.

The Nature Conservancy The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia, United States. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US. Founded in ...

. It has tiny leaves 3 or 4 millimeters long and a red or purplish

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

containing one flower no more than 4 millimeters long.''Geocarpon minimum''.
Flora of North America.Mackenzie, Kenneth Kent 1914. Torreya 14(4): 67–68
/ref> ''Geocarpon minimum'' 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 Fire is the rapid oxidation of a fuel in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. Flames, the most visible portion of the fire, are produced in the combustion re ...

, to stay bare, eroded, and salty. However, too much disturbance can destroy this type of habitat. For example, cattle

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to free range (roam around) and consume wild vegetations in order to feed conversion ratio, convert the otherwise indigestible (by human diges ...

tends to alter the soil in such a way that plants can take hold, turning bare patches to

prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...

, but there is also evidence that intensive grazing can keep larger plants down and allow the tinytim to spring up.

Off-road vehicle An off-road vehicle (ORV), also known as an off-highway vehicle (OHV), overland vehicle or adventure vehicle, is a type of transportation specifically engineered to navigate unpaved roads and surfaces. These include trails, forest roads, and ...

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 () is the natural science of the relationships among living organisms and their environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere levels. Ecology overlaps with the closely re ...

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 is either the presence of, or the generation of, genetic differences. It is defined as "the formation of individuals differing in genotype, or the presence of genotypically different individuals, in contrast to environmentally ...

of the species across its range. There has been some disagreement over which family this genus should be assigned to. Mackenzie in his initial description placed it in the

Aizoaceae The Aizoaceae (), or fig-marigold family, is a large family of dicotyledonous flowering plants containing 135 genera and about 1,800 species. Several genera are commonly known as 'ice plants' or 'carpet weeds'. The Aizoaceae are also referred to a ...

but most present-day taxonomists regard it as part of the

.Bogle, A. L., T. Swain, R. D. Thomas, and E. D. Kohn. 1971. ''Geocarpon:'' Aizoaceae or Caryophyllaceae? Taxon 20: 473-477

References

External links

USDA Plants Profile for ''Geocarpon minimum''
{{Taxonbar, from=Q5533958 Caryophyllaceae Endemic flora of the United States Flora of Arkansas Flora of Louisiana Flora of Missouri Flora of Texas Taxa named by Kenneth Kent Mackenzie Endangered flora of the United States