''Geocarpon'' is a monotypic genusUSFWS
Threatened status for ''Geocarpon minimum''.
''Federal Register'' June 16, 1987.USFWS
''Geocarpon minimum'' Five-year Review.
July 2009.''Geocarpon''.
Flora of North America. of flowering plants in the family

Caryophyllaceae 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, Cactacea ...

. It contains 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 ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...

Missouri Missouri 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 is bordered by eight states (tied for the most with Tennessee ...

, and

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

. 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 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 micropol ...

, 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 an area, 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 meteorologic ...

changed, and it now exists as a

relict species In biogeography and paleontology, a relict is a population or taxon of organisms that was more widespread or more diverse in the past. A relictual population is a population currently inhabiting a restricted area whose range was far wider during a ...

in a narrow strip of hospitable habitat. It grows on

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

glade Glade may refer to: Computing *Glade Interface Designer, a GUI designer for GTK+ and GNOME Geography *Glade (geography), open area in woodland, synonym for "clearing" **Glade skiing, skiing amongst trees ;Places in the United States *Glade, Kansa ...

s and

outcrop An outcrop or rocky 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 ...

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 composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.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 vari ...

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

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 lichen in the family Parmeliaceae.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, ''Xanthoparmelia'' is syn ...

'' 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'', meani ...

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 color that is variously defined as pinkish- purplish-red, reddish-purplish-pink or mauvish-crimson. On color wheels of the RGB (additive) and CMY (subtractive) color models, it is located exactly midway between red and blue. I ...

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

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

s.''Geocarpon minimum''.

The Nature Conservancy The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US. Founded in 1951, The Natu ...

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

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. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

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 material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition ...

, 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 roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...

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, sometimes referred to as an overland or adventure 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 dee ...

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 study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps wi ...

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 i ...

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 plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is d ...

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, from1=Q15941137, from2=Q5533958 Caryophyllaceae Endemic flora of the United States Flora of Arkansas Flora of Louisiana Flora of Missouri Flora of Texas Monotypic Caryophyllaceae genera Taxa named by Kenneth Kent Mackenzie Endangered flora of the United States