Thymophylla tephroleuca (formerly Dyssodia tephroleuca) is a rare species of flowering plant known by the common names ashy pricklyleafand ashy dogweed. It is endemic to Texas in the United States, where it occurs in two counties near the Mexican border. It became rare due to the destruction and degradation of its habitat. It is a federally listed endangered species of the United States.
Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. The extreme opposite of endemism is cosmopolitan distribution. An alternative term for a species that is endemic is precinctive, which applies to species that are restricted to a defined geographical area.
Texas is the second largest state in the United States by both area and population. Geographically located in the South Central region of the country, Texas shares borders with the U.S. states of Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the west, and the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas to the southwest, while the Gulf of Mexico is to the southeast.
An endangered species is a species which has been categorized as very likely to become extinct. Endangered (EN), as categorized by the International Union for Conservation of Nature (IUCN) Red List, is the second most severe conservation status for wild populations in the IUCN's schema after Critically Endangered (CR).
This plant, a shrub or subshrub, produces a clump of stems up to 30 centimeters tall. The herbage is ashy gray-green, gray, or whitish due to a layer of white woolly hairs. The leaves are linear to threadlike and are arranged alternately along the stems. They measure 1 to 1.5 centimeters long. The inflorescence is a flower head with a bell-shaped involucre of woolly-haired phyllaries. There are 12 or 13 yellow ray florets and about 30 disc florets at the center. The fruit is an achene with a pappus of scales.Blooming occurs mostly in March through May but it may bloom at other times depending on rainfall.
A shrub or bush is a small- to medium-sized woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. They are distinguished from trees by their multiple stems and shorter height, and are usually under 6 m (20 ft) tall. Plants of many species may grow either into shrubs or trees, depending on their growing conditions. Small, low shrubs, generally less than 2 m (6.6 ft) tall, such as lavender, periwinkle and most small garden varieties of rose, are often termed "subshrubs".
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. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes. Inflorescence can also be defined as the reproductive portion of a plant that bears a cluster of flowers in a specific pattern.
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture. Typically, they also look different from the parts of the flower, such as the petals or sepals. The state of having bracts is referred to as bracteate or bracteolate, and conversely the state of lacking them is referred to as ebracteate and ebracteolate, without bracts.
T. tephroleuca prefers fine sand or sandy-loam soils.Its current habitat is predominately shrub-invaded grasslands.
This plant is likely a relict, a rare species remaining in a grassland habitat type that was once more common.Most of the local territory has converted to brushland dominated by cenizo (Leucophyllum frutescens) blackbrush (Coleogyne ramosissima), and creosote bush (Larrea tridentata). Other dominant plant species include mesquite (Prosopis glandulosa), goatbush (Castela texana), anacahuita (Cordia boissieri), and javelina brush (Microrhamnus ericoides). The introduced buffelgrass (Cenchrus ciliaris) is common.
A relict is a surviving remnant of a natural phenomenon.
Grasslands are areas where the vegetation is dominated by grasses (Poaceae); however, sedge (Cyperaceae) and rush (Juncaceae) families can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica. Grasslands are found in most ecoregions of the Earth. For example, there are five terrestrial ecoregion classifications (subdivisions) of the temperate grasslands, savannas, and shrublands biome (ecosystem), which is one of eight terrestrial ecozones of the Earth's surface.
Leucophyllum frutescens is an evergreen shrub in the figwort family, Scrophulariaceae, native to the state of Texas in the southwestern United States and the states of Coahuila, Nuevo León, and Tamaulipas in northern Mexico. Although commonly known as Texas sage, it is not a true sage and is distinct from the genus Salvia. The species is also called Texas Ranger, Texas rain sage, cenizo, Texas silverleaf, Texas barometerbush, ash-bush, wild lilac, purple sage, senisa, cenicilla, palo cenizo, or hierba del cenizo.
By 1979 this plant was known from a 1-acre (0.0040 km2) in Zapata County, Texas. By the time the plant was placed on the Endangered Species List in 1984, there was a single population containing about 1300 plants bisected by a highway. More populations have been found in the years since, and currently there are six in Zapata and Webb Counties.
Zapata County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 14,018. Its county seat is Zapata. The county is named for Colonel Jose Antonio de Zapata, a rancher in the area who rebelled against Mexico.
Webb County is a county located in the U.S. state of Texas. As of the 2010 census, the population was 250,304. Its county seat is Laredo. The county was named after James Webb, who served as Secretary of the Treasury, Secretary of State, and Attorney General of the Republic of Texas, and later judge of the United States District Court following the admission of Texas to statehood. By area, Webb County is the largest county in South Texas and the sixth largest in the state.
Highway maintenance is an ongoing threat to the species, as the plant grows directly next to a highway. Dying plants have been observed at the highway's edge, a possible sign of herbicide application. The installation of a gas pipeline likely destroyed some plants and its maintenance is a threat to others in the area. Grazing is not a direct threat because cattle do not eat the foul-smelling plant, but their trampling may compact the soil. The introduction of buffelgrass for better grazing has led to drastic changes in the plant community, because it spreads and competes easily with other species.
Herbicides, British English: ), also commonly known as weedkillers, are chemical substances used to control unwanted plants. Selective herbicides control specific weed species, while leaving the desired crop relatively unharmed, while non-selective herbicides can be used to clear waste ground, industrial and construction sites, railways and railway embankments as they kill all plant material with which they come into contact. Apart from selective/non-selective, other important distinctions include persistence, means of uptake, and mechanism of action. Historically, products such as common salt and other metal salts were used as herbicides, however these have gradually fallen out of favor and in some countries a number of these are banned due to their persistence in soil, and toxicity and groundwater contamination concerns. Herbicides have also been used in warfare and conflict.
Grazing is a method of feeding in which a herbivore feeds on plants such as grasses, or other multicellular organisms such as algae. In agriculture, grazing is one method used whereby domestic livestock are used to convert grass and other forage into meat, milk and other products.
Cenchrus ciliaris is a species of grass native to most of Africa, southern Asia, southern Iran, and the extreme south of Europe (Sicily). Other names by which this grass is known include dhaman grass, anjan grass and koluk katai.
Echinacea laevigata, the smooth purple coneflower, is an Endangered Species Act federally listed endangered species of plant found in the piedmont of the eastern United States. Most populations are found on roadsides and other open areas with plenty of sunlight, often on calcium- and magnesium- rich soils.
Thymophylla is a genus of perennial flowering plants in the marigold tribe within the sunflower family. Pricklyleaf is a common name for plants in this genus.
Krascheninnikovia lanata is a species of flowering plant in the amaranth family (Amaranthaceae), known by the common name winterfat. It is native to much of western North America: from central Western Canada; through the Western United States; to northern Mexico.
Dyssodia Cav. is a small genus of flowering plants in the daisy family. Most dyssodias are now treated as members of other related genera, including Thymophylla or Adenophyllum, with Dyssodia as genus synonym. Dyssodia papposa is usually retained in this genus. The name is derived from the Greek δυσοδια (dusodia), meaning "ill-smelling".
Blennosperma bakeri is a rare species of flowering plant in the daisy family known by the common names Baker's stickyseed and Sonoma sunshine. It is endemic to Sonoma County, California, where it is known from a few remaining vernal pool sites on the wet grasslands of the Laguna de Santa Rosa and Sonoma Valley. It is a federally listed endangered species. It is found alongside other rare vernal pool plants including the Sebastopol meadowfoam, Limnanthes vinculans, and Burke's goldfields, Lasthenia burkei. Threats to its survival include the alteration of its habitat for development, road maintenance, grazing, and agriculture, as well as collecting, herbivory by thrips, and invasive plants.
Pseudobahia bahiifolia is a rare species of flowering plant in the aster family known by the common name Hartweg's golden sunburst.
Pseudobahia peirsonii is a rare species of flowering plant in the aster family known by the common names San Joaquin adobe sunburst and Tulare pseudobahia. It is endemic to California, where it is known from a few mostly small occurrences along the southeastern side of the San Joaquin Valley where it rises into the Sierra Nevada foothills. It grows in grassland and oak woodland habitat. It prefers heavy adobe clay soils. The plant became a federally listed threatened of the United States in 1997.
Packera layneae, known by the common name Layne's ragwort and Layne's butterweed, is a rare species of flowering plant in the aster family.
Ambrosia cheiranthifolia is a rare species of flowering plant known by the common names South Texas ambrosia and Rio Grande ragweed. It is native to the coast of South Texas and the Mexican states of Tamaulipas and Coahuila. It occurs in coastal prairie, grassland, and mesquite shrubland habitat. It has declined because its native habitat has been cleared for development, with remaining open savanna invaded by non-native grasses such as buffelgrass. Today there are perhaps 20 populations remaining, but some of these may have very few genetic individuals because the species is clonal, with many cloned plants attached by one rhizome. It is not certain that the plant still exists in Mexico. This is a federally listed endangered species of the United States.
Aristida portoricensis is a rare species of grass known by the common name pelos del diablo. It is endemic to Puerto Rico, where it is known from two locations, one in a residential area of Mayagüez and one in the Sierra Bermeja. Two other known sites have been extirpated by development of the habitat. It is a federally listed endangered species of the United States.
Astragalus holmgreniorum is a rare species of milkvetch known by the common names Holmgren milkvetch and paradox milkvetch. It is native to a tiny section of desert shrub woodland on the border between Utah and Arizona, in the far northern Mojave Desert. There are six populations remaining. It is a federally listed endangered species.
Chrysopsis floridana is a rare species of flowering plant in the aster family, known by its common name, Florida golden aster. It is endemic to Florida in the United States, where it is known from Hillsborough, Hardee, Manatee, and Pinellas Counties. It is considered an endemic of the west-central coast of the state in the general vicinity of Tampa Bay. There are 17 to 20 occurrences, many of which have few individuals, but one of which has over one million plants. In 1986 the plant was added to the US endangered species list because it was becoming increasingly rare, it was growing only on private property, and its habitat was unprotected and being destroyed and degraded by a number of forces. It is found at Bell Creek Nature Preserve in Riverview, Florida.
Escobaria robbinsiorum is a rare species of cactus known by the common names Cochise pincushion cactus and Cochise foxtail cactus. It is native to southern Arizona in the United States, where it is known only from Cochise County, and northern Sonora in Mexico. There are scattered small occurrences on the north side of the border, and one known population to the south. Because of its rarity and a number of threats to remaining plants, the species was federally listed with a threatened status in 1986.
Erigeron rhizomatus is a rare species of flowering plant in the aster family known by the common names Zuni fleabane and rhizome fleabane. It is native to western New Mexico and eastern Arizona in the United States. It is a federally listed threatened species.
Frankenia johnstonii is a species of flowering plant known by the common name Johnston's seaheath, or Johnston's frankenia. It is native to southern Texas in the United States and northern Nuevo León in Mexico, where there are about 30 occurrences known. The plant was federally listed as an endangered species in the United States in 1984. It was found to be more abundant than previously thought and it was proposed for delisting in 2003.
Hymenoxys texana is a rare species of flowering plant in the aster family known by the common names prairie dawn, Texas prairie dawn-flower, and Texas bitterweed. It is endemic to Texas, where it is known only from the general vicinity of Houston. It is threatened by the loss of its habitat. It is a federally listed endangered species of the United States.
Phacelia argillacea is a rare species of flowering plant in the borage family known by the common names clay phacelia and Atwood's phacelia. It is endemic to Utah in the United States, where it is known only from one canyon in Utah County. It is "one of Utah's most endangered species"; it is "one of the nation's rarest plants" and is federally listed as an endangered species of the United States.
Spiranthes delitescens is a rare species of orchid known by the common names reclusive lady's tresses, Canelo Hills lady's tresses, and Madrean lady's tresses. It is native to Arizona in the United States, where there are only four occurrences. It is threatened by the loss and degradation of its habitat. It is a federally listed endangered species of the United States.
Townsendia aprica is a rare species of flowering plant in the aster family known by the common name Last Chance Townsend daisy. It is endemic to Utah in the United States, where it is known from three counties. It faces a number of threats and it is a federally listed threatened species of the United States.
Physaria thamnophila is a rare species of flowering plant in the mustard family known by the common name Zapata bladderpod. It is native to Texas in the United States, where it is known from Zapata and Starr Counties. The plant is threatened by the loss and degradation of its habitat. It is federally listed as an endangered species.