''Helianthus praecox'' is a North American species of

sunflower The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ...

known by the common name Texas sunflower. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

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 ...

. Most of the populations are either along the

Gulf Coast The Gulf Coast of the United States, also known as the Gulf South, is the coastline along the Southern United States where they meet the Gulf of Mexico. The coastal states that have a shoreline on the Gulf of Mexico are Texas, Louisiana, Mississ ...

or in the Río Grande Valley. ''Helianthus praecox'' grows on sandy soils and coastal prairies. It is an annual herb up to 150 cm (60 inches or 5 feet) tall. One plant usually produces 1-3

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

, each containing 11-16 yellow

ray florets The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

surrounding 35 or more red or purple

disc floret The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

s.Flora of North America, Helianthus praecox Engelmann & A. Gray, 1847. Texas sunflower
/ref> ;SubspeciesBillie L. Turner. 2014. Taxonomy of the Texas sunflower ''(Helianthus praecox)'' Asteraceae. Phytologia (April 1, 2014) 96(2) 107
includes county-level range map for all 3 subspecies *''Helianthus praecox'' subsp. ''hirtus'' (Heiser) Heiser - near Carrizo Springs in

Dimmit County Dimmit County ( ) is a County (United States), county located in the U.S. state of Texas. As of the 2020 United States census, 2020 census, its population was 8,615. The county seat is Carrizo Springs, Texas, Carrizo Springs. The county was fou ...

*''Helianthus praecox'' subsp. ''praecox'' - sandy soils along the coast in

Galveston County Galveston County ( ) is a county in the U.S. state of Texas, located along the Gulf Coast adjacent to Galveston Bay. As of the 2020 census, the population was 350,682. The county was founded in 1838. The county seat is the City of Galveston, ...

Brazoria County Brazoria County ( ) is a county in the U.S. state of Texas. As of the 2020 census, the population of the county was 372,031. The county seat is Angleton. Brazoria County is included in the Houston-The Woodlands-Sugar Land metropolitan statis ...

*''Helianthus praecox'' subsp. ''runyonii'' (Heiser) Heiser - Coastal prairies (from

Calhoun County Calhoun County is the name of several counties in the United States of America named after U.S. Vice President John C. Calhoun: * Calhoun County, Alabama * Calhoun County, Arkansas * Calhoun County, Florida * Calhoun County, Georgia * Calhoun Cou ...

to Cameron County) and Río Grande Valley (from

Webb County Webb County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 267,114. Its county seat is Laredo. The county was named after James Webb (1792–1856), who served as secretary of the treasury, secreta ...

to Cameron County)

References

External links

William_Carr,_University_of_Texas,_''Helianthus_praecox''_var._''runyonii''_[Asteraceae
/nowiki>_–_Runyon's_sunflower.html" ;"title="steraceae">William Carr, University of Texas, ''Helianthus praecox'' var. ''runyonii'' steraceae">William_Carr,_University_of_Texas,_''Helianthus_praecox''_var._''runyonii''_[Asteraceae
/nowiki>_–_Runyon's_sunflowerphotos Helianthus.html" ;"title="steraceae
/nowiki> – Runyon's sunflower">steraceae">William Carr, University of Texas, ''Helianthus praecox'' var. ''runyonii'' [Asteraceae
/nowiki> – Runyon's sunflowerphotos Helianthus">praecox Endemic flora of Texas Plants described in 1845 {{Heliantheae-stub