Helianthus praecox

{{Short description|Species of sunflower}}

{{Speciesbox

|image = Helianthus praecox, Rockport, TX 78382, USA imported from iNaturalist photo 400115309.jpg

|status = LC

|status_system = IUCN3.1

|genus = Helianthus

|species = praecox

|authority = Engelm. & A.Gray

|synonyms_ref = [http://www.theplantlist.org/tpl1.1/record/gcc-7554 The Plant List, Helianthus praecox Engelm. & A.Gray ]

|synonyms = {{collapsible list|bullets = true

|title=Synonymy

|Helianthus cucumerifolius var. praecox (Engelm. & A.Gray) A.Gray

|Helianthus debilis subsp. praecox (Engelm. & A.Gray) Heiser

|Helianthus debilis subsp. hirtus Heiser, syn of subsp. hirtus

|Helianthus debilis subsp. runyonii Heiser, syn of subsp. runyonii

|Helianthus praecox var. runyonii (Heiser) B.L.Turner, syn of subsp. runyonii

|}}

}}

Helianthus praecox is a North American species of sunflower known by the common name Texas sunflower. It is endemic to Texas. Most of the populations are either along the Gulf Coast or in the Río Grande Valley.[http://bonap.net/MapGallery/County/Helianthus%20praecox.png Biota of North America Program 2014 county distribution map]

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, each containing 11-16 yellow ray florets surrounding 35 or more red or purple disc florets.[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250066896 Flora of North America, Helianthus praecox Engelmann & A. Gray, 1847. Texas sunflower ]

;Subspecies[http://www.phytologia.org/uploads/2/3/4/2/23422706/962107-109turner_helianthus_texas_sunflower.pdf Billie 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
• Helianthus praecox subsp. praecox - sandy soils along the coast in Galveston County + Brazoria County
• Helianthus praecox subsp. runyonii (Heiser) Heiser - Coastal prairies (from Calhoun County to Cameron County) and Río Grande Valley (from Webb County to Cameron County)