Helianthella uniflora

{{Short description|Species of flowering plant}}

{{Speciesbox

| image = Helianthella uniflora (5384590185).jpg

| status = {{TNCStatus}}

| status_system = TNC

| genus = Helianthella

| species = uniflora

| authority = (Nutt.) Torr. & A.Gray 1842

| synonyms_ref = [http://www.theplantlist.org/tpl1.1/record/gcc-39182 The Plant List, Helianthella uniflora (Nutt.) Torr. & A. Gray ]

| synonyms = *Helianthus uniflorus Nutt. 1834

• Leighia uniflora (Nutt.) Nutt.
• Helianthella douglasii Torr. & A.Gray

}}

Helianthella uniflora, the oneflower helianthella,{{PLANTS|id=HEUN|taxon=Helianthella uniflora|accessdate=20 July 2015}} is a North American plant species in the family Asteraceae. It grows in the western United States and western Canada. It has been found from British Columbia south as far as northern Arizona and northern New Mexico.[http://bonap.net/MapGallery/County/Helianthella%20uniflora.png Biota of North America Program 2014 county distribution map][http://swbiodiversity.org/seinet/taxa/index.php?taxon=18307&taxauthid=1 SEINet, Southwestern Biodiversity, Arizona chapter] includes photos, description, distribution map

Helianthella uniflora is a herbaceous plant up to {{convert|120|cm|ft|abbr=on}} tall. Leaves are up to {{convert|25|cm|in|abbr=on}} long, each with 3 prominent veins running the length of the leaf. The plant usually produces only one yellow flower head per stem, though sometimes 2 or 3, the heads not nodding (hanging). Each head contains 11-21 bright yellow ray flowers surrounding numerous yellow disc flowers.[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=220006163 Flora of North America, Helianthella uniflora (Nuttall) Torrey & A. Gray, 1842. ]