Helianthus decapetalus

L.

Thinleaf Sunflower

G5Secure Found in 11 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.161306
Element CodePDAST4N0F0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderAsterales
FamilyAsteraceae
GenusHelianthus
Other Common Names
Forest Sunflower (EN) Hélianthe à dix rayons (FR) thinleaf sunflower (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-09-12
Change Date1988-02-09
Edition Date2025-09-12
Edition AuthorsSoteropoulos (2025)
Threat ImpactUnknown
Range Extent200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Helianthus decapetalus is a wide-ranging perennial forb found in mesic to wet woodlands, oak savannas, and forest edges. It occurs in eastern North America from New Brunswick west to Ontario, Canada, south to Georgia west to Mississippi and Missouri in the United States. There are over 500 estimated occurrences, which are potentially threatened by development, rights-of-way maintenance, logging, invasive species, and other threats in some places. Little is known about trends, but with a large range extent and large number of occurrences, abundant habitat, and broad habitat preferences, this species is considered secure.
Range Extent Comments
Helianthus decapetalus occurs in eastern North America from New Brunswick west to Ontario, Canada, south to Georgia west to Mississippi and Missouri, and historically in Louisiana in the United States (FNA 2006, Weakley and the Southeastern Flora Team 2025). Range extent was estimated to be over 2.2 million square kilometers using herbarium specimens and photo-based observations documented between 1994 and 2025 (GBIF 2025, iNaturalist 2025, RARECAT 2025, SEINet 2025).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens and photo-based observations documented between 1994 and 2025, it is estimated that there are over 500 occurrences rangewide (GBIF 2025, iNaturalist 2025, RARECAT 2025, SEINet 2025).
Threat Impact Comments
Although threats are not widely documented, this species is potentially threatened by development, rights-of-way maintenance, logging, invasive species, and other threats in some places. However, their overall impact is likely negligible given the species' broad range, large number of occurrences, tolerance of light disturbance, and affinity for typically abundant habitats.
Ecology & Habitat

Habitat

Helianthus decapetalus grows in mesic to wet woodlands, oak savannas, and forest edges (FNA 2006, Weakley and the Southeastern Flora Team 2025).
Terrestrial Habitats
Forest/WoodlandForest EdgeWoodland - HardwoodWoodland - Mixed
Other Nations (2)
United StatesN5
ProvinceRankNative
IndianaSNRYes
IowaS4Yes
District of ColumbiaSNRYes
ConnecticutSNRYes
South CarolinaSNRYes
DelawareS3Yes
KentuckyS5Yes
VirginiaS5Yes
AlabamaSNRYes
MaineSNRYes
WisconsinSNRYes
Rhode IslandSNRYes
New HampshireSNRYes
OhioSNRYes
VermontS5Yes
GeorgiaS4Yes
New YorkS5Yes
MississippiS2Yes
TennesseeSNRYes
MichiganSNRYes
LouisianaSHYes
MarylandSNRYes
MissouriSUYes
MassachusettsSNRYes
IllinoisSNRYes
West VirginiaS5Yes
New JerseyS4Yes
North CarolinaS4Yes
PennsylvaniaS5Yes
CanadaN4
ProvinceRankNative
New BrunswickS1Yes
OntarioS4Yes
QuebecS3Yes
Threat Assessments
ThreatScopeSeverityTiming
Unknown/undetermined

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)Yes
Roadless Areas (11)
North Carolina (5)
AreaForestAcres
Big Indian (addition)Nantahala National Forest1,155
Boteler PeakNantahala National Forest4,205
Jarrett CreekPisgah National Forest7,485
Laurel MountainPisgah National Forest5,683
Mackey MountainPisgah National Forest5,934
Virginia (1)
AreaForestAcres
Little RiverGeorge Washington National Forest27,292
West Virginia (5)
AreaForestAcres
Cheat MountainMonongahela National Forest8,191
Dry River (WV)George Washington National Forest7,331
Gauley MountainMonongahela National Forest13,285
Mcgowan MountainMonongahela National Forest10,504
Tea Creek MountainMonongahela National Forest8,295
References (7)
  1. Flora of North America Editorial Committee (FNA). 2006c. Flora of North America north of Mexico. Vol. 21. Magnoliophyta: Asteridae, part 8: Asteraceae, part 3. Oxford Univ. Press, New York. xxii + 616 pp.
  2. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  3. iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
  4. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  5. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  6. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
  7. Weakley, A.S., and Southeastern Flora Team. 2025. Flora of the southeastern United States Web App. Edition of February 18, 2025. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. Online. Available: https://fsus.ncbg.unc.edu (accessed 2025).