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Helianthus atrorubens

L.

Purple-disk Sunflower

G5Secure Found in 7 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.155736
Element CodePDAST4N070
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderAsterales
FamilyAsteraceae
GenusHelianthus
Other Common Names
Appalachian Sunflower (EN) Purpledisc Sunflower (EN) purpledisk 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 Date2025-11-04
Change Date1988-08-04
Edition Date2025-11-04
Edition AuthorsMorse, Larry E. (2003), rev. Soteropoulos (2025)
Threat ImpactUnknown
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Helianthus atrorubens is a wide-ranging perennial herb found in dry woodlands and roadsides. It is endemic to the southeastern United States from Virginia and Kentucky south to central Georgia, the Florida panhandle, and southeastern Louisiana. There are over 400 estimated occurrences, which potentially face threats from 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 atrorubens is endemic to the southeastern United States from Virginia and Kentucky south to central Georgia, the Florida panhandle, and southeastern Louisiana (FNA 2006, Weakley and the Southeastern Flora Team 2025). Range extent was estimated to be over 700,000 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 400 occurrences rangewide (GBIF 2025, iNaturalist 2025, RARECAT 2025, SEINet 2025).
Threat Impact Comments
Although rangewide 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. In southern Appalachians portion of this species' large range, it is highly threatened by land-use conversion and habitat fragmentation, and to a lesser extent by human disturbance (Southern Appalachian Species Viability Project 2002). However, their overall impact is likely negligible given the species' broad range and large number of occurrences.
Ecology & Habitat

Habitat

Helianthus atrorubens grows in dry soils of rocky, sandy, or clayey, open mixed woods and roadsides (FNA 2006, Weakley and the Southeastern Flora Team 2025).

Reproduction

This species flowers from late summer (late July) through fall (October) (FNA 2006, Weakley and the Southeastern Flora Team 2025).
Terrestrial Habitats
Forest EdgeWoodland - HardwoodWoodland - Mixed
Other Nations (1)
United StatesN5
ProvinceRankNative
AlabamaSNRYes
TennesseeSNRYes
LouisianaSNRYes
KentuckyS4Yes
South CarolinaS5Yes
VirginiaS5Yes
GeorgiaS4Yes
MississippiSNRYes
North CarolinaS5Yes
FloridaSNRYes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentUnknownUnknownUnknown
4 - Transportation & service corridorsUnknownUnknownUnknown
5 - Biological resource useUnknownUnknownUnknown
5.3 - Logging & wood harvestingUnknownUnknownUnknown
8 - Invasive & other problematic species, genes & diseasesUnknownUnknownUnknown
8.1 - Invasive non-native/alien species/diseasesUnknownUnknownUnknown
8.1.1 - Unspecified speciesUnknownUnknownUnknown

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Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)Yes
Roadless Areas (7)
Georgia (2)
AreaForestAcres
Kelly RidgeChattahoochee National Forest8,325
Pink KnobChattahoochee National Forest12,127
North Carolina (5)
AreaForestAcres
Catfish Lake NorthCroatan National Forest11,299
Chunky Gal (addition)Nantahala National Forest3,336
Overflow CreekNantahala National Forest3,379
Sam Knob (addition)Pisgah National Forest2,576
Tusquitee BaldNantahala National Forest13,670
References (8)
  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. Southern Appalachian Species Viability Project. 2002. A partnership between the U.S. Forest Service-Region 8, Natural Heritage Programs in the Southeast, NatureServe, and independent scientists to develop and review data on 1300+ regionally and locally rare species in the Southern Appalachian and Alabama region. Database (Access 97) provided to the U.S. Forest Service by NatureServe, Durham, North Carolina.
  7. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
  8. 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).