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Home/Species/ Serpentine Sunflower

Helianthus bolanderi

Gray

Serpentine Sunflower

G4Apparently Secure Found in 2 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
Least concernIUCN
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.157917
Element CodePDAST4N080
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderAsterales
FamilyAsteraceae
GenusHelianthus
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.
Taxonomic Comments
This record is for Helianthus bolanderi in the broad sense including Helianthus exilis, a serpentine restricted entity of California that is recognized as distinct by Schilling in the Flora of North America (2006c). Helianthus exilis and H. bolanderi are genetically indistinguishable and H. bolanderi also occurs on serpentine soils (Owens et al. 2016).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-02-06
Change Date1988-05-16
Edition Date2025-02-06
Edition AuthorsNordman, C. (2025).
Threat ImpactMedium
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
Serpentine Sunflower (Helianthus bolanderi) occurs in the western United States, only in California and southern Oregon. It is estimated that there are between 81 and 300 occurrences, and perhaps about 40000 individual plants. Residential development and urbanization is a threat. It has been documented in California in Yosemite National Park, on the BLM Payne Ranch, in Bidwell Park (City of Chico), and on the Klamath, Los Padres, Mendocino, Plumas, Shasta-Trinity, and Tahoe National Forests, USDA Forest Service Mokelumne Wilderness, Gray Lodge Wildlife Area, and in Oregon on BLM lands including the Cascade-Siskiyou National Monument and on the Siskiyou National Forest.
Range Extent Comments
Serpentine Sunflower (Helianthus bolanderi) occurs in the western United States, only in California and southern Oregon. Range extent was estimated using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1994 and 2025 (GBIF 2025, iNaturalist 2025, Keil 2020, NatureServe 2025, CCH2 2025).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2024, it is estimated that there are between 81 and 300 occurrences of Serpentine Sunflower (Helianthus bolanderi) rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, CCH2 2025).
Threat Impact Comments
Residential development and urbanization is a threat.
Ecology & Habitat

Habitat

This species occurs in grassy, usually disturbed areas, including gravelly streamsides, sometimes on serpentine at elevations less than 1800 meters, broadly ranging from 10 to 1400 meters (Keil 2020, Schilling in Flora of North America 2006c).

Reproduction

Flowers from June to October (Keil 2020).
Terrestrial Habitats
Grassland/herbaceous
Palustrine Habitats
Riparian
Other Nations (1)
United StatesN4
ProvinceRankNative
CaliforniaSNRYes
OregonS2Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)
1.1 - Housing & urban areasRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)

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Plant Characteristics
DurationANNUAL
Economic Value (Genus)Yes
Roadless Areas (2)
California (2)
AreaForestAcres
ChinquapinShasta-Trinity National Forest22,040
De La GuerraLos Padres National Forest5,418
References (8)
  1. CCH2 Portal. 2025. Consortium of California Herbaria. Online. Available: https//:www.cch2.org/portal/index.php (Accessed 2025).
  2. 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.
  3. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  4. iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
  5. 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.
  6. Keil, D.J. 2020. <i>Helianthus</i>, in Jepson Flora Project (eds.). Jepson eFlora, Revision 8. Online. Available: https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=466 (accessed 07 August 2023).
  7. NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  8. Owens, G.L., G.J. Baute, and L.H. Rieseberg. 2016. Revisiting a classic case of introgression: hybridization and gene flow in Californian sunflowers. Molecular Ecology 25(11):2630–2643.