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Erigeron oreganus

Gray

Oregon Fleabane

G3Vulnerable Found in 3 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.143503
Element CodePDAST3M2W0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderAsterales
FamilyAsteraceae
GenusErigeron
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 Date2025-02-25
Change Date1994-02-08
Edition Date2025-02-25
Edition AuthorsGries, D. (1997), rev. C. Nordman (2025).
Threat ImpactLow
Range Extent5000-20,000 square km (about 2000-8000 square miles)
Number of Occurrences6 - 20
Rank Reasons
Erigeron oreganus occurs in western North America, in the Pacific Northwest of the United States. It is endemic to the Columbia River Gorge and some nearby areas and is only known from Skamania and Wahkiakum counties in southwestern Washington and Hood River and Multnomah counties in northwestern Oregon, it is also reported from Clackimas County, in northwestern Oregon. It is estimated there are about 17 occurrences. It is protected on Columbia River Gorge National Scenic Area, Gifford Pinchot National Forest, Mount Hood National Forest, and on state parks in Oregon and Washington. Threats include recreational rock climbing, herbicide applications (such as along roadsides), and habitat loss from timber harvest and mining. Threats are limited and plants are generally inaccessible, along cliffs.
Range Extent Comments
Erigeron oreganus occurs in western North America, in the Pacific Northwest of the United States. It is endemic to the Columbia River Gorge and some nearby areas and is only known from Skamania and Wahkiakum counties in southwestern Washington and Hood River and Multnomah counties in northwestern Oregon, it is also reported from Clackimas County, in northwestern Oregon. Range extent was estimated to be about 5400 square kilometers, using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1994 and 2025 (FNA 2006, GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2024, SEINet 2025, WNHP 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 2025, it is estimated that there are about 17 occurrences of Erigeron oreganus rangewide (RARECAT 2024, GBIF 2025, iNaturalist 2025, NatureServe 2025, SEINet 2025).
Threat Impact Comments
Disturbance to the plants from recreational rock climbing is a threat to some of the occurrences, otherwise threats are limited and plants are generally inaccessible, along cliffs, but it is also vulnerable to herbicide application (such as along roadsides), and habitat loss from timber harvest and mining (NatureServe 2025, WNHP 2025).
Ecology & Habitat

Diagnostic Characteristics

"Erigeron basalticus has more deeply three-lobed leaves on the stem and lacks a basal cluster of leaves. Erigeron leibergii has entire, prominently three-veined basal leaves and straight pappus bristles" (WNHP 2025).

Habitat

This species occurs on shady, moist ledges and cliffs (FNA 2006), in "wet environments on basalt outcroppings and moist and shady basalt cliffs and ledges, often beneath overhangs or near waterfalls, at elevations of 15-520 m (50-1700 ft). The ecological system is North Pacific Montane Massive Bedrock, Cliff and Talus (Rocchio and Crawford 2015). Common associated plants include cliff beardtongue (Penstemon rupicola), Scotch bellflower (Campanula rotundifolia), maidenhair fern (Adiantum aleuticum), Oregon stonecrop (Sedum oreganum), irregular polypody fern (Polypodium amorphum), and Pacific ninebark (Physocarpus capitatus) (WNHP 2025)

Reproduction

Flowering May to August or September, the seed has pappus of bristles, which can promote seed dispersal by mammals (FNA 2006, WNHP 2025).
Terrestrial Habitats
Cliff
Palustrine Habitats
Riparian
Other Nations (1)
United StatesN3
ProvinceRankNative
OregonS2Yes
WashingtonS2Yes
Threat Assessments
ThreatScopeSeverityTiming
6 - Human intrusions & disturbanceRestricted - smallModerate or 11-30% pop. declineHigh (continuing)
6.1 - Recreational activitiesRestricted - smallModerate or 11-30% pop. declineHigh (continuing)

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Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (3)
Oregon (2)
AreaForestAcres
EagleMt. Hood National Forest16,841
LarchMt. Hood National Forest12,961
Washington (1)
AreaForestAcres
Bear CreekGifford Pinchot National Forest7,980
References (8)
  1. Flora of North America Editorial Committee (FNA). 2006b. Flora of North America north of Mexico. Vol. 20. Magnoliophyta: Asteridae, part 7: Asteraceae, part 2. Oxford Univ. Press, New York. xxii + 666 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. NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  6. Rocchio, F.J., and R.C. Crawford. 2015. Ecological systems of Washington State. A guide to identification. Natural Heritage Report 2015-04. Washington Natural Heritage Program, WA Department of Natural Resources, Olympia, WA. 384 pp.
  7. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
  8. Washington Natural Heritage Program (WNHP). 2025. Online Field Guide to the Rare Plants of Washington. Online. Available: https://fieldguide.mt.gov/wa (accessed 2025).