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Home/Species/ Rosy Owl's-clover

Orthocarpus bracteosus

Benth.

Rosy Owl's-clover

G3Vulnerable Found in 4 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.131593
Element CodePDSCR1H030
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderScrophulariales
FamilyOrobanchaceae
GenusOrthocarpus
Other Common Names
Orthocarpe à épi feuillu (FR) rosy owl's-clover (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 Date2025-01-27
Change Date2025-01-27
Edition Date2025-01-27
Edition AuthorsSoteropoulos (2025)
Threat ImpactUnknown
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences21 - 80
Rank Reasons
Orthocarpus bracteosus is an annual hemiparasitic herb in seasonally wet meadows, vernal pools, and coastal prairies occurring in western North America from southwestern British Columbia, Canada south in the United States to northeastern California. There are an estimated 31 occurrences rangewide that face threats from development, conversion to agriculture, livestock grazing and habitat alteration from nutrient addition, maintenance activities along roadsides and near a radio tower, recreational activities, hydrological alteration and succession, and invasive species. Monitoring of populations should be conducted to improve our understanding of reproduction, plant abundance, threats, and trends, as well as continuing conservation measures to protect the taxon.
Range Extent Comments
Orthocarpus bracteosus occurs in western North America from southwestern British Columbia, Canada south in the United States to northeastern California (COSEWIC 2004, FNA 2019, Jepson 2025). It is introduced in the eastern United States in New York and Maryland (COSEWIC 2004, Weakley and the Southeastern Flora Team 2024). Native range extent was estimated to be approximately 132,000 square kilometers using herbarium specimens and NatureServe Network occurrence data documented between 1984 and 2025 (GBIF 2025, NatureServe 2025, SEINet 2025).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens and NatureServe Network occurrence data documented between 1984 and 2025, it is estimated that there are 31 occurrences rangewide (GBIF 2025, NatureServe 2025, SEINet 2025).
Threat Impact Comments
Although threats are not widely documented, this species is threatened by habitat fragmentation and declining habitat quality from development, conversion to agriculture, livestock grazing and habitat alteration from nutrient addition, possible oil spills from busy shipping lanes, maintenance activities along roadsides and near a radio tower, recreational activities, hydrological alteration and succession, invasive species, and other threats in some places (COSEWIC 2004, NatureServe 2025), though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this species.
Ecology & Habitat

Habitat

Orthocarpus bracteosus grows in seasonally wet meadows, vernal pools, and coastal prairies at elevations ranging from 10 to 2,000 meters (COSEWIC 2004, FNA 2019).
Terrestrial Habitats
Grassland/herbaceous
Palustrine Habitats
TEMPORARY POOLHERBACEOUS WETLAND
Other Nations (2)
CanadaN1
ProvinceRankNative
British ColumbiaS1Yes
United StatesN3
ProvinceRankNative
CaliforniaS1Yes
OregonSNRYes
WashingtonS2Yes
MarylandSNANo
New YorkSNANo
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentUnknownExtreme or 71-100% pop. declineHigh (continuing)
2 - Agriculture & aquacultureUnknownSerious - moderateHigh (continuing)
2.3 - Livestock farming & ranchingUnknownSerious - moderateHigh (continuing)
4 - Transportation & service corridorsUnknownModerate or 11-30% pop. declineHigh (continuing)
4.1 - Roads & railroadsUnknownModerate or 11-30% pop. declineHigh (continuing)
4.2 - Utility & service linesSmall (1-10%)UnknownHigh (continuing)
4.3 - Shipping lanesSmall (1-10%)UnknownHigh (continuing)
6 - Human intrusions & disturbanceUnknownUnknownHigh (continuing)
6.1 - Recreational activitiesUnknownUnknownHigh (continuing)
7 - Natural system modificationsUnknownUnknownHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesUnknownUnknownHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesUnknownUnknownHigh (continuing)
8.1.1 - Unspecified speciesUnknownUnknownHigh (continuing)

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Plant Characteristics
DurationANNUAL
Economic Value (Genus)No
Roadless Areas (4)
California (2)
AreaForestAcres
Crane Mtn.Modoc National Forest1,269
Mt. VidaModoc National Forest7,771
Oregon (2)
AreaForestAcres
Crane MountainFremont National Forest23,096
South KalmiopsisSiskiyou National Forests104,477
References (9)
  1. COSEWIC 2004. COSEWIC assessment and status report on the rosy owl-clover <i>Orthocarpus bracteosus</i> in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 18 pp. Online. Available: https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/cosewic-assessments-status-reports/rosy-owl-clover.html (accessed 2025).
  2. Flora of North America Editorial Committee (FNA). 2019. Flora of North America north of Mexico. Vol. 17: Magnoliophyta: Tetrachondraceae to Orobanchaceae. Oxford Univ. Press, New York. xxiv + 737 pp.
  3. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  4. Jepson Flora Project (eds.) 2025. Jepson eFlora. Online. Available: https://ucjeps.berkeley.edu/eflora/ (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. Munz, P.A., with D.D. Keck. 1959. A California flora. Univ. California Press, Berkeley. 1681 pp.
  7. NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  8. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
  9. Weakley, A.S., and Southeastern Flora Team. 2024. Flora of the southeastern United States. Edition of March 4, 2024. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. 2203 pp.