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Iris bracteata

S. Wats.

Siskiyou Iris

G3Vulnerable Found in 6 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.131405
Element CodePMIRI09020
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassMonocotyledoneae
OrderLiliales
FamilyIridaceae
GenusIris
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 Date2025-05-30
Change Date2025-05-30
Edition Date2025-05-30
Edition AuthorsFredricks, N.A. (1988), rev. N. Ventrella (2025)
Threat ImpactUnknown
Range Extent250-20,000 square km (about 100-8000 square miles)
Number of Occurrences21 - 80
Rank Reasons
Iris bracteata is a perennial forb occurring in shaded understories of coniferous and broadleaf upland forests of northern California and southern Oregon in the western United States. There are an estimated 39 occurrences of this species, though members of this group hybridize and form fertile offspring, making delineating populations within hybrid zones difficult. Potential threats to this species include serpentine soil mining, horticultural collection, invasive species, and fire suppression. In addition, trends and abundance of this species are not well documented, and monitoring populations is important to improving our understanding of the status of Iris bracteata.
Range Extent Comments
Iris bracteata occurs in the western United States, where it is endemic to northern California and southern Oregon (FNA 2002). The majority of populations are located in Del Norte County, California north through Josephine County, Oregon, though there are also scattered (and mostly historical) records from Siskiyou and Shasta counties (Serkanic and Sims 2018, CalFlora 2025, CNPS 2025). Range extent was estimated using herbarium specimens and photo-based observations documented between 1994 and 2025 (CCH2 2025, GBIF 2025, iNaturalist 2025, RARECAT 2025).
Occurrences Comments
By applying a 1 km separation distance to herbarium records and photo-based observations documented between 1994 and 2025, there are estimated to be 39 occurrences rangewide (CCH2 2025, GBIF 2025, iNaturalist 2025, RARECAT 2025). There are approximately eighteen occurrences estimated in Oregon (Dunkirk 2025). However, Iris bracteata hybridizes with other Pacific Coast irises (Iris series Californicae), producing fertile offspring, which can make delineating populations difficult.
Threat Impact Comments
Threats to Iris bracteata are not well known, but may include serpentine soil mining, horticultural collection, and invasive species (Serkanic and Sims 2018, Dunkirk 2025), though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this species. Fire suppression may also be a threat to I. bracteata (Serkanic and Sims 2018), as lack of fire over the last hundred years in the Klamath Mountains region of California has decreased the size and spatial characteristics of canopy gaps of forests, which has led to increased structural homogenization and decreased forest complexity (Skinner 1995).
Ecology & Habitat

Habitat

Iris bracteata occurs in shady forests, and is often associated with Ponderosa pine (FNA 2002). In California, this species is generally associated with yellow-pine forests (Jepson Flora Project 2025) and broadleaf upland forests (CNPS 2025). Iris bracteata tends to occupy drier forests of the eastern slope of the Cascade/Sierra divide where summers are long and hot (Young 1998).
Terrestrial Habitats
Forest/WoodlandForest - HardwoodForest - Conifer
Other Nations (1)
United StatesN3
ProvinceRankNative
CaliforniaS3Yes
OregonS2Yes
Threat Assessments
ThreatScopeSeverityTiming
3 - Energy production & miningUnknownUnknownUnknown
3.2 - Mining & quarryingUnknownUnknownUnknown
5 - Biological resource useUnknownUnknownUnknown
5.2 - Gathering terrestrial plantsUnknownUnknownUnknown
7 - Natural system modificationsUnknownUnknownUnknown
7.1 - Fire & fire suppressionUnknownUnknownUnknown
7.1.2 - Suppression in fire frequency/intensityUnknownUnknownUnknown
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)No
Roadless Areas (6)
California (5)
AreaForestAcres
KellySix Rivers National Forest5,195
Monkey CreekSix Rivers National Forest9,017
North Fork SmithSix Rivers National Forest37,898
SiskiyouKlamath National Forest54,039
Siskiyou BSix Rivers National Forest18,871
Oregon (1)
AreaForestAcres
South KalmiopsisSiskiyou National Forests104,477
References (17)
  1. CalFlora. 2025. Information on California plants for education, research and conservation. Berkeley, California: The CalFlora Database [web application]. Available: http://www.calflora.org/. (Accessed 2025).
  2. California Native Plant Society (CNPS), Rare Plant Program. 2025. Inventory of Rare and Endangered Plants of California, online edition, v9.5. Online. Available: https://www.rareplants.cnps.org (accessed 2025).
  3. CCH2 Portal. 2025. Consortium of California Herbaria. Online. Available: https//:www.cch2.org/portal/index.php (Accessed 2025).
  4. Center for Plant Conservation (CPC). 2025. CPC Pollinators of Rare Plants Database. Online. Available: https://saveplants.org/pollinator-search/ (accessed 2025).
  5. Dunkirk, N. 2025. Oregon state rank assessment for Siskiyou iris (<i>Iris bracteata</i>). Oregon Biodiversity Information Center. Institute for Natural Resources, Portland State University, Portland, OR.
  6. Flora of North America Editorial Committee (FNA). 2002a. Flora of North America north of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. Oxford Univ. Press, New York. xxvi + 723 pp.
  7. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  8. iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
  9. Jepson Flora Project (eds.) 2025. Jepson eFlora. Online. Available: https://ucjeps.berkeley.edu/eflora/ (accessed 2025).
  10. 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.
  11. Lenz, LW. 1959. Hybridization and speciation in the Pacific Coast irises. Aliso 4: 237-309.
  12. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  13. Ponte, J.P.E. 2018. Jeweled spider flies (<i>Eulonchus Tristis</i>) are important pollinators of <i>Iris Bracteata</i>, a rare Siskiyou Mountain endemic. M.S. thesis. Humboldt State University, Arcata, CA. 45 pp.
  14. Serkanic, S., and A. Sims. 2018. Plant Species Evaluation Form: Iris bracteata (S. Watson), Siskiyou iris. California Native Plant Society. Online. Available: <a href="https://rareplantfiles.cnps.org/scc/IrisBracteataSpProfileSCC20180627.pdf">rareplantfiles.cnps.org/scc/IrisBracteataSpProfileSCC20180627.pdf</a> (Accessed 2025).
  15. Skinner, C. N. 1995. Change in spatial characteristics of forest openings in the Klamath Mountains of northwestern California, USA. Landscape Ecology 10(4): 219-228.
  16. U.S. Geological Survey (USGS). 2024. Gap Analysis Project (GAP) Protected Areas Database of the United States (PAD-US) 4.0: U.S. Geological Survey data release. Online. Available: https://doi.org/10.5066/P96WBCHS (accessed 2025).
  17. Young, N.D. 1998. Pacific Coast Iris species delimitation using three species definitions: biological, phylogenetic and genealogical. Biological Journal of the Linnean Society 63(1): 99-120.