Pacific poison oak
Toxicodendron diversilobum
A variable shrub or climbing vine whose urushiol oil can cause allergic contact dermatitis. Green, red, or absent leaves do not provide a reliable measure of exposure risk.
- Family
- Anacardiaceae
- Regional status
- Native
- Habitat
- Woodland edges & chaparral
- Safety
- Contact hazard
A closer look.
Leaflets commonly occur in threes, but appearance and growth form are variable. UC IPM warns that detached and dried material can still cause dermatitis. Do not burn poison oak: smoke can expose people to hazardous material.
University of California Statewide IPM Program ↗
Compared with linked references on October 22, 2026. This is source verification, not independent expert review or an identification guarantee. Seasonal tags are approximate. Specimen maps show a selected historical subset.
Through the seasons
Seasonal appearance changes, but exposure risk persists even on leafless or dead plant material.
Knowledge has a context.
Historical accounts are presented as attributed records, not endorsed practices, medical advice, or permission to harvest.
No historical-use account is reviewed in this pilot. Documented cultural knowledge requires careful attribution and must not be translated into unsupervised handling instructions.
A record of where it was found.
A California woodland, scrub, and edge-habitat species. Historical specimen locations cannot establish absence or safety along a trail.
Woodland edges & chaparral
Northern California · Central California · Southern California
Historical collections are evidence of recorded locations, not a continuous range, current presence, abundance, native status, or confirmed identification. Unmapped places are not evidence of absence.
What this map includes
From the first 300 results returned by the stored GBIF query, 20 specimens met the coordinate and reuse filters; 280 were excluded. The query matched 948 records at retrieval. This subset is not random or exhaustive.
Records are labeled California, have coordinates, and lack GBIF geospatial-issue flags. We exclude known coordinate uncertainty above 25 km and use only CC0 or CC BY 4.0 records. 17 included records do not report coordinate uncertainty. A 0.25° cell is about 28 km north to south; it does not show an exact collecting site.
Matched taxon: Toxicodendron diversilobum ↗.
Inspect the stored query ↗ · Download the attributed snapshot ↓
University of California Statewide IPM Program ↗
Data publishers & selected records
Dataset citations apply to the contributing specimens. The snapshot retains record IDs, original ownership, and reuse licenses; coordinates are generalized to a quarter-degree grid.
- Herbarium of Taiwan Biodiversity Research Institute, TAIWAN (TAIE) ↗
Chang H, Chang H, Yu Y, Li H (2026). Herbarium of Taiwan Biodiversity Research Institute, TAIWAN (TAIE). Version 1.19. Taiwan Biodiversity Research Institute. Occurrence dataset https://doi.org/10.15468/4uvvfx accessed via GBIF.org on 2026-10-26.
http://creativecommons.org/licenses/by/4.0/legalcode · accessed October 26, 2026
- Tropicos MO Specimen Data ↗
Teisher J, Stimmel H (2026). Tropicos MO Specimen Data. Missouri Botanical Garden. Occurrence dataset https://doi.org/10.15468/hja69f accessed via GBIF.org on 2026-10-26.
http://creativecommons.org/licenses/by/4.0/legalcode · accessed October 26, 2026
- Miami University Turrell Herbarium - Vascular Plants ↗
W.S. Turrell Herbarium (MU) (2026). Miami University Turrell Herbarium - Vascular Plants. Occurrence dataset https://doi.org/10.15468/vzkvuf accessed via GBIF.org on 2026-10-26.
http://creativecommons.org/publicdomain/zero/1.0/legalcode · accessed October 26, 2026
- NMNH Extant Specimen Records (USNM, US) ↗
Orrell T, Informatics and Data Science Center - Digital Stewardship (2026). NMNH Extant Specimen Records (USNM, US). Version 1.113. National Museum of Natural History, Smithsonian Institution. Occurrence dataset https://doi.org/10.15468/hnhrg3 accessed via GBIF.org on 2026-10-26.
http://creativecommons.org/publicdomain/zero/1.0/legalcode · accessed October 26, 2026
- R. L. McGregor Herbarium Vascular Plants Collection ↗
Bentley A, Morse C (2026). R. L. McGregor Herbarium Vascular Plants Collection. University of Kansas Biodiversity Institute. Occurrence dataset https://doi.org/10.15468/htptzr accessed via GBIF.org on 2026-10-26.
http://creativecommons.org/licenses/by/4.0/legalcode · accessed October 26, 2026
- NEON Biorepository Terrestrial Plant Collection (Canopy Foliage) ↗
National Ecological Observatory Network (2026). NEON Biorepository Terrestrial Plant Collection (Canopy Foliage). Occurrence dataset https://doi.org/10.15468/km9xvj accessed via GBIF.org on 2026-10-26.
http://creativecommons.org/licenses/by/4.0/legalcode · accessed October 26, 2026
- STNF - Shasta-Trinity National Forest Herbarium ↗
USDA Forest Service (FS) (2026). STNF - Shasta-Trinity National Forest Herbarium. Occurrence dataset https://doi.org/10.15468/rkp6nr accessed via GBIF.org on 2026-10-26.
http://creativecommons.org/publicdomain/zero/1.0/legalcode · accessed October 26, 2026
- CAS Botany (BOT) ↗
Magnaghi E, Fong J (2026). CAS Botany (BOT). Version 157.669. California Academy of Sciences. Occurrence dataset https://doi.org/10.15468/7gudyo accessed via GBIF.org on 2026-10-26.
http://creativecommons.org/publicdomain/zero/1.0/legalcode · accessed October 26, 2026
View 20 included specimen records
- GBIF 6340371301 ↗ · 2026CAS Botany (BOT) · York, Dana; Shevock, Jim · License
- GBIF 6496887576 ↗ · 2024NEON Biorepository Terrestrial Plant Collection (Canopy Foliage) · Alistair Hart-Alesch (ORCID 0000-0003-1699-6511) · License
- GBIF 6496887451 ↗ · 2024NEON Biorepository Terrestrial Plant Collection (Canopy Foliage) · Daniel Burgener (0009-0006-2604-8514) · License
- GBIF 6496888305 ↗ · 2024NEON Biorepository Terrestrial Plant Collection (Canopy Foliage) · Daniel Burgener (0009-0006-2604-8514) · License
- GBIF 4947057595 ↗ · 2022CAS Botany (BOT) · White, Scott D.; Myers, Steve · License
- GBIF 6491443616 ↗ · 2022Miami University Turrell Herbarium - Vascular Plants · Vincent, M.A.; Vincent, M.W. · License
- GBIF 4418974323 ↗ · 2020CAS Botany (BOT) · House, Nina · License
- GBIF 4851122206 ↗ · 2014STNF - Shasta-Trinity National Forest Herbarium · R.W. Tate; J. Inkster · License
- GBIF 4851122207 ↗ · 2014STNF - Shasta-Trinity National Forest Herbarium · R.W. Tate; J. Inkster · License
- GBIF 1321859568 ↗ · 2014NMNH Extant Specimen Records (USNM, US) · J. Wen · License
- GBIF 4432787330 ↗ · 2013CAS Botany (BOT) · Crowe, R.; Hinman, E.; Pollak, T.; Woods, J. · License
- GBIF 6446355309 ↗ · 2010CAS Botany (BOT) · Swinney, R. G. · License
- GBIF 233102315 ↗ · 2008R. L. McGregor Herbarium Vascular Plants Collection · Caleb A. Morse · License
- GBIF 1426273508 ↗ · 2007CAS Botany (BOT) · De Groot, Sarah J. · License
- GBIF 3866727525 ↗ · 2006Herbarium of Taiwan Biodiversity Research Institute, TAIWAN (TAIE) · Tsai-Wen Hsu (許再文) · License
- GBIF 3866727530 ↗ · 2006Herbarium of Taiwan Biodiversity Research Institute, TAIWAN (TAIE) · Tsai-Wen Hsu (許再文) · License
- GBIF 6561374013 ↗ · 2004Tropicos MO Specimen Data · Oscar F. Clarke · Missouri Botanical Garden · License
- GBIF 6561590831 ↗ · 2003Tropicos MO Specimen Data · Mark A. Elvin · Missouri Botanical Garden · License
- GBIF 6341260432 ↗ · 2002NMNH Extant Specimen Records (USNM, US) · J. Wen · License
- GBIF 1426273585 ↗ · 1999CAS Botany (BOT) · Daniel, T. F. · License
Darker = more included records, not abundance
Boundary: US Census Bureau TIGERweb ↗ · locations generalized to 0.25° cells
Trace the record.
References are attached to specific parts of this record. A citation is a route to evidence; it is not a claim that every field has completed review.
- 01Poison Oak — Pest Notes ↗
University of California Statewide IPM Program
Supports: Dermatitis risk, morphology, and safe avoidance.
- 02GBIF occurrence records & citation guidance ↗
GBIF Secretariat and contributing data publishers
Supports: Specimen occurrence snapshot. Each contributing dataset, DOI where available, record identifier, and license is retained in the downloadable map data.
- 03TIGERweb — States and Counties ↗
US Census Bureau
Supports: Generalized California state outline only; does not imply a species distribution.