Toxicodendron diversilobum

Poison oak (synonymous with Rhus diversiloba) is noted for causing significant and long-lasting skin irritations (allergic dermatitis) in most humans who come into contact with the plant. It is native from British Columbia south to Baja California, from sea level to about 5000 feet in elevation, primarily in areas west of the Cascades and Sierras. It is typically found along the coast in scrubby areas or open woodland areas and further inland in valleys, foothill thickets, grassy hillsides, coniferous forests and along streams. This is a deciduous shrub (to 3-10 tall) or climbing vine (to 50 t... more »

Poison oak (synonymous with Rhus diversiloba) is noted for causing significant and long-lasting skin irritations (allergic dermatitis) in most humans who come into contact with the plant. It is native from British Columbia south to Baja California, from sea level to about 5000 feet in elevation, primarily in areas west of the Cascades and Sierras. It is typically found along the coast in scrubby areas or open woodland areas and further inland in valleys, foothill thickets, grassy hillsides, coniferous forests and along streams. This is a deciduous shrub (to 3-10 tall) or climbing vine (to 50 tall) that features trifoliate leaves with ovate to obovate oak-like leaflets. Leaves emerge with burgundy tinting in spring, mature to glossy green in summer and turn sometimes attractive shades of gold and red in fall. White flowers bloom in spring. Fertilized flowers on female plants give way to white to green-white spherical fruits in summer. This western form is sometimes commonly called Pacific poison oak. (less)