Poison oak is a plant related to poison ivy and poison sumac. It grows as a bush or vine. The leaves of poison oak usually consist of three leaflets. Each leaflet has several lobes and may resemble the leaf of the white oak tree. Small greenish or yellowish flowers and hairy, berrylike, light-colored fruits cluster at the point where the leafstalk joins the stem.
Two species of poison oak live in North America. Eastern poison oak grows from Long Island, New York, to northern Florida and west to West Virginia, Texas, and southern Kansas. Western poison oak grows from the Lower California peninsula in Mexico to British Columbia in Canada.
Poison oak has sap that can irritate the skin. All parts of the plants contain the sap. In case of contact with poison oak, wash the affected areas immediately and thoroughly with soap and water. If such symptoms as blisters or swelling are severe, see a physician.
