Dermatitis resulting from contact with a poison oak plant.
2.
Climbing plant common in eastern and central United States with ternate leaves and greenish flowers followed by white berries; yields an irritating oil that causes a rash on contact. Synonyms:markweed, poison ivy, poison mercury, Rhus radicans, Toxicodendron radicans.
... poison ivy, which seemed here to deserve its other name of poison oak, for it was more like a tree than a vine, flinging its knotted branches from shore to shore, and thrusting its pallid, venomous blossoms into our faces. Walter was especially susceptible to the influence of this poison, so we put him in the ... — Days Off - And Other Digressions • Henry Van Dyke
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