Rhus diversiloba (syn. Toxicodendron diversilobum) Anacardiaceae
Poison Oak roos di-ver-si-LOW-ba
- Broadleaf deciduous shrub, erect, 3-7 ft (1-2 m) high, or a climbing vine, sometimes up to 50 ft (15 m). Leaves pinnately compound with 3 leaflets, each leaflet is rounded, obtuse, with a glossy upper surface, margin entire or irregularly toothed, may be highly colored (red and gold) in fall. Flowers small, inconspicuous, yellowish-green, in loose clusters (panicles). Fruit 5 mm diameter, white or cream colored, ribbed, in clusters, remain after leaf fall.
- All parts of the plant are toxic, an allergic contact dermatitis. About 70% of adults who contact poison oak or poison ivy (Toxicodendron radicans) will develop a rash in a delayed fashion from about 8 hr minimum to 2 weeks later. The rash is due to allergic reaction to urushiol resin on leaves or stems. Indirect contact via smoke or animals with the resin on their fur can also cause the rash to appear.
- Native to western parts of Washington, Oregon, and California.
- Oregon State Univ. campus: extreme western side of campus, beyond Hinsdale Wave Lab. on Jefferson Way.