Toxicodendron diversilobum

Poison Oak. Western poison oak. Toxicodendron diversilobum (T. G.) Greene, Anacardiaceae. Similar to poison ivy in that it has three leaflets, grows as a shrub or vine and produces dermatitis in man. Interbreeds with poison ivy. Habit. Western North America from southern British Columbia to northern Baja California. Constit. Poisons presumably closely related if not identical to those in poison ivy. 

Toxicodendron diversilobum Trichoscypha arborea Dracontomelon edule Spondias mombin Tapirira guanensis... 

Main constituent of the allergenic oil of poison ivy Toxicodendron radicans)y poison oak (T. diversilobum) Asiatic lacquer tree (T. verniciferum D.C.) and other plants of the genera Toxicodendron and Anacardiaceae. A mixture of several compounds which are derivatives of catechol Uses in Japanese lacquer... 

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