Poisonwood is a member of the cashew family, which also includes poison ivy, poison sumac, poison oak and, perhaps surprisingly, mango. All parts of the tree contain a resin called urushiol, which can cause rashes and mucous membrane irritation in humans. It is so potent that people have even been affected by water dripping off poisonwood leaves, and by inhaling smoke from burning parts of the poisonwood. [Poisonwood: The Bad and the Ugly]
During last week’s trip to Key West and the Everglades I was reacquainted with the Poisonwood tree. Fortunately, it’s only found on Big Pines Key (about 20 miles north of Key West) and the southern most parts of the Everglades National Park. Thankfully you won’t encounter it during a hike on the Florida National Scenic Trail. The resin from this tree is extremely toxic when compared with its relatives poison oak – poison ivy – and poison sumac. If you need another reason to avoid moving to Florida, this is it.