Hippomane mancinella
Among the most poisonous trees in the world, and one to know on sight. The manchineel grows along Caribbean beaches, a handsome shade tree bearing small green fruit like little apples — the manzanilla de la muerte, the little apple of death. Every part is toxic. The milky sap blisters skin, the fruit is dangerous to eat, and sheltering beneath it in the rain can cause burns. On Grenada's beaches, suspect trees are often marked with red paint. Admire it, learn it, and give it a wide berth.