Leaflets three, let it be: How to recognize and avoid poison ivy

Alot of what I know about the natural world I learned from my grandfather. He was an old-time Pennsylvania woodsman who knew everything there was to know about the plants and animals that inhabit the Mon Valley woods. I wish I could recall a tenth of what he tried to teach me but at least the first thing he taught is burned into my brain: “Leaflets three — let it be!”