There's a plant I've been pulling out of my back yard. It grows to be about two and a half feet tall. The stem is green with bits of red. The leaves are ragged edged, like chyrsanthemum leaves. The flowers are yellow and very small. When I touch it, I itch like Hell, if I don't wear gloves.
It seems to be the juice from the plant that is making me itch.
I've just spent a lot of time and effort pulling that stuff out of my yard. I'd like to know what I've been trying to eradicate.