Click to enlarge
More commonly known as Stinging nettle is painful when you drag your leg across it. I just did it yesterday in a garden with a mature plant I did not see. They are not dangerous; do not contain poison, they just seem to reach out and hurt your legs when you least expect it. In fact, the leaves are highly edible (tastes like spinach), and the roots are use in many beneficial drugs. Just Ouch !!