Stinging nettles (Urtica Dioica) are easily recognised and can also be unpopular as a weed; unfortunately it is often easily felt as the whole plant is covered in stinging hairs.
Stinging nettles produce formic acid which they hold in brittle hollow hairs. When you crush a plant, you break the hairs, causing the acid to burn your skin.
Nettles can be made into drinks such as beer, wine, champagne and tea. They are high in iron, vitamin C, a source of Calcium and Magnesium. Nettle soup is also popular. They are also an important wildlife plant for insects, birds, and butterflies, such as the small tortoiseshell and peacock that will use it as their food plant.