Flowering nettles, Wylam, Northumberland.
Urtica dioica, often known as common nettle, stinging nettle (although not all plants of this species sting) or nettle leaf, or just a nettle or stinger, is a herbaceous perennial flowering plant in the family Urticaceae. Originally native to Europe, much of temperate Asia and western North Africa, it is now found worldwide, including New Zealand and North America. The species is divided into six subspecies, five of which have many hollow stinging hairs called trichomes on the leaves and stems, which act like hypodermic needles, injecting histamine and other chemicals that produce a stinging sensation upon contact (“contact urticaria”, a form of contact dermatitis). The plant has a long history of use as a source for traditional medicine, food, tea, and textile raw material in ancient societies such as the Saxons.