Urtica dioica, often called
common nettle or
stinging nettle (although not all plants of this
species sting), is a
herbaceous perennial flowering plant, native to
Europe,
Asia, northern
Africa, and western
North America, and is the best-known member of the nettle genus
Urtica. 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 when contacted by humans and other animals. The plant has a long history of use as a source of medicine, food, and fibre.