| Stinging nettle | ||||||||||||||
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 Urtica dioica subsp. dioica | ||||||||||||||
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| Urtica dioica L. | ||||||||||||||
The stinging nettle (Urtica dioica) is a herbaceous flowering plant native to Europe, Asia, northern Africa, and North America, and is the best known member of the nettle genus Urtica.
The taxonomy of stinging nettles in the genus Urtica has been confused, and older sources are likely to use a variety of systematic names for these plants. Formerly, more species were recognised than are now accepted. However, there are at least five clear subspecies, some formerly classified as separate species:
- U. dioica subsp. dioica (European stinging nettle). Europe, Asia, northern Africa.
- U. dioica subsp. afghanica. Southwestern and central Asia.
- U. dioica subsp. gansuensis. Eastern Asia (China).
- U. dioica subsp. gracilis (Ait.) Selander (American stinging nettle). North America.
- U. dioica subsp. holosericea (Nutt.) Thorne (hairy nettle). North America.
Other species names formerly accepted as distinct by some authors but now regarded as synonyms of U. dioica include U. breweri, U. californica, U. cardiophylla, U. lyalli, U. major, U. procera, U. serra, U. strigosissima, U. trachycarpa, and U. viridis. Other vernacular names include tall nettle, slender nettle, California nettle, jaggy nettle, burning weed, and bull nettle (a name shared by Cnidoscolus texanus and Solanum carolinense).
Stinging nettles are an herbaceous perennial, growing to 1-2 m tall in the summer and dying down to the ground in winter. It has very distinctively yellow, widely spreading roots. The soft green leaves are 3-15 cm long, with a strongly serrated margin, a cordate base and an acuminate tip. Both the leaves and the stems are covered with brittle, hollow, silky hairs that were formerly thought to contain formic acid as a defence against grazing animals. Recent research has revealed the cause of the sting to be from three chemicals - a histamine that irritates the skin, acetylcholine which causes a burning sensation and serotonin, that encourages the other two chemicals (Elliott 1997). Bare skin brushing up against a stinging nettle plant tends to break the delicate defensive hairs and release the trio of chemicals, usually resulting in a temporary and painful skin rash similar to poison ivy, though the nettle's rash and duration are much weaker. It is possible to evade the sting by touching the middle of the leaf or by stroking in the same direction as the hairs.
Stinging nettles are abundant in northern Europe and much of Asia, usually found in the countryside. It is less gregarious in southern Europe and north Africa, where it is restricted by its need for moist soil. In North America it is widely distributed in Canada and the United States, where it is found in every province and state except for Hawaii and South CarolinaTemplate:Fact, and also can be found in northernmost Mexico. In North America the stinging nettle is far less common than in northern Europe. The European subspecies has been introduced into North America as well as South America.
In the UK stinging nettles have a strong association with human habitation and buildings. The presence of nettles may indicate that a building has been long abandoned. Human and animal waste may be responsible for elevated levels of phosphate in the soil, providing an ideal environment for stinging nettles. This seems particularly evident in Scotland where the sites of crofts razed to the ground during the Highland Clearances can still be identified.
Uses
Stinging nettle has many uses. It is used by many different cultures for a wide variety of purposes in herbal medicine. Cooking, crushing or chopping disables the stinging hairs. Stinging nettle leaves are tasty and high in nutrients. The young leaves are edible and make a very good pot-herb. The leaves are also dried and may be then be used to make a tisane, as can also be done with the nettle's flowers.
Nettle stems contain a bast fibre which has been traditionally used for the same purposes as linen, and is produced by a similar retting process.
Home remedies
Several folk remedies exist for the sting, with disputed effectiveness:
- Juice from the crushed leaf of dock (Rumex spp.), which commonly grows in association with nettles, rubbed into the area helps.
- Both species of Jewelweed (Impatiens capensis and Impatiens pallida) can and have been used as preventatives and palliatives for Stinging Nettle rash. To do so, one can take the whole plant, crush it into a ball, and rub it onto the exposed area, or one can crush some jewelweed stems in a container, and then use a cotton ball to soak up the juice. The anti-inflammatory/fungicidal chemical in this plant is 2-methoxy-1,4-naphthoquinone.[1]
- Rubbing the underside of a fern leaf (which contains its spore pods or sori) on the afflicted area.
- Urinating on the affected area, as the ammoniac content of urine helps counteract the sting (Thiselton-Dyer 1889).
- Immediately rubbing mud on the affected area and allow it to dry before brushing it clean.
- Even quickly washing the affected area can help.
- A simple piece of ice can help relieve itchiness
Influence on language and culture
In England the stinging nettle is the only common stinging plant, and has found a place in several figures of speech in the English language. To "nettle" someone is to annoy them. Shakespeare's Hotspur urges that "out of this nettle, danger, we grasp this flower, safety" (Henry IV, part 1, Act II Scene 3). The common figure of speech "to grasp the nettle" probably originated as a condensation of this quotation. It means to face up to or take on a problem that has been ignored or deferred. The metaphor refers to the fact that if a nettle leaf is grasped firmly rather than brushed against, it does not sting so readily, because the hairs are crushed down flat and do not penetrate the skin so easily. However the sting of nettles has been recommended to relieve the pain of rheumatism as the effects of the sting can last up to twelve hours. The stinging feeling becomes a warm feeling on the area treated so helping the pain of the rheumatism to subside.
References
External links
- Plants for a Future database entry for Urtica dioica; comprehensive account with a long list of uses
- Germplasm Resources Information Network: Urtica dioica
- Flora of China: Urtica dioica
- Contact-poisonous plants of the world
- Elliott, C. (1997). Rash Encounters. Horticulture 94: 30.
- Schofield, Janice J. (1998). Nettles ISBN 0-585-10500-6
- Thiselton-Dyer, T. F., (1889). [http://www.dominiopublico
.gov.br/download/texto/gu010118.pdf The Folk-Lore of Plants].
- Glawe, G. A. (2006). Sex ratio variation and sex determination in Urtica diocia. ISBN 90-6464-026-2