Nettles

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Nettles
Great nettle (Urtica dioica)

Great nettle ( Urtica dioica )

Systematics
Rosids
Eurosiden I
Order : Rose-like (rosales)
Family : Nettle family (Urticaceae)
Tribe : Urticeae
Genre : Nettles
Scientific name
Urtica
L.

The nettles ( Urtica ) form a genus of plants in the nettle family (Urticaceae). They occur almost worldwide. In Germany you can find the large nettle and the small nettle and, more rarely, the reed nettle and the pill nettle .

description

Illustration of the big nettle in Otto Wilhelm Thomé : Flora of Germany, Austria and Switzerland , 1885 in Gera.

Vegetative characteristics

Nettle species grow as annual or perennial herbaceous plants , rarely also as subshrubs . The species represented in Central Europe reach heights of growth of ten to 300 centimeters, depending on the species, location and nutrient situation. The perennial species form rhizomes as organs of expansion and persistence. The green parts of the plant are covered with stinging and bristle hairs. Their often square stems are branched or unbranched, upright, ascending or spreading.

Most cross-against-constantly arranged on the stem axis leaves are stalked. The leaf blades are elliptical, lanceolate, egg-shaped or circular and usually have three to five (up to seven) leaf veins . The leaf margin is usually serrated to more or less roughly serrated. The often durable stipules are free or fused together. The cystoliths are rounded to more or less elongated.

Stinging hairs

Stinging hairs on the petiole of a nettle, the heads can be guessed
Stinging hairs (large) and normal hair (small) on one sheet
Wheals after skin contact with nettles

The nettles are known and unpopular because of the painful wheals (swellings) that appear on the skin after touching the stinging hairs . Depending on the species, the severity of the consequences varies; for example, the liquid in the small nettle ( Urtica urens ) is much more painful than that of the large nettle ( Urtica dioica ).

These stinging hairs act as a protective mechanism against predators and are mainly present on the upper side of the leaf. They are long, single-celled tubes whose walls in the upper part are hard and brittle like glass due to embedded silica . The lower, more flexible end is heavily swollen, filled with fuel and sunk into a cell cup, the tip consists of a sideways-facing head, under which there is a kind of predetermined breaking point due to the very thin wall here .

The head may already with a light touch cancel, leaving an oblique, sharp breaking point similar to a medical syringes cannula . Upon contact, the hair sticks into the victim's skin, its formic acid-containing content squirts into the wound with pressure and immediately causes a brief, burning pain and then the aforementioned wheals associated with burning or itching.

Other active ingredients in the fuel are serotonin , histamine , acetylcholine and sodium formate . Just 100 nanograms of this fuel liquid are sufficient to achieve the known effect. Histamine dilates the blood capillaries and can cause reactions that are similar to allergic reactions (these are caused, among other things, by the release of the body's own histamine). Acetylcholine is also the transmitter substance of many nerve endings and is responsible for the burning pain. Since almost all stinging hairs are directed upwards, stinging nettles can be touched relatively safely by stroking them from bottom to top.

Even without the stinging hairs penetrating, skin contact with the burning liquid alone can have consequences: Fresh stinging nettle cut does not cause any pain when it comes into contact with the skin (e.g. when mowing the lawn) because broken stinging hairs cannot sting the skin and contain little poison. The brittle stinging hairs break as soon as the mower blade rotates and the fuel flows out freely. Upon wetting sensitive skin layers with liquid fuel (ankle and clamping range) a late pain response occurs because the liquid fuel to contact nerves loose upper skin ( epidermis ) by pores into the underlying corium ( dermis penetrating). There it only reaches free nerve endings ( nociceptors ) after hours . On the other hand, skin pricks that are more brittle, unbroken stinging hairs hurt in a fraction of a second. The relatively long poison contact time is directly proportional to the later burn intensity. The poison that has penetrated the dermis is only slowly broken down with sharp pain and swelling, and the epidermis, which has been burned over a large area, is replaced by a new one.

The nettle has given its name to a skin reaction, hives or urticaria. Just like nettle irritation, it causes itchy wheals and histamine is released from mast cells in the skin. However, the causes can be very different.

Male inflorescence of a great nettle just before opening
Flower diagrams of Urtica :
A male, B female flower
Detail of a partial inflorescence: close-up of a male flower, the bloom in the center of the picture is already open, but the stamens are still taut

Generative characteristics

Depending on the species, nettles are single- sexed ( monoecious ) or dioecious ( dioecious ). In the leaf axils in branched, are rispigen , ährigen , traubigen or capitate total inflorescences many zymöse part inflorescences together with each many flowers. The relatively small, inconspicuous, always unisexual flowers are two to six, but mostly four to five-fold.

The unisexual flowers are somewhat reduced. There are (two to) four (to five) bracts . The male flowers usually contain (two to) four (to five) stamens . The female flowers contain an ovary , which lies in the center of the flower and is formed from only one carpel .

Nettle species are wind pollinated. When the bracts of the male flowers open, their stamens pop out; a cloud of pollen is thrown into the air like an explosion . The wind then transfers the pollen to the female flowers.

The sitting nuts , loosely encased in the durable inner bloom cladding leaves, are straight, laterally flattened, egg-shaped or deltoid. The upright seeds contain little endosperm and two fleshy, almost circular cotyledons ( cotyledons ). They are spread by wind and animals.

The basic chromosome number is x = 12 or 13.

Some similar species

The species of the genus of nettles unrelated Taubnesseln ( Lamium ) see the nettles in growth and leaf shape is very similar, but do not have stinging hairs and much larger and more conspicuous flowers. The similarly similar leaves of the nettle-leaved bellflower ( Campanula trachelium ), on the other hand, are alternate.

Habitat for butterflies

Little fox caterpillar on nettle

For the caterpillars of around 50 species of butterflies , certain nettle species are a forage plant.

The butterfly species admiral , peacock butterfly , small fox (also known as nettle butterfly ), silver- gray nettle- humped owl , dark-gray nettle- humped owl , nettle- horned owl ( Hypena obesalis ) and the map are even dependent on the nettle, other plants do not come for these species into consideration ( monophagy ). Nevertheless, these butterfly species hardly seem to compete with each other, as they either prefer a different stinging nettle species or are relatively rare.

  • The caterpillars of the little fox can be found in dry and sunny places
  • The peacock butterfly also likes it sunny, but still humid and therefore prefers places near bodies of water.

Both species also need larger stocks of nettles.

  • The admiral, on the other hand, is satisfied with just a few plants and prefers rather poor nettles.
  • The map selects the most shady places where the nettle grows, the often large and dense stands in the alluvial forests that accompany the river and stream.

Traces of individual insects can be found on almost every nettle. They must have developed a strategy with which they deal with the stinging hair. They eat their way around the hair and prefer the paths along the leaf veins and the leaf edges, as there are no stinging hairs there. Advantageous for the insects: The poison does not penetrate from the tip if the hair is pecked at the root.

Occurrence

The genus Urtica is distributed almost worldwide, only in the Antarctic there are no species. Of the approximately 30 Urtica species, 14 are found in China. They mainly thrive in the temperate areas of the northern and southern hemispheres. But there are also species in the mountains of the tropics.

There are four species of nettles in German-speaking countries: The best known are the dioecious large nettle ( Urtica dioica ) and the single-domed small nettle ( Urtica urens ); In addition, there are the reed nettle ( Urtica kioviensis ) and the pill nettle ( Urtica pilulifera ), which was introduced from the Mediterranean region , whose occasional occurrence in Central Europe can be traced back to the flight from herb gardens, where it was cultivated for its slimy seeds.

Some species are very undemanding and therefore colonize a wide range of habitats.

Pointer function

A strong stinging nettle growth is generally regarded as an indicator of a nitrogen-rich soil and often develops as a ruderal plant on previously populated areas. A large number of nettles in an area therefore allows conclusions to be drawn about the nature of the soil without chemical investigations.

Systematics

The genus Urtica was established by Carl von Linné in Species Plantarum in 1753 . The diagnosis in Genera Plantarum also belongs to the Protolog . The generic name Urtica is derived from the Latin word urere for burn.

Flowering Urtica atrovirens
Siberian hemp nettle ( Urtica cannabina ), blooming
Tailed nettle ( Urtica membranacea ), blooming
Pill nettle ( Urtica pilulifera )
Stem, opposite, stalked leaves and stipules of Urtica thunbergiana
Ongaonga ( Urtica ferox )

The genus nettles ( Urtica ) contains about 45 species:

Species found in Europe (including the Canary Islands)

  • Urtica atrovirens Req. ex Loisel. , Home: Western Mediterranean.
  • Mallorca nettle ( Urtica bianorii ( bone ) Paiva ), is endemic to Mallorca .
  • Siberian hemp nettle ( Urtica cannabina L. ); Homeland: Southern Russia, Central Asia and Northern Asia.
  • Great nettle ( Urtica dioica L. ), occurs in Eurasia, North Africa and North America and is naturalized in Polynesia and South America.
  • Reed nettle ( Urtica kioviensis Rogow. ), Occurs in Central and Eastern Europe.
  • Tailed nettle ( Urtica membranacea Poir. Ex Savigny ), occurs in Europe in the Mediterranean region, in Western Europe and on the Azores.
  • Mulberry-leaved nettle ( Urtica morifolia Poir. ), Occurs in Madeira, the Canary Islands and naturalized in the Azores.
  • Pill nettle ( Urtica pilulifera L. ), occurs in Europe, Asia and North Africa.
  • Urtica pubescens Ledeb. , occurs in Russia.
  • Urtica rupestris cast. , occurs only in Sicily.
  • Urtica sondenii ( Simmons ) Avrorin ex Geltman , occurs in Northern and Eastern Europe.
  • Urtica stachyoides Webb & Benth.
  • Small nettle ( Urtica urens L. ), occurs in Eurasia, North Africa, North America and Greenland.

Other species not found in Europe

use

Most of the following aspects relate to the great nettle ( Urtica dioica ), which, among other things, serves as a medicinal and useful plant.

Food

Nettle spinach with boiled potatoes and egg

Some species use the green plant parts, the underground plant parts and the seeds. The young nettle shoots are valued as spring vegetables because of their high content of flavonoids , minerals such as magnesium , calcium and silicon , vitamins A and C (about twice as much vitamin C as oranges), iron, but also because of their high protein content. The nettle contains about 30 percent protein in the dry matter. The taste is described as "similar to spinach, but more aromatic" and as delicately sour.

The use of wild nettles as food ( wild herbs ), especially of fresh shoots in spring, has been attested since antiquity from northern and western Europe as well as the indigenous population of Canada. It was used as wild vegetables (in Scotland kail ), soup or tea. Special uses were, for example, the addition in cooking to get tender meat, or as a substitute for rennet for making cheese.

The seeds of the nettle are suitable for roasted consumption or can be further processed into nettle seed oil.

The unpleasant effect of nettle hair can be counteracted when used raw for salads, for example, by wrapping the young above-ground parts of the plant in a cloth and wringing them strongly, for example cutting them very finely with a chopping knife , rolling them well with a rolling pin or giving them a powerful shower . Cooking and brief blanching for nettle spinach and soup also make the nettle hair harmless. They also lose their irritating effect when the above-ground parts of the plant are dried for tea preparation .

Fiber recovery

Substances made from nettles already existed thousands of years ago, of which there are examples from many regions, in the earlier centuries mainly from China. In the last third of the 19th century, interest in the native fiber plant revived due to a cotton shortage. Around 1900 nettle was considered the " linen of the poor people". During the Second World War, nettle cloth was increasingly used in Germany for army clothing. The fibers can be exposed through microbiological processes.

The fiber content of the cellulose fibers in wild nettles reaches an average of around 5 percent and has been increased to 16 percent in lines optimized for fiber production. In previous cultivation trials, the crude fiber yield is a maximum of around one ton per hectare of cultivation area, but mostly less.

Dye plant

For a long time the nettle was one of the coloring herbs . Wool can be dyed wax yellow with its roots after pre-pickling with alum . With a tin pre-pickling, copper post-pickling and an ammonia development bath, the above-ground parts achieve a strong gray-green. You need about 600 grams of nettle per 100 grams of wool; Especially in the case of nettles, the color can depend on the time of picking and dyeing, which is why the technique has been forgotten in the mass production of collections.

Horticultural use

The nettles are used in various ways , especially in organic horticulture . A sharp cold water extract ("burning nettle manure") that is applied for only 24 hours as a plant strengthening agent should both increase the resistance of treated plants to pests and have a fertilizing effect. Nettle manure is used in a ratio of 1:10 to 1:20 in various vegetable plants, especially cucumbers, cabbage, leeks, tomatoes and zucchini. Stinging nettles grown in the garden or collected in the wild can also be used as tea or vegetables (wild herbs).

Cultivation

Only the greater nettle ( Urtica dioica ) is grown as a crop , mostly as a fiber plant. It is a perennial plant that is harvested for several years in a row on the same area. The cultivation is considered advantageous due to the low effort, but the plant needs nutrient-rich soil and has a high demand for water. The species can be propagated from seeds, but in large-scale cultivation vegetative propagation is standard in order to ensure uniform yields. Selected culture lines (mostly clones) are grown, the exact botanical assignment of which is not always clear; these reach heights of growth of over two meters. The first harvest takes place in the second year of growth. Yields of 3 to 12 tons per hectare of dry matter can be achieved, but higher yields usually only with intensive nitrogen fertilization. While the harvest for fiber production takes place in autumn, the harvest already takes place in spring (April) when mainly leaves are to be obtained, for example for pharmaceutical products. Cultivated plants can possibly be harvested for 10 to 15 years, but good yields are reported, according to the old cultivation experiments by Bredemann (1959), especially up to the fourth year. The annual small nettle ( Urtica urens ) is also used to grow leaves .

The cultivation of the nettle was mainly carried out in Germany and Austria during the war years as a substitute for the lack of cotton imports. At that time, about 500 hectares of nettles were grown. It was soon forgotten afterwards. However, clones from the old cultivation experiments by Gustav Bredemann have been preserved in some university collections. Since the 1990s there have been new attempts at cultivation as a renewable raw material, but these are still predominantly experimental in nature. Cultivation, as a niche product, takes place in Hungary, for example.

After the harvest, the plants are left in the field for a while in order to facilitate the insulation of the fibers through microbial degradation (analogous to the roasting of flax). The fibers are then isolated, either traditionally enzymatically through microbial degradation, or alternatively through chemical processes. Mechanical insulation is also possible, but it provides a low-quality product that cannot be used for textiles.

Cultural meaning

The long history of the nettle as a medicinal plant and food means that there are a large number of ethnobotanical traditions and views on these plant species, some of which stem from the realm of myths and beliefs in superstitions and miracles.

Some of the customs:

  • On Holy Thursday to eat nettle vegetables, to protect what for the following year before financial difficulties.
  • To hold five nettle leaves in hand to keep fear and cool.
  • On Midsummer Nettle pancakes to eat in order to be immune to Nixen- magic and elves.
  • Eating nettle cake on January 1st to ensure a good year.

swell

literature

  • Chen Jiarui (陈家瑞), Ib Friis, C. Melanie Wilmot-Dear: Urtica. In: Wu Zhengyi, Peter H. Raven, Deyuan Hong (Eds.): Flora of China . Volume 5: Ulmaceae through Basellaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 2003, ISBN 1-930723-27-X , pp. 76 (English, online ). (Sections Description and Distribution).
  • David E. Boufford: Urtica. In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 3: Magnoliophyta: Magnoliidae and Hamamelidae . Oxford University Press, New York / Oxford a. a. 1997, ISBN 0-19-511246-6 , pp. 401 (English, online ). (Sections Description and Systematics).
  • PW Ball, DV Geltman: Urtica . In: TG Tutin, NA Burges, AO Chater, JR Edmondson, VH Heywood, DM Moore, DH Valentine, SM Walters, DA Webb (eds.): Flora Europaea . 2nd, revised edition. Volume 1: Psilotaceae to Platanaceae . Cambridge University Press, Cambridge / New York / Melbourne 1993, ISBN 0-521-41007-X , pp. 80 (English, limited preview in Google Book search). .
  • Walter Erhardt, Erich Götz, Nils Bödeker, Siegmund Seybold: The great pikeperch. Encyclopedia of Plant Names. Volume 2. Types and varieties. Eugen Ulmer, Stuttgart 2008, ISBN 978-3-8001-5406-7 .
  • Eva Hanke, Ernst Wegner: The healing power of the nettle. Droemer Knaur, Munich 2000, ISBN 3-426-87041-X .
  • Heidelore Kluge: Nettle: medicinal plant and more. Haug, Heidelberg 1999, ISBN 3-7760-1751-1 .
  • Renate Spannagel: medicinal herb nettle: health care, tea preparation, cosmetic use. Weltbild, Augsburg 1998, ISBN 3-89604-731-0 .
  • Wolf-Dieter Storl : Medicinal herbs and magic plants between the front door and the garden gate. AT Verlag, Aarau / Baden 2000, ISBN 3-85502-693-9 .

Individual evidence

  1. ^ Manfred A. Fischer, Wolfgang Adler, Karl Oswald: Excursion flora for Austria, Liechtenstein and South Tyrol . 2nd, improved and enlarged edition. State of Upper Austria, Biology Center of the Upper Austrian State Museums, Linz 2005, ISBN 3-85474-140-5 .
  2. ↑ Erich Oberdorfer : Plant-sociological excursion flora . With the collaboration of Theo Müller. 7th, revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 1994, ISBN 3-8252-1828-7 .
  3. ^ Rudolf Schubert , Klaus Werner, Hermann Meusel (eds.): Exkursionsflora for the areas of the GDR and the FRG . Founded by Werner Rothmaler. 13./14. Edition. tape  2 : vascular plants . People and knowledge, Berlin 1987, ISBN 3-06-012539-2 .
  4. ↑ Hans Ernst Hess, Elias Landolt, Rosemarie Hirzel: Identification key to the flora of Switzerland . 3. Edition. Birkhäuser, Basel 1991. ISBN 3-7643-2606-9 .
  5. ↑ Carl von Linné: Species Plantarum. Volume 2, Lars Salvius, Stockholm 1753, p. 983, digitizedhttp: //vorlage_digitalisat.test/1%3Dhttp%3A%2F%2Fwww.biodiversitylibrary.org%2Fopenurl%3Fpid%3Dtitle%3A669%26volume%3D2%26issue%3D%26spage%3D983%26date%3D1753~GB%3D~ IA% 3D ~ MDZ% 3D% 0A ~ SZ% 3D ~ double-sided% 3D ~ LT% 3D ~ PUR% 3D .
  6. ↑ Carl von Linné: Genera Plantarum. 5th edition. Lars Salvius, Stockholm 1754, p. 423, digitizedhttp: //vorlage_digitalisat.test/1%3Dhttp%3A%2F%2Fwww.biodiversitylibrary.org%2Fopenurl%3Fpid%3Dtitle%3A746%26volume%3D%26issue%3D%26spage%3D423%26date%3D1754~GB%3D~ IA% 3D ~ MDZ% 3D% 0A ~ SZ% 3D ~ double-sided% 3D ~ LT% 3D ~ PUR% 3D .
  7. ↑ Recognized species based on a draft assessment by The Plant List .
  8. ↑ a b Pertti Uotila: Urticaceae. Urtica In: Euro + Med Plantbase - the information resource for Euro-Mediterranean plant diversity. Berlin 2011.
  9. ↑ a b c d e f g h i Chen Jiarui, Ib Friis, C. Melanie Wilmot-Dear: Urtica. In: Wu Zhengyi, Peter H. Raven, Deyuan Hong (Eds.): Flora of China . Volume 5: Ulmaceae through Basellaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 2003, ISBN 1-930723-27-X , pp. 76 (English, online ).
  10. ↑ a b c d e f HH Allan: Flora of New Zealand. Volume I: Indigenous Tracheophyta - Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledons. 1961, reprint 1982. ISBN 0-477-01056-3 . online .
  11. ^ Urtica in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved May 5, 2017.
  12. ↑ Plant portrait : Application and ingredients Great nettle
  13. ↑ a b c d Meret Bissegger: My wild plant kitchen . Identifying, collecting and cooking wild plants. AT Verlag, Aarau / Munich 2011, ISBN 978-3-03800-552-0 , p. 47.
  14. ^ A b Colin Randall: Historical and modern uses of Urtica. Chapter 2 in: Gulsel M. Kavalali (Ed.): Urtica. Therapeutic and nutritional aspects of stinging nettles. Taylor & Francis, London / New York 2003. ISBN 0-415-30833-X . (Medicinal and aromatic plants series - industrial profiles volume 37).
  15. ↑ Eat up Your Nettles, M. Harrison, 2010. Wild Food School, accessed July 2, 2019.
  16. ↑ CB Bouché & Hermann Grothe: History of the technical use of nettle fibers. Chapter 7 in: Carl David Bouché , Hermann Grothe: Ramie, Rheea, Chinese grass and nettle fiber. Their production and processing as a material for the textile industry. Springer Verlag, Berlin and Heidelberg 1884.
  17. ↑ Jens Soentgen : Fibers from the nettle. Retrieved May 11, 2016 .
  18. ↑ a b c C.R. Vogl & A. Hartl (2003): Production and processing of organically grown fiber nettle (Urtica dioica L.) and its potential use in the natural textile industry: A review. American Journal of Alternative Agriculture 18 (3): 119-128.
  19. ↑ H. Drangmeister: plant protection in organic farming - Fundamentals and principles. D1 General crop production. Information material about organic farming (agriculture including viticulture, fruit and vegetable growing) for teaching at agricultural vocational and technical schools. published by the Federal Ministry of Food, Agriculture and Consumer Protection 2011.
  20. ^ Barbara Schön: Teepflanzen. Cultivation in the herb garden, harvest and preparation. Brochure, published by the State Office for the Environment, Agriculture and Geology, Free State of Saxony. 2nd edition 2011.
  21. ↑ Barbara Schön: Garden Salads. Cultivation in the house and allotment gardens. Brochure, published by the State Office for the Environment, Agriculture and Geology, Free State of Saxony. 2nd edition 2011.
  22. ↑ Nicola Di Virgilio, Eleni Papazoglou, Zofija Jankauskiene, Sara Di Lonardo, Marcin Praczyk, Kataryna Wielgusz (2015): The potential of stinging nettle (Urtica dioica L.) as a crop with multiple uses. Industrial Crops and Products 68: 42-49. doi: 10.1016 / j.indcrop.2014.08.012
  23. ↑ Ilze Baltina, Lilita Lapsa, Elvyra Gruzdeviene (2012): Nettle Fibers as a Potential Natural Raw Material for Textile in Latvia. Materials Science. Textile and Clothing Technology 7 (1): 23-27.
  24. ↑ Large nettle (Urtica dioica L.), Small nettle (Urtica urens L.) Fachagentur Nachwachsende Rohstoffe e. V., industrial plants. accessed on July 2, 2019.
  25. ↑ Story of Nettle, The story of the fiber nettle Marlene. Mattes & Ammann GmbH & CO. KG, Meßstetten-Tieringen
  26. ↑ Jerzy Lutomski, Henryk Speichert: The nettle in medicine and nutrition. In: Pharmacy in our time. Volume 12, No. 6, 1983, pp. 181-186.
  27. ↑ Heinrich Marzell: The nettle in popular belief. A contribution to folklore. In: Naturwissenschaftliche Wochenschrift 26, 1911, pp. 401–406. ISSN  0369-3430 , digitizedhttp: //vorlage_digitalisat.test/1%3Dhttp%3A%2F%2Fwww.biodiversitylibrary.org%2Fpage%2F1771617~GB%3D~IA%3D~MDZ%3D%0A~SZ%3D~ double-sided%3D~LT% 3D ~ PUR% 3D .

Web links

Commons : nettles  - collection of images, videos and audio files
Wiktionary: nettle  - explanations of meanings, word origins, synonyms, translations
This article was added to the list of articles worth reading on August 10, 2019 in this version .