Poison lettuce

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Poison lettuce
Poison lettuce (Lactuca virosa), illustration

Poison lettuce ( Lactuca virosa ), illustration

Systematics
Euasterids II
Order : Astern-like (Asterales)
Family : Daisy family (Asteraceae)
Subfamily : Cichorioideae
Genre : Lettuce ( Lactuca )
Type : Poison lettuce
Scientific name
Lactuca virosa
L.

The Poison lettuce ( Lactuca virosa ), also Wild lettuce , Stinklattich or Stinksalat called, is a close relative of lettuce , a kind from the kind of lettuces ( Lactuca ) from the family of the daisy family (Asteraceae). Its leaves and the dried milk juice , the lactucarium , is classified as highly toxic and was used as a sedative and as an opium substitute until 100 years ago.

description

Poison lettuce ( Lactuca virosa )
Poison lettuce seeds

The Lactuca virosa is a one- to two-year , herbaceous , the most 60 cm plant to 120, often 2 meters. The roots are spindle-shaped, branchy and have an unpleasant smell of poppy seeds .

The upright, cylindrical, milky sap-bearing stalk has a whitish and often reddish color and is branched in panicles above. It is leafed up in the lower half or a little higher. At first it forms a basal rosette of leaves that can reach a diameter of over 30 cm and from which a long stem with the flowers grows in the summer of the first or second year. All Lactuca species go through a phase of intense height growth ("shooting") before flowering.

The leaves have a bitter to pungent taste, are blue-green, horizontally aligned and mostly undivided, rarely slightly lobed, egg-shaped and spiky-bristled on the underside of the central rib . Its edge is serrated to a point. The basal leaves are narrowed at the base into a petiole, the stem leaves are sessile with a heart-arrow-shaped base encompassing the stem.

In an elongated pyramid-shaped panicle-like overall inflorescence, the panicle branches are covered with flower heads along their entire length . The oval-cylindrical shell is 10 to 12 mm long; the bare, whitish at the edge, red at the tip bracts are arranged like a roof. The light yellow ray florets tower above the shell. The pollination is done either by insects or through self-pollination . As with many other species in the subfamily Cichorioideae , the sepals of the flowers eventually transform into an umbrella-shaped pappus , which enables the seeds attached to it to be distributed as an umbrella flyer with the wind ( meteorochory ) or hanging on the fur of animals ( zoochory ). The fruits have five ribs on both sides and are darkly hairy.

The flowering period lasts from July to September. After the seeds are distributed, the plant dies.

The number of chromosomes is 2n = 18.

Confusion with other plants

Poison lettuce: The leaf marginal teeth are clearly visible

There is a risk of confusion with the vegetable goose thistle , whose leaves have no thorns; with the wild cardoon , which has pale violet flowers and whose opposite leaves are prickly on the underside not only along the central vein; and with other species of lettuce , especially the prickly lettuce , which is usually easy to recognize by the much more strongly incised, strictly vertical leaves. Plants with moderately twisted, more or less undivided leaves can be identified most reliably by the fruits, which are bristly-toothed in the spiny lettuce.

Location and distribution

The poison lettuce is not found everywhere in Germany , mainly on the Moselle , where it was grown in vineyards, in the Rhineland and on the Main . There is still a high occurrence in Saxony-Anhalt . As a warmth -loving plant from the Mediterranean, it grows in dry, nutrient-rich herbaceous and perennial weeds in southern, central and western Europe, but also in Eastern Europe as far as Hungary and Poland , as well as in North Africa to Western Asia. In the USA it was introduced in a few states.

According to Ellenberg , the poison lettuce is a half-light plant that shows warmth to extreme heat, maritime climate, drought to freshness, weak bases and nitrogen abundance. Salt or heavy metals are not tolerated. According to Oberdorfer, it thrives in companies of the Alliarion association, but also in those of the Thlaspietea rotundifolii class.

ecology

The plant provides a habitat for insects: among other things, the larvae of the gamma owl ( Autographa gamma ), the butterfly Eucosma conterminana and the now rare compass lettuce owl ( Hecatera dysodea ), but also aphids feed on it. On the other hand, the poison lettuce defends itself against predators with the bitter substances released in the milky sap (see ingredients), which are produced to a large extent during the period of the plant's shooting and the subsequent flowering period. In general, injuries are sealed up with the rubbery main component of the juice, lactucerin, and intruders such as mushrooms are killed with phytoalexins . The poison lettuce is resistant to the salad Varicosavirus and downy mildew of lettuce ( Bremia lactucae ), and this resistance have been successful in lettuce - breeding lines crossed (re).

Taxonomy and systematics

The scientific name Lactuca virosa was first published in 1753 by Carl von Linné in Species Plantarum .

One can distinguish the following subspecies:

  • Lactuca virosa subsp. cornigera (Pau & Font Quer) Emb. & Maire : It occurs only in Morocco.
  • Lactuca virosa subsp. livida (Boiss. & Reut.) Ladero & A. Velasco : It only occurs in Spain.
  • Lactuca virosa subsp. virosa : It is originally found in Morocco, Algeria, Madeira, Portugal, Spain, France, Italy, Belgium, the Netherlands, Germany, Austria, Switzerland, Slovenia, Macedonia, Greece and Romania. It is a neophyte in Croatia, the southern United States, Australia, and New Zealand.

use

history

Poison lettuce has been used as a medicinal plant since ancient times. First in the Mediterranean , later in other regions, its allegedly calming, diuretic effect was appreciated. For example, Hippocrates wrote in 430 BC. About the different benefits of wild lettuce and lettuce. The Roman agricultural writer Columella described four types of lettuce / lettuce in 42, and Pliny only 57 years later, nine. Emperor Augustus is said to have made the poison lettuce responsible for his recovery from a serious illness and was so impressed that he had a statue erected in honor of his personal physician Antonius Musa . Presumably with the expansion of the Roman Empire , the lettuce plants spread to other parts of Europe.

Towards the end of the 18th century, more and more doctors are said to have used the dried milk juice of the poison lettuce (the lactucarium) as an opium substitute . Around 1847 the plant was grown on a large scale in the Moselle area , and the Lactucarium obtained was shipped from Zell via England to the USA. In other European countries, too, there was an increase in the cultivation of wild lettuce.

By the end of the 19th century poison Cos preparations were in Germany be official , that is in German Pharmacopoeia was added (DAB). Preparations were still described in the British Pharmaceutical Codex in 1911 . Either because of the laborious harvest or because of the lack of scientific evidence of its effect, it was eventually replaced by opium from Asia.

The plant celebrated a surprising rediscovery in the 1970s, when its effects became known in hippie circles in the USA. A German company then developed a preparation based on Lactucarium and launched the drug on the market with effective advertising, but since the preparation was not optimal and did not work, the public issue quickly calmed down.

ingredients

Of the in the genus lettuces specified ingredients of the poison lettuce has a great deal of bitter substances on. The general nutritional values ​​of lettuce leaves for humans are: 1 to 2% carbohydrates , 1 to 2% protein and 0.25% fat . The rest consists mainly of water and indigestible fiber.

The dried leaves and especially the lactucarium must be classified as highly toxic . Ingestion of significantly more than a gram of Lactucarium initially causes headache, sweats and dizziness. According to Hager, "normal use, however, resulted in practically never serious poisoning". In animals, especially in smaller mammals, the poison lettuce is a danger and can lead to death as a result of cardiac arrest. The lethal dose in mice is 0.5 to 0.6 g of sesquiterpene lactones per kg of body weight.

Lactuside A

It is not known exactly which of the ingredients are responsible for the plant's previously claimed medicinal effects. An early study of the US state pharmacies found only a weakly calming effect. Newer laboratory studies are cited in Hager, which not only show an effect in the mouse experiment, but also that the active substance is one of the water-soluble components, but not lactucin, lactucopicrin or jacquinelin. A glycoside fraction with the main component lactuside A also proved to be effective. However, the information in the cited papers is said to have been too imprecise for a comparative or even conclusive assessment.

Substances that have been pharmacologically proven to be effective and are also responsible for the poisonous effect belong to the active ingredient class of the sesquiterpene - lactones . The substances lactucin, lactucopicrin and 11β, 13 dihydrolactucin were obtained from the poison lettuce and related species of the genera Lactuca. In animal experiments, they were tested as pain relievers on mice and their effectiveness was confirmed.

use

From the poison lettuce to the 19th century, the dried milk juice, known as lactucarium, was used. Tea was made from the leaves and the lactucarium was taken directly. In both cases a calming, analgesic, sleep-promoting effect is reported. It was also used against coughing and as a diuretic . It is possible that all spontaneous occurrences in Germany can be traced back to such overgrown medicinal plants.

cultivation

The poison lettuce is sown from March at a distance of 30 to 40 cm, preferably in a stony and sunny location without standing moisture. The harvest begins with the flowering period and lasts until the end. All the herbs above the earth are used, either the leaves are dried as tea or pressed, or the plant is cut as a milky sap.

See also

swell

  1. ↑ a b c d e f g Gerhard Wagenitz (Ed.): Illustrated flora of Central Europe. Pteridophyta, Spermatophyta . Founded by Gustav Hegi. 2nd revised and expanded edition. Volume VI. Part 4: Angiospermae, Dicotyledones 4 (Compositae 2, Matricaria - Hieracium) . Paul Parey, Berlin / Hamburg 1987, ISBN 3-489-86020-9 , pp. 1122–1124 (revised reprint of the 1st edition (Volume VI / 2 from 1929) with addendum).
  2. ↑ a b c John L. Strother: Lactuca. In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 19: Magnoliophyta: Asteridae, part 6: Asteraceae, part 1 (Mutisieae – Anthemideae). Oxford University Press, New York / Oxford a. a. 2006, ISBN 0-19-530563-9 , pp. 262 (English, online ). (engl.).
  3. ^ A b Oskar Sebald, Siegmund Seybold, Georg Philippi, Arno Wörz (eds.): The fern and flowering plants of Baden-Württemberg . tape 6 : Special part (Spermatophyta, subclass Asteridae): Valerianaceae to Asteraceae . Eugen Ulmer, Stuttgart (Hohenheim) 1996, ISBN 3-8001-3343-1 , p. 342-343 .
  4. ^ Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp. 989 .
  5. ↑ Poison lettuce. In: FloraWeb.de.
  6. ↑ GS Robinson et al. a .: HOSTS - a database of the hostplants of the world's Lepidoptera. online .
  7. ↑ Freundeskreis Botanischer Garten Aachen eV, The Karlsgarten in Melaten. 2005. online .
  8. ↑ Carl von Linné: Species Plantarum. Volume 2, Lars Salvius, Stockholm 1753, p. 795 ( digitized versionhttp: //vorlage_digitalisat.test/1%3Dhttp%3A%2F%2Fwww.biodiversitylibrary.org%2Fopenurl%3Fpid%3Dtitle%3A669%26volume%3D2%26issue%3D%26spage%3D795%26date%3D1753~GB%3D~ IA% 3D ~ MDZ% 3D% 0A ~ SZ% 3D ~ double-sided% 3D ~ LT% 3D ~ PUR% 3D ).
  9. ↑ a b c Werner Greuter (2006+): Compositae (pro parte majore). - In: W. Greuter & E. von Raab-Straube (ed.): Compositae. Euro + Med Plantbase - the information resource for Euro-Mediterranean plant diversity. Datasheet Lactuca virosa In: Euro + Med Plantbase - the information resource for Euro-Mediterranean plant diversity.
  10. ↑ a b Lactuca in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved April 13, 2018.
  11. ↑ R. Santich: Lettuce. From Wild Weed to Functional Food. In: Practical Hydroponics & Greenhouses. Volume 78, 2004, [1]
  12. ↑ J. on the Hövel: Lactucarium. (online) .
  13. ↑ a b W. Blaschek et al. (Hrsg.): Hager's handbook of pharmaceutical practice. Volume 3: Drugs L – Z. 5th edition. Springer, Berlin 1998, ISBN 3-540-61619-5 , p. 21 ff.
  14. ^ Poison plants, H. Liebenow / K Liebenow, VEB Gustav Fischer Verlag Jena 1988, p. 84, ISBN 3-334-00209-8
  15. ↑ W. Beltman, AJHP van Riel, APG Wijnands-Kleukers, MF Vriesman, IS van den Hengel-Koot, I. de Vries, J. Meulenbelt: smart shops. Overzicht van producten, claimde werking en hun medical-toxicological relevance. Rijksinstituut voor Volksgezondheid en Milieu . RIVM rapport 348802 017, 1999.
  16. ↑ JP Remington, HC Wood et al. (Ed.): The Dispensatory of the United States of America. Lactuca. 1918 ( online ).
  17. ↑ A. Wesołowska, A. Nikiforuk, K. Michalska, W. Kisiel, E. Chojnacka-Wójcik: Analgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice. In: Journal of Ethnopharmacology . Volume 107, No. 2, 2006, pp. 254-258, doi : 10.1016 / j.jep.2006.03.003 .

Web links

Commons : Lactuca virosa  - album with pictures, videos and audio files