Common dandelion

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Common dandelion
dandelion

dandelion

Systematics
Order : Astern-like (Asterales)
Family : Daisy family (Asteraceae)
Subfamily : Cichorioideae
Tribe : Cichorieae
Genre : Dandelion ( taraxacum )
Section : Common dandelion
Scientific name
Taraxacum sect. Ruderalia
Kirschner , H.Øllg. & Štěpánek
Dandelions of the genus Taraxacum

The common dandelion ( Taraxacum sect. Ruderalia ) represents a group of very similar and closely related plant species in the genus Dandelion ( Taraxacum ) from the family of the daisy family (Asteraceae). Most of these plants are simply referred to as dandelions , which means they can be confused with the genus dandelion (Leontodon) exists.

description

The dandelion is a perennial herbaceous plant that reaches a height of 10 cm to 30 cm and contains a white milky sap in all parts . Its fleshy taproot , which is up to 1 meter (rarely up to 2 meters) long, is dark brown to black on the outside. It merges into a short, strongly compressed stem axis , on which the leaves stand tightly in a basal rosette . After a violation of the vegetation point , the plant regenerates from the roots and then usually forms several leaf rosettes. The 10 to 30 cm long leaves are ovate to lanceolate, irregularly lobed, deeply incised and toothed. Incisions and teeth are strong from the base up to about two thirds of the length, further to the tip of the leaf, often less pronounced.

dandelion
Transitional stage: separated inflorescence shortly before fruit ripening; left native, right faded flower covers plucked from still immature parachutes
Detail of a ripe dandelion plant ("dandelion")

The leaf axils usually have several inflorescence stalks up to 60 cm long. Each is a leafless, hollow tube, slightly felted on the outside. At its upper end, 30 to 40 protruding bracts are densely distributed in a spiral , which soon dry out. Above this, a whorl of bracts forms an initially closed protection around the inflorescence bud. The bracts open and close protectively with the inflorescence and remain green until the fruit is ripe . The inflorescence is a pseudo-flower in which many yellow ray florets are grouped together to form a plate-shaped cup about three to five centimeters in diameter. The individual flowers open in a ring from the outside inwards. During the flowering period, which lasts several days, the inflorescence closes at night , rain or drought and finally when it fades. After several days, the bracts open for the last time when the fruit is ripe and first release the dried-on and sloughed-off umbels of the ray florets. The fruits , slender barrel-shaped achenes equipped with hairy parachutes ( pappus ) , are spread out by the wind ( paragliders ). In the vernacular the plant therefore is also called dandelion .

Cross-sectional model, Greifswald Botanical Museum

In Central Europe , the main flowering period is from April to May. Blossoms appear in significantly lower numbers until autumn.

Since some features are very plastic, the individual plants can adapt strongly to the respective locations. In undisturbed locations, plants produce long, obliquely upright leaves and up to 50 cm long, upright inflorescence stalks. On the other hand, plants on paths or meadows that have been frequently mown have much shorter leaves that lie close to the ground and prostrate stalks that are sometimes only a few millimeters long.

Analysis of the ingredients

To determine the ingredients - especially the milk juice - both spectroscopic and chromatographic methods are used, also in combination with mass spectrometry . Phenolic inositol esters, triterpene acetates and sesquiterpenoids were found to be the main components. Phenolic acids and flavonoids have been found in the roots and herbs . Antimicrobial substances could be isolated from the roots by chromatographic methods. The above-mentioned methods are also used for the determination of characteristic substances in honeys from dandelions and for forensic questions after adequate sample preparation .

Diseases

The common dandelion is attacked by the rust fungi Puccinia variabilis , Puccinia silvatica and Puccinia taraxaci . The widespread fungus Sclerotium rolfsii also colonizes the dandelion.

Systematics and distribution

The common dandelion originally comes from western Asia and Europe , but is widespread in the northern hemisphere , also through human intervention . In the southern hemisphere it occurs only sporadically and then only as a result of being dragged around. In Central Europe, it is a common weed on meadows , along roadsides and in gardens . As a ruderal plant , it quickly colonizes fallow land , rubble heaps and cracks in walls . It grows in areas with an annual average temperature of 5 to 26 ° C and an annual average precipitation of 0.3 to 2.7 m on soils with a pH of 4.2 to 8.3. In the mountains it comes to altitudes of 2800 m above sea level. NN before, but remains significantly smaller there than in the lowlands .

Since, as explained below, the populations of the common dandelion are difficult to determine with the conventional concepts of a species , they became the collective species Taraxacum officinale agg. (GH Weber ex Wiggers ) summarized. Since this cannot be separated from other collective species because of the many transitional forms, all plants are now collectively referred to as section Ruderalia of the genus Taraxacum or section Taraxacum . Depending on the author, the number of species to be recognized in this section is given between one and several thousand.

Ploidy levels

The plants are distributed geographically differently and come in several ploidy levels, each with different properties.

  • Diploid plants (2n = 16), which predominate in the southern distribution area, are fertile . They are self-incompatible and exchange their genes with other diploid plants in the usual way .
  • Triploid plants, which predominate in the northern range, are apomictic : They produce seeds by means of agamospermia (i.e. without prior fertilization ) , from which genetically identical copies ( clones ) of the mother plant are subsequently created. Since there is no mixing of the genes, mutations that z. B. express in the length and shape of the bracts or patterning of the inflorescence stalks, quickly enforce and geographically widespread. Since the triploid plants are decoupled from sexual reproduction, i.e. do not exchange their genes with other plants, all their mutation forms can be understood as independent species according to the biological and population genetic species concept . Most, if not almost all, of the species described are such apomictic mutants.
  • Tetraploid plants are found in small numbers, mainly in the northern range. If diploid plants are fertilized with their pollen , triploid offspring are predominantly produced.
  • Aneuploid plants are also found in small numbers. They are mostly apomictic and can be fertile with a suitable gene constellation.

One kind of another kind

Taraxacum officinale

As studies of different populations show, they never contain plants only one, but always several levels of ploidy. In a more closely examined population in the Netherlands , for example, 31% diploid, 68% triploid and just under one percent tetraploid plants were found. In addition, great genetic similarities between diploid and triploid plants as well as many transitional forms and natural hybrids between described species were observed. It is also unusual that triploid plants, although they do not need pollinators, still produce nectar . This suggests that the triploid plants emerged so recently that the energy-wasting nectar production could not be stopped in the course of evolution .

The entirety of these strange phenomena , viewed in isolation, is explained by the fact that the plants change their ploidy levels cyclically : Diploid plants relatively often have tetraploid offspring. Diploid plants fertilized with pollen from tetraploid plants often have triploid offspring. Triploid plants do not reproduce sexually, but accumulate mutations and spread heavily through vegetative reproduction . Through gene degradation, directly via aneuploid intermediate stages, they turn into diploid plants that distribute the accumulated mutations in the gene pool . So if the totality of all dandelion plants in the section Ruderalia is considered, it can be understood as a single species in which some members - at times - are not involved in sexual reproduction. The "switch" responsible for changing the ploidy levels, the frequency and duration of the cycles and the reason for the north-south divide in the frequency distribution of the ploidy levels are not yet known.

Possible confusion

The common dandelion is very easy to confuse with plants from other sections of the genus Taraxacum , as they look very similar and can sometimes only be distinguished by the shape of the seeds. The species from the genus Leontodon, also mentioned as dandelions, and common piglet weed are very similar. However, the inflorescence stalks of these plants are not hollow. In contrast to the genus Taraxacum, in which the achenes equipped with hairy parachutes are paragliders , the achenes in the genus Leontodon are not beaked, that is, the pappus does not sit on a stem. The yellowish-white to light brown bristle hairs of the pappus are covered with small hairs (feathered) ; they stand in one or two rows. The bristle hairs of the outer ring can be reduced to bristle scales.

use

Bee on dandelion

Due to the early appearance of its flowers, the dandelion is an important pasture for bees, which serves the development of the bee colonies in spring, but can also enable an early honey harvest in larger occurrences . Dandelion honey has a strong aroma, is golden yellow and viscous when fresh and crystallizes in fine-grained form into a yellowish honey. A colony of bees has to make over 100,000 dandelion flower visits to produce one kilogram of honey.

Children in particular make use of the inflorescence stalk, which, when spliced ​​at one end, results in a miniature reddene . If you tear the peduncle into strips and then put them into the water , spirals form due to the different absorbency of the inner and outer walls . The inner wall swells more and thus forms the outside of the curve.

Food and beverage

Bleached dandelions are available in the vegetable store

The yellow flowers are suitable for making a tasty, honey-like syrup or jelly ( French cramaillotte , with orange , lemon and sugar ) as a spread . The young, only slightly bitter-tasting leaves can be used as a salad (Austria: "Röhrlsalat"). The root can also be used as a salad or cooked. A substitute coffee was made from the dried and roasted roots of the plant in the post-war years (chicory root substitute). Dandelions are also used as animal feed.

Medicine and folk medicine

Dandelion with few seeds

The following plant parts are used:

  • Dandelion herb, Taraxaci folium ( syn.Folium taraxaci, Herba taraxaci, Taraxaci herba)
  • Dandelion root, Taraxaci radix ( syn.Radix lentis leonis, Radix taraxaci)
  • Dandelion root with herb, Taraxaci herba cum radice (syn.Taraxaci radix cum herba, Herba taraxaci cum radice, Radix taraxaci cum herba).

Active ingredients

The main active ingredients are sesquiterpene lactones - bitter substances (tetrahydroridentin B, taraxacolid-β- D -glucoside and others), a phenol carboxylic acid derivative (taraxoside), and triterpenes (taraxasterol and its derivatives ); also high potassium concentrations (up to 4.5%) and inulin (in autumn up to 40%). Recent research work in the field of ethnopharmacology investigates the physiological properties of taraxasterol. The sesquiterpene fraction seems to be responsible for the observed liver protective (hepatoprotective) effect and shows potential chemoprotective effects. For extracts from dandelion an inhibiting effect on the growth in size and the spread ( invasiveness ) of prostate and breast cancer cells as well as an apoptosis-promoting effect on liver cancer cells , leukemia cells and pancreatic cancer cells could be proven. In animal studies , a performance-enhancing and depletion detrimental effect after the administration of a dandelion extract showed where a delayed drop in blood sugar levels while simultaneously delayed increase in triglyceride - and lactate noticed.

application

The most important active ingredients of the dandelion are the bitter substances. They generally promote secretion from the digestive glands. In addition, a diuretic effect was demonstrated, which may be due to the high potassium concentration. The drugs are used for poor appetite, indigestion with bloating and flatulence, for disorders in the area of ​​the bile outflow and to stimulate urine excretion in inflammatory diseases and stone formation. The folk medicine also uses the drug as a mild laxative, in diabetes mellitus , rheumatic diseases and eczema. The fresh young leaves are also processed into spring cures as a salad, pressed juice or as an ingredient in a smoothie . The inulin-rich roots harvested in autumn serve (again today) roasted as a coffee substitute.

Contraindications are gallstone disease and obstruction of the bile ducts. Frequent contact with the milky sap of the plant can lead to contact dermatitis . In folk medicine , the stem juice is also recommended as a remedy for warts and corns

The dandelion is used homeopathically under the name Taraxacum .

Rubber substitute

During the Second World War, dandelions were used in Russia and in the German Empire (here under the Kok-Saghys project ) as a rubber substitute. Among other things, a research station for plant rubber was set up in Auschwitz concentration camp in 1942 , in which 150 to 250 forced laborers were used.

Building on the research achievements, dandelions have been viewed as a potential raw material plant for rubber for several years and researched in Europe and North America. The aim of the research is to obtain usable dandelion rubber from the Russian dandelion (Taraxacum kok-saghyz) as an alternative to the natural rubber commonly used today from the milky sap of the rubber tree (Hevea brasiliensis) and synthetic rubber .

Common names

The many vernacular and colloquial names of the dandelion reflect its distribution and importance. Some of these names refer to its diuretic effect ( diuretic ): bed wetter , Bettpisser , bed sailor , Bettseecher , Bumbein , Bumbaum , Hundeblume , dog flower , Kuhblume , Moadogga , mill bushes , Pissblume (Dutch: pissebloem) pisser , Pissnelke , dandelion , Rahmstock , Ringelstock , in Switzerland Chrottepösch (e) , Weihfäcke (feathers of a consecration), Milchblueme or Söiblueme , in France pissenlit . Some names such as corn stick also refer primarily to the period of the first flowering.

In parts of northern Germany , the dandelion is called a buttercup or butter stick while it is in bloom . The Swiss German name Söiblueme ("Saublume") expresses the fact that some farmers do not like to see this plant in their meadows, where it spreads too much. In the canton of Schaffhausen (CH) the dandelion is also called Häälestock , in the canton of Appenzell Innerrhoden (CH) it is called Sonnwendlig , because the flower always turns towards the sun during the course of a day. For the rural Muotathaler Wettererschmöckern , the dandelion is a weather sign : If it is still open towards evening, the weather tends to be bad. In the Rhineland the term chain herb is occasionally used, which can be traced back to the fact that children make chains by sticking the hollow stems together.

The name Mellichstock or Millichstock , which is widespread in Itzgründischen , alludes to the milky juice. The traditional South Thuringian cuisine also knows several dishes in which dandelion is used. In Lauscha , the Mellichstöckdooch is celebrated on the first Saturday in May, on which these dishes are presented and offered. Here the flowering plant is also referred to as Laüsblömla ("lice flowers").

In the Vogtland dialect ( Vogtland region in Saxony ) the dandelion plants are also called "Hosnblaatle", i.e. hare leaves, as they are used as animal food for hares and rabbits, among other things.

Dandelions on banknotes

The 500 DM banknote depicting a dandelion by Maria Sibylla Merian (1679)
50-franc note of the ninth series (2016)

On the back of the 500 DM banknote , from 1992 onwards, a dandelion from a book by Maria Sibylla Merian from 1679 was depicted, on which a caterpillar and a butterfly of the gray extensor foot are sitting.

The 50- franc note of the ninth series (2016) designed by Manuela Pfrunder shows a hand-held dandelion blossom on the front.

literature

  • Jan Kirschner, Jan Štěpánek: Again on the Sections in Taraxacum (Cichoriaceae) (Studies in Taraxacum 6). In: Taxon. Volume 36, No. 3, 1987, pp. 608-617 (with the first description of Taraxacum sect. Ruderalia by Jan Kirschner, Hans Øllgaard & Jan Štěpánek on p. 615, JSTOR 1221855 .
  • JE Simon, AF Chadwick, LE Craker: Herbs: An Indexed Bibliography. The Scientific Literature on Selected Herbs, and Aromatic and Medicinal Plants of the Temperate Zone 1971/80. Elsevier / Archon, Amsterdam / Hamden, Conn. 1984.
  • Steph BJ Menken, Eric Smit, Hans CM Den Nijs: Genetical Population Structure in Plants: Gene Flow between Diploid Sexual and Triploid Asexual Dandelions (Taraxacum Section Ruderalia). In: evolution. Vol 49, No. 6, 1995, pp. 1108-1118, JSTOR 2410435 .
  • Peter van Baarlen, Peter J. van Dijk, Rolf F. Hoekstra, J. Hans de Jong: Meiotic recombination in sexual diploid and apomictic triploid dandelions (Taraxacum officinale L.). In: Genome. Volume 43, No. 5, 200, pp. 827-835, doi: 10.1139 / g00-04 .
  • MH Verduijn, Peter J. van Dijk, JMM van Damme: The role of tetraploids in the sexual-asexual cycle in dandelions (Taraxacum). In: Heredity. Volume 93, No. 4, 2004, pp. 390-398, doi: 10.1038 / sj.hdy.6800515 .
  • Ingrid Schönfelder, Peter Schönfelder : The new manual of medicinal plants. Franckh-Kosmos, Stuttgart 2004, ISBN 3-440-09387-5 .
  • Ben-Erik van Wyk, Coralie Wink, Michael Wink : Handbook of medicinal plants. Wissenschaftliche Verlagsgesellschaft, Stuttgart 2004, ISBN 3-8047-2069-2 .

Web links

Wiktionary: dandelion  - explanations of meanings, word origins, synonyms, translations
Commons : Common dandelion  album containing pictures, videos and audio files

Individual evidence

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