bracken

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bracken
Bracken (Pteridium aquilinum)

Bracken ( Pteridium aquilinum )

Systematics
Ferns
Class : True ferns (Polypodiopsida)
Order : Spotted ferns (Polypodiales)
Family : Bracken family (Dennstaedtiaceae)
Genre : Bracken ( Pteridium )
Type : bracken
Scientific name
Pteridium aquilinum
( L. ) Kuhn

The bracken ( Pteridium aquilinum ) is a showy fern that is widespread worldwide .

features

The pinnate plumage of a bracken fern
Bracken ( Pteridium aquilinum ), illustration

The bracken has a branched rhizome that creeps in the ground , which can become very large and old.

Each year the individually standing, slightly overhanging fronds arise on the rhizome. In contrast to other ferns found in Central Europe, these are 3 to 4-fold pinnate and usually 0.5 to 2 meters high. Under favorable conditions, leaning against it, however, they can also reach heights of up to 4 meters.

The Sori stand on the edge of the underside of the leaflet and are not only covered by a veil ( indusium ), but also by the rolled edge of the leaflet.

The number of chromosomes is 2n = 104.

ecology

The bracken is a frost-sensitive rhizome - geophyte , a spreader climber and the largest native fern. It forms a VA mycorrhiza , a special form of symbiosis with a fungus that is in contact with the fine root system of the plant.

In contrast to the other native ferns, the spore structures ( sporangia ) are found under the rolled leaf edge and there are no separate sori . However, the spores only form in sunny, mild climates; they spread out as grain fliers through the wind. Spore ripening is in October.

During sexual reproduction, the spore does not initially produce a new fern, but a leaf-shaped green pre-germ with a simple ( haploid ) set of chromosomes, the prothallium . The prothallium then forms the actual germ cells. If water is present as a medium in which the mature germ cells can move, fertilization then takes place. A new diploid fern plant with a complete set of chromosomes is created from the fertilized egg cell of the prothallium.

The vegetative reproduction takes place through the long underground creeping shoots (rhizomes). Rhizomes up to 60 m in length have been found in Finland, corresponding to an assumed age of 1,500 years. The bracken avoids lime .

Toxicity

The entire plant is poisonous. The young leaves contain the highest levels of active ingredients such as hydrogen cyanide glycosides . In adulthood, the plant produces a wider range of toxins, including the enzyme thiaminase , ptaquiloside , an unstable glycoside , and a saponin , pteridine .

Reactions to the plant result from the consumption habits and the associated amount consumed as well as the sensitivities of the consumers. Which part of the plant and at what time of year it is consumed can also have an influence on the type of damage.

Poisoning in horses , goats and pigs is shown by a vitamin B1 -destructive effect, caused by the enzyme thiaminase. The consequences for the animal are disorders of the central nervous system, which can be perceived from the outside through resulting disorders in the movement sequence or motor disorders . The reactions to cattle are different. Poisoning becomes visible through the occurrence of bleeding in the mouth, nose and metabolic organs - blood is found in stool and urine ("blood urine"). The development of bladder and colon cancer in cattle that eat the plant is also considered proven. Since the above-ground parts of the plant retain their poisonous effect even after drying, cow's milk also poses a risk to humans. Small vertebrates such as rabbits are also known to be blind and cancerous.

In some areas of the USA, Japan and New Zealand, however, the bracken is eaten young by humans as a wild salad . An increased incidence of tumors of the esophagus and gastric cancer in these areas is associated with it.

In Japan, the young sprouts are placed in a hot baking soda solution overnight before they are eaten before they are boiled in fresh water the next day. They have a slimy consistency and are usually eaten cold with soy sauce. Starch is also obtained by leaching from the crushed rhizomes, which is used for desserts, but is increasingly being replaced by a surrogate made from sweet potato starch.

distribution

The bracken is found worldwide. It is only absent in the polar regions and in deserts. In Central Europe it is common and widespread everywhere. In some rainy areas such as Ireland or Scotland, the bracken dominates entire landscapes.

In the Allgäu Alps , it rises up to 1600 m above sea level on the Söllerkopf near Oberstdorf.

It likes to grow in light forests, on the edges of forests and from such forest edges underground in meadows and pastures out into high and dense stands that displace the grass growth or in bushes on acidic subsoil. In soils that are poor in nutrients, it can form mass populations after clear cuts or forest fires . In sparse pine forests, too, it often dominates the herbaceous layer . It occurs in Central Europe in plant communities of the Pruno-Rubion, the Quercion roboris and the Luzulo-Fagenion.

Dense bracken stands are problematic for forestry because they have a “damming” effect, namely making almost any natural regeneration of trees impossible and can quickly darken trees planted on forest cultivated areas. In the case of unused agricultural land, bracken can also occasionally spread rapidly and prevent it from being used again. Therefore herbicides with glyphosate are used against the bracken if necessary . Mechanical or biological control shows less success.

In the district of Lörrach , on both sides above the Wiesental between Todtnau and Zell , the bracken is spreading on high pastures that are already hectare-sized and no longer used and in particular displaces forage grasses and herbs in these historical cultivated landscapes . As part of a major nature conservation project in the southern Black Forest, attempts are being made to push back the fern without chemical support by mowing and mulching as well as by resuming grazing. A dense clonal bracken growth is to be preserved as protection against erosion on very steep and more south-facing slopes .

use

One for the Bela Krajina typical Steljnik where bracken as bedding was grown for stables

Despite its toxicity , young bracken is eaten regionally as a salad or vegetable.

In the Weißkrain , bracken was cultivated as litter in so-called steljniki (litter forests , from Slovenian stelja 'litter' ) .

Systematics

The systematics of the bracken is rather unclear. Sometimes it is considered the only species in its genus, and sometimes a few other tropical species are assigned to the genus Pteridium . Depending on the author, it belongs to one of the families Dennstaedtiaceae , Hypolepidaceae or Pteridaceae . Their classification in an order is in turn handled differently.

Pteridium aquilinum subsp. aquilinum hairy leaf spindle and ciliate leaf pinna from below

In Central Europe, two subspecies are distinguished:

  • Pteridium aquilinum subsp. aquilinum : With hairy leaf spindle. Occurrence in the whole range of the species.
  • Pteridium aquilinum subsp. latiusculum (Desv.) Underw. ex A. Heller : With almost bare leaf spindle and always non-lashed leaflets. North Central Europe and North Europe, Asia and North America.

literature

  • Ruprecht Düll , Herfried Kutzelnigg : Pocket dictionary of plants in Germany and neighboring countries. The most common Central European species in portrait. 7th, corrected and enlarged edition. Quelle & Meyer, Wiebelsheim 2011, ISBN 978-3-494-01424-1 .
  • Manfred A. Fischer , Karl Oswald, Wolfgang Adler: Excursion flora for Austria, Liechtenstein and South Tyrol. 3rd, improved edition. State of Upper Austria, Biology Center of the Upper Austrian State Museums, Linz 2008, ISBN 978-3-85474-187-9 .
  • Thomas Gaskell Tutin et al .: Flora Europaea. Volume 1: Psilotaceae to Platanaceae . Second edition, Cambridge University Press, Cambridge (UK) 2010, ISBN 978-0-521-15366-9
  • Christiane Volger : The bracken and its control with aminotriazole . Series of publications by the Forestry Faculty of the University of Göttingen and communications from the Lower Saxony Forest Research Institute (Volume 41). Sauerländer, Frankfurt am Main 1969, 104 pages.
  • Bernhard Marbach and Christian Kainz: Ferns, mosses, lichens . Second edition, BLV Buchverlag, Munich 2010, ISBN 978-3-8354-0664-3 , p. 18.

Individual evidence

  1. ^ A b Bernhard Marbach and Christian Kainz: Farne, Moose, Lichen . Second edition, BLV Buchverlag, Munich 2010, ISBN 978-3-8354-0664-3 , p. 18.
  2. ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . 8th edition, Verlag Eugen Ulmer, Stuttgart 2001. Page 74. ISBN 3-8001-3131-5
  3. ^ Bracken, Pteridium aquilinum. Botanikus.de, accessed on August 24, 2018.
  4. ↑ Ed. M. Potter and Mark S. Baird: Carcinogenic effects of ptaquiloside in bracken fern and related compounds. In: British Journal of Cancer . Volume 83, number 7, October 2000, pp. 914-920, doi : 10.1054 / bjoc.2000.1368 , PMID 10970694 , PMC 2374682 (free full text).
  5. ↑ Erhard Dörr, Wolfgang Lippert : Flora of the Allgäu and its surroundings. Volume 1, IHW, Eching 2001, ISBN 3-930167-50-6 , p. 65.
  6. ↑ Maxi Boronczyk, Andrea Hahne, Kristin Hess and Bianca Rau: Bracken problem plant: The effects on biodiversity and various strategies for control. ( Memento of December 8, 2015 in the Internet Archive ) In: Pulsatilla. Issue 8, 2005, pp. 33–39 (PDF, accessed on November 29, 2015).
  7. ↑ Measures: Bracken control. Major nature conservation project Feldberg-Belchen-Oberes Wiesental, accessed on June 8, 2019.
  8. ^ Theodor CH Cole: Dictionary of Foods - Dictionary of Foods ( limited preview in Google book search).
  9. ↑ Michael Ashkenazi, Jeanne Jacob: Glossary entry warabi. In: The Essence of Japanese Cuisine: An Essay on Food and Culture ( limited preview in Google Book search).
  10. ^ The Land of Birch Trees :: Prvi interaktivni multimedijski portal, MMC RTV Slovenija. rtvslo.si, accessed September 25, 2018 .
  11. ^ Metlika - Slovene regions and municipalities in numbers. stat.si, accessed on September 25, 2018 .
  12. ^ Pteridium in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.

Web links

Commons : Bracken ( Pteridium aquilinum )  - Album with pictures, videos and audio files
Wiktionary: Bracken  - explanations of meanings, word origins, synonyms, translations