Rushes

Rushes
Three-leaf bulrush ( Juncus trifidus )
Systematics
Class : Bedecktsamer (Magnoliopsida) Monocots Commelinids Order : Sweet grass (Poales) Family : Rush Family (Juncaceae) Genre : Rushes
Scientific name
Juncus
L.

Schematic representation of a six-furry, hermaphrodite rush ( Juncus ) flower

The rushes (common name in Germany and partly in Switzerland and Liechtenstein) or Simsen (common name in Austria) ( Juncus ) are the namesake genus of the rush family or cornice family (Juncaceae), which has around 300 species worldwide and 29 species in Germany , is common. A characteristic feature of these perennial grasses are the rigid, rounded and bristly pointed leaf blades. These are usually hollow or filled with a spongy star parenchyma (ventilation tissue, aerenchyma ), which is used to supply oxygen.

description

The stalk-like rounded, rarely flattened leaf blades are usually hairless - in contrast to which also belongs to the bins plants Woodrush ( Luzula ). These leaf blades often continue the stem in a straight line so that the inflorescence appears laterally. Stems and leaves are filled with a spongy, white pulp or are hollow and then only divided into layers by layers of pith. The leaf sheaths are open, slit and often eyed above.

The inflorescence of the rush family is a spiral , a modified form of the panicle . The marginal or lower flowers have the longest stalk, while the central or upper ones are more compressed. This creates an almost funnel-shaped structure. Several flowers can also be grouped in a cluster. The monoecious flowers of the rushes are small and similar in structure to those of the lily family . The flower organs - six bloom cladding (tepals), six stamens (stamen) and three carpels (carpels) - are formed regularly and most complete. The bloom cladding sheets (perigone) are converted to husk- like scales. They are colored green to brown, purple or black, sometimes also transparent. The ovaries are always on top and end in three relatively long, papillary, often twisted scar branches . The number of stamens is rarely reduced to three. The pollen grains are always grouped in packs of four. The fruit type of the rushes is a multi-seeded capsule . It is divided into three parts by internal ribs (placentas).

Rushes are often evergreen. Their vegetative reproduction takes place in the majority via runners (rhizomes). Several species are clump-growing .

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  Spiraling the flutter ( Juncus effusus ) and the ball bulrush ( Juncus conglomeratus )

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  Chamois rush ( Juncus jacquinii ) with characteristic twisted stigma

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  Leaf blade with pith of blue-green bulrush ( Juncus inflexus )

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  Star parenchyma in the pith of a rush

ecology

Rushes have a star parenchyma in the pith. It is a ventilation tissue (aerenchyma). The cells receive arm-like outgrowths through localized growth of the cell wall and thus appear star-shaped. The large intercellular and lacunae facilitate gas exchange in submerged organs and increase the buoyancy of the plant body.

Rushes are windy ( anemogamy ). The flower shell is inconspicuous, nectar and fragrances are missing. The scars are often screwed in like a corkscrew in order to enlarge the surface and to be able to absorb as much pollen as possible.

The short-winged sword insect ( Conocephalus dorsalis ) is mainly bound to wetlands due to its reproductive biology. The females lay their eggs mainly in the pithy stalks of the rushes. The eggs remain in the plant stems until the next spring. The caterpillars of several species of the bag-bearer moth (Coleophoridae), especially those of the genus Coleophora, feed exclusively on Juncus species.

Rushes help purify water by breaking down pollutants . Some species can absorb phenols from the water and are used in so-called herbal sewage treatment plants .

Distribution and location

The genus is widespread worldwide, it has its main distribution center in the temperate latitudes of the northern hemisphere, but radiates into the temperate latitudes of the southern hemisphere. In the tropics, the rushes are absent in the lowlands, but are found from around 2000 meters. Of the approximately 315 species, just over forty are native to the Neotropic , seven in tropical Africa and four in tropical Asia.

The species prefer moist to wet, sometimes flooded locations in wetlands by waterways, in moors , wet meadows and in swamps .

Systematics and taxonomy

The generic name Juncus is u. a. traced back to a common Indo-European, reconstructed root form with the same meaning "rush" through ancient Irish and ancient Greek terms . There is no connection with the Latin iúngere = to bind together.

use

The combination of the soft pulp and the firm, but not rigid, flexible bark makes rushes a valued wicker material for baskets, shoes, bags, mats or traps . The term Jonc braid is derived from the French word for rush for a special type of processing. In the vernacular, however, other types of sweet grass (Poales) such as pond rushes ( Schoenoplectus ) are also called "rushes". They are all used as braiding material.

Others

The term rush is part of phraseologisms : to go into the rushes (fail, get lost); briefly also "a bulge" for a truism (a wisdom that everyone knows and which is consequently not).

Literature and further information

literature

• J. Grau, BP Kremer, BM Möseler, G. Rambold & D. Triebel: Gräser , Mosaik-Verlag, Munich 1996, ISBN 3-576-10702-9
• Henning Haeupler , Thomas Muer: picture atlas of the fern and flowering plants of Germany (= the fern and flowering plants of Germany. Volume 2). Published by the Federal Agency for Nature Conservation. Ulmer, Stuttgart 2000, ISBN 3-8001-3364-4 .
• Erich Oberdorfer : Plant-sociological excursion flora. Ulmer, Stuttgart 1994. ISBN 3-8252-1828-7 .

Individual evidence

1. ^ Manfred A. Fischer, Karl Oswald, Wolfgang Adler: Excursion flora for Austria, Liechtenstein and South Tyrol . 3rd, improved edition. Province of Upper Austria, Biology Center of the Upper Austrian State Museums, Linz 2008, ISBN 978-3-85474-187-9 , p. 1091, 1102 .
2. ^ Henrik Balslev & Alejandro Zuluaga: Flora de Colombia - Juncaceae. 2009, p. 14, Bogotá, ISSN  0120-4351
3. ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Birkhäuser, Basel / Boston / Berlin 1996, ISBN 3-7643-2390-6 (reprint ISBN 3-937872-16-7 ).
4. ↑ Rafaël Govaerts (ed.): Juncus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 17, 2018.

Web links

Commons : Rushes  - album with pictures, videos and audio files