Autumn rootwort

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Autumn rootwort
Autumn rootwort (Spiranthes spiralis)

Autumn rootwort ( Spiranthes spiralis )

Systematics
Family : Orchids (orchidaceae)
Subfamily : Orchidoideae
Tribe : Cranichideae
Sub tribus : Spiranthinae
Genre : Drehwurzen ( Spiranthes )
Type : Autumn rootwort
Scientific name
Spiranthes spiralis
( L. ) Chevall.

The Herbst-Drehwurz ( Spiranthes spiralis ), also called rotary ear , screw stendel or autumn spiral ear , from the genus of the Drehwurzen ( Spiranthes ) is the most recently blooming native orchid species . The scientific generic name Spiranthes is formed from the Greek words σπεῖρα "speira" for everything twisting, twist and νθος "anthos" for flower, blossom and refers to the spiraling inflorescence of the plant. The Latin species name spiralis also indicates this connection. The German name Herbst-Drehwurz also refers to the late flowering period. Due to the special demands placed on its location, the autumn rootwort has become very rare.

description

This very graceful, persistent herbaceous plant reaches heights of between 5 and 30 centimeters. This geophyte has two beets as storage organs, which also absorb the water as roots. No additional roots are formed. As a rule, two new beets are formed from autumn until the plant is drawn in, and more rarely only one or three. The old ones are slowly dying off. The leaf rosette is usually formed from three to seven glossy leaves lying close to the ground , which are 1.5 to 3.5 cm long and 1 to 1.5 cm wide.

There are three to five sheathed leaves along the stem . It is particularly hairy in the area of ​​the flower spike and gives it a gray-green appearance. The annual inflorescence is 3 to 12 cm long and more or less spirally twisted. The small flowers are fragrant. The three bracts of the outer, the two of the inner circle of perigone and the lip are about 5 to 7 mm long. The edge of the lip is notched and, when viewed up close, appears frayed.

The number of chromosomes is 2n = 30.

The growth cycle during the growing season of this species differs greatly from that of other native orchids: the flower shoots begin to grow between July and August. At this time, no leaves are visible yet. During the flowering period between late August and early October, they sprout directly next to the flower shoot. They outlast winter and wither by the beginning of summer. The next flower shoot then grows from the center of the no longer present rosette of leaves.

ecology

The fruit set of the lower and middle flowers of an ear is almost complete; the flowers in the upper quarter usually wither. The autumn rootwort is considered allogamous . Pollinators are bumblebees that visit the spiraling inflorescences from bottom to top. The flowers produce a vanilla-like scent and nectar that is collected at the end of the lip. The clinadrium prevents the pollinia from falling, so that autogamy is impossible. Due to a narrow gap between the lip and the rostellum , only the pollinia can be removed from freshly opened flowers with the help of a single boat-shaped adhesive disc. In the advanced stage of flowering, access to the stigma is widened so that the pollinia can be transmitted from the bumblebee's trunk. Older flowers can only be pollinated with the pollen from younger flowers. It is unclear whether bumblebees are the only pollinators.

distribution

The range of the species includes Europe with the exception of the colder areas in the north, the species also occurs in North Africa , the Caucasus and northern Persia .

Like many other native orchids, for example the Ragwurzen ( Ophrys ), the original origin of the Herbst-Rotwurz is the Mediterranean area . It was only when humans between 7,000 and 4,000 BC When it became settled and cleared forests in order to farm and raise cattle, the habitats for this orchid were created and the spread to the north began.

In Germany, the main areas of distribution are on the Franconian Heights , in the Franconian Jura , the foreland of the Swabian Alb and in the Alpine foreland . Few locations exist in southern Saxony-Anhalt . Outside of these areas, the plant can only be found very rarely. In the west and north-west of Germany all locations are probably extinguished.

In Austria the species is still found in all federal states, but is also rare.

In Switzerland , most of the current evidence is located at Lake Lucerne , in the Rhine Valley near Chur , in the Walensee area and in Ticino .

Locations and distribution in Central Europe

The autumn rootwort needs rather low-lime, dry, humus-rich loamy soil. It colonizes dry grasslands that are regularly grazed by sheep. Obviously, their development is linked to regular grazing by sheep. At least the species has disappeared in all places where sheep have stopped using pasture. Why the development of this orchid is linked to grazing by sheep is not yet clear. Occasionally the autumn rootwort also occurs on the edge of marsh meadows, in dune valleys and in sparse pine stands, provided that grazing by sheep takes place here as well. The autumn rootwort loves summer warmth. It is very rare in Central Europe, but mostly occurs in loose populations with few individuals at its locations. In the low mountain ranges, in the foothills of the Alps and in the Alps, it usually only rises to around 800 m. According to Baumann and Künkele , the species has the following altitude limits in the Alpine countries: Germany 20–1160 meters, France 1–1500 meters, Switzerland 253–1640 meters, Liechtenstein 500–800 meters, Austria 250–1000 meters, Italy 41–1320 meters, Slovenia 50-1000 meters. In Europe the species occurs between 1 and 1640 meters above sea level, in the Mediterranean area only between 0 and 800 meters above sea level.

Location

Typical location on the Frankenhöhe , together with the common heather

The autumn rootwort grows on poor grass , dry , semi- arid grass and heathland with regular grazing, which keeps the accompanying vegetation low. It is also very rarely found in sparse coniferous forests.

Typical accompanying plants are often the Spiny Restharrow ( Ononis spinosa ), heather ( Calluna vulgaris ) and the stiffness Augentrost ( Euphrasia stricta ).

The soils of the biotopes are usually superficially acidified, which is also indicated by various accompanying plants, e.g. B. the common heather. They are rarely found together with lime-loving plants. For example on the edge of the Nördlinger Ries it grows together with the silver thistle and the common pasque flower , both of which are lime-loving.

After the dry summer of 2003, there were little to no flowering plants. Late flowering in October was expected, but this assumption was not confirmed.

Plant communities:

  • Association Mesobromion erecti (semi-arid grassland, poor meadows and pastures)
  • Violion caninae association (low-lying grass turf)
  • Association Molinion caeruleae (litter meadows, drier form)

(For a breakdown see plant sociological units according to Oberdorfer )

Conservation and endangerment

Like all orchid species found in Europe, the autumn rootwort is under strict protection of European and national laws.

In the other federal states this species does not or no longer occur.

The autumn rootwort is dependent on the regular grazing of its locations by sheep. If this is abandoned, the surfaces quickly become matted and the less competitive species is overgrown by larger plants and no longer receives enough light for photosynthesis . At first there are no flowers, after a few years the plants also disappear. Grazing that is too strong or carried out at the wrong time also poses a threat. If the flocks of sheep stay too long on the sites during the flowering period, the flower stems are either eaten away or trampled. A flock that moves quickly through usually leaves enough flowering shoots, the seeds of which ensure the conservation of the species.

The population development in Germany, Austria and Switzerland is decreasing.

To draw attention to this in Central Europe with extinction endangered species, it was in 2001 by A rbeitskreis H eimische O rchideen to (AHO) in Germany Orchid of the Year explained.

Systematics

Carl von Linné described this species as Ophrys spiralis ( Basionym ) in 1753 . At that time the orchids with spurless flowers were placed in the genus Ragwurzen ( Ophrys ). In addition to the valid name Spiranthes spiralis (L.) Chevall. In 1827 there are still the following synonyms :

  • Epipactis spiralis (L.) Crantz 1769
  • Serapias spiralis (L.) Scop. 1772
  • Ophrys autumnalis Balb. 1801
  • Neottia spiralis (L.) Sw. 1805
  • Neottia autumnalis (Balb.) Pers. 1807
  • Ibidium spirale (L.) Salisb. 1812
  • Spiranthes autumnalis (Balb.) Rich. 1817
  • Neottia autumnalis (Balb.) Steud. 1821
  • Gyrostachys autumnalis (Balb.) Dumort. 1827
  • Spiranthes glauca Raf. 1837
  • Gyrostachys spiralis (L.) Kuntze 1891

hybrid

A hybrid with the summer rootwort ( Spiranthes aestivalis ) has been described.

  • Spiranthes × zahlbruckneri H.Fleischm.

Due to the different biotopes of these species, the hybrid is very rare. There should be evidence from Austria and France.

More pictures

literature

Standard literature on orchids

  • Karl-Peter Buttler : Orchids, the wild growing species of Europe . Mosaik Verlag, 1986, ISBN 3-570-04403-3 .
  • Helmut Baumann , Siegfried Künkele: The wild growing orchids of Europe . Franckh, 1982, ISBN 3-440-05068-8 .
  • Robert L. Dressler: The orchids - biology and systematics of the Orchidaceae . 1996.
  • Hans Sundermann : European and Mediterranean orchids . 2nd Edition. Brücke-Verlag, 1975, ISBN 3-87105-010-5 .
  • JG Williams: Orchids of Europe with North Africa and Asia Minor . BLV Verlag, ISBN 3-405-11901-4 .
  • Oskar Sebald, Siegmund Seybold, Georg Philippi, Arno Wörz (eds.): The fern and flowering plants of Baden-Württemberg . Volume 8: Special part (Spermatophyta, subclasses Commelinidae part 2, Arecidae, Liliidae part 2): Juncaceae to Orchidaceae . Eugen Ulmer, Stuttgart 1998, ISBN 3-8001-3359-8 .
  • Dietmar Aichele, Heinz-Werner Schwegler: The flowering plants of Central Europe , Franckh-Kosmos-Verlag, 2nd revised edition 1994, 2000, Volume 5, ISBN 3-440-08048-X

supporting documents

  1. ^ Adolf Riechelmann: The orchids of the Franconian Switzerland. Palm & Enke, Erlangen 2011, ISBN 978-3-7896-1701-0 , p. 272 ​​ff.
  2. ^ Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . 8th edition. Verlag Eugen Ulmer, Stuttgart 2001, ISBN 3-8001-3131-5 . Page 274.
  3. a b Helmut Baumann , Siegfried Künkele : Orchidaceae . In: Oskar Sebald u. a .: The fern and flowering plants of Baden-Württemberg. 1st edition Volume 8, page 331. Verlag Eugen Ulmer, Stuttgart 1998. ISBN 3-8001-3359-8
  4. ^ Helmut Baumann , Siegfried Künkele and Richard Lorenz: Orchids in Europe with adjacent areas . Verlag Eugen Ulmer, Stuttgart, 2006. ISBN 978-3-8001-4162-3 . Page 301.

See also

Web links

Commons : Herbst-Drehwurz ( Spiranthes spiralis )  - Album with pictures, videos and audio files

Distribution maps

Regional links