Clover fern

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Clover fern
Clover fern (Marsilea quadrifolia), in the lower half of the picture. The pill fern (Pilularia globulifera) is shown above.

Clover fern ( Marsilea quadrifolia ), in the lower half of the picture. The pill fern ( Pilularia globulifera ) is shown above.

Systematics
Ferns
Class : True ferns (Polypodiopsida)
Order : Floating ferns (Salviniales)
Family : Clover family (Marsileaceae)
Genre : Clover ferns ( Marsilea )
Type : Clover fern
Scientific name
Marsilea quadrifolia
L.

The clover fern ( Marsilea quadrifolia ), also known as the four-leaf clover , is a species of clover ferns within the family of the clover ferns (Marsileaceae).

description

The fern clover is a perennial plant and forms thin, hairy rhizomes , from which roots and leaves arise at each node . The rhizomes are creeping and form lawns. The stature height is 5 to 20 cm. The leaves have long stalks and resemble a four-leaf clover, but consist of two opposite, close-together pairs of leaves. The leaflets are broadly wedge-shaped and folded in the bud position . The leaf veins are fan-shaped and closed.

The juvenile, underwater, swimming and land leaves look very similar, but only the latter form spore capsules. These are bean-shaped and are two to four at the base of the petiole. The spores ripen in September and October.

The number of chromosomes is 2n = 40, less often 32 or 100–140.

ecology

The sporocarpies of the clover fern are only formed in areas that have fallen dry. The plant is very sensitive to changes in water level. When the water level rises, the old leaves die (due to the lack of intercalary growth, the petioles cannot stretch) and new leaves are formed.

The clover ferns are the only genus of ferns in which the leaves perform sleep movements; During the day the pinnate sections of the leaf blade lie in one plane, in the evening and at night they hang down.

Occurrence and endangerment

Clover fern

The clover fern is a Eurasian-sub-Mediterranean-subcontinental flora element . It occurs scattered throughout Eurasia, from Europe to western Siberia to Kashmir, northern China and Japan. It was introduced into North America. The northern border in Europe runs from the Loire region through Alsace, the Upper Rhine region, the Czech Republic and Poland.

In Germany the species is considered extinct. The last autochthonous deposit was destroyed in the 1960s. In Baden-Württemberg there is a possible spontaneous settlement. The species was also anointed in various places . In Austria the species is only found in Styria, in the other federal states it is extinct or lost. In Switzerland, the species is endangered nationwide and regionally extinct. Only a few sites are known.

The clover fern grows in loose lawns or in loose herds in shallow (up to 40 cm deep) water or on dry mud, on lighter, moderately nutrient-rich, base-rich, moderately calcareous to low-calcium, basic to slightly acidic areas on clay or silt soils Open places in clay pits or in pig pastures, in the bank area temporarily dry ponds. In the water it is associated with Chara spec. and with Najas minor ; it lives on dry mud with Eleocharis acicularis , Limosella aquatica or with Cyperus fuscus . As the heat-loving plant, he does not rise above the colline altitude level . It occurs in societies of the Eleocharition acicularis and probably also in those of the Nanocyperion.

At the European level, the clover fern is listed by the European Union in the Habitats Directive , Annex II and IV and is therefore one of the strictly protected animal and plant species of Community interest, for whose conservation special protected areas must be designated.

Taxonomy

The scientific name Marsilea quadrifolia was first published in 1753 by Carl von Linné in Species Plantarum .

literature

  • Siegmund Seybold (Ed.): Schmeil-Fitschen interactive . CD-ROM, version 1.1. Quelle & Meyer, Wiebelsheim 2002, ISBN 3-494-01327-6 .

Individual evidence

  1. ↑ a b 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. 87 .
  2. ↑ a b c d Oskar Sebald, Siegmund Seybold, Georg Philippi (ed.): The fern and flowering plants of Baden-Württemberg . 2nd, supplemented edition. tape 1 : General Part, Special Part (Pteridophyta, Spermatophyta): Lycopodiaceae to Plumbaginaceae . Eugen Ulmer, Stuttgart (Hohenheim) 1993, ISBN 3-8001-3322-9 .
  3. ↑ Christoph Käsermann: Marsilea quadrifolia L. - Kleefarn - Marsileaceae. In: Christoph Käsermann, Daniel M. Moser (Eds.): Information sheets on species protection - flowering plants and ferns (as of October 1999). Federal Office for the Environment, Forests and Landscape, Bern 1999, pp. 196–197 (PDF file) .
  4. ^ A b 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 .
  5. ^ Marsilea quadrifolia. In: Info Flora (the national data and information center for the Swiss flora) , accessed on May 14, 2015.
  6. ↑ Council Directive 92/43 / EEC of May 21, 1992 on the conservation of natural habitats and wild fauna and flora (Habitats Directive) in the consolidated version of July 1, 2013 , Annex II. In: OJ. L 206 of July 22, 1992, p. 33 ( Marsilea quadrifolia ).
  7. ↑ Carl von Linné: Species Plantarum. Volume 2, Lars Salvius, Stockholm 1753, p. 1099 ( digitizedhttp: //vorlage_digitalisat.test/1%3Dhttp%3A%2F%2Fwww.biodiversitylibrary.org%2Fopenurl%3Fpid%3Dtitle%3A669%26volume%3D2%26issue%3D%26spage%3D1099%26date%3D1753~GB%3D~ IA% 3D ~ MDZ% 3D% 0A ~ SZ% 3D ~ double-sided% 3D ~ LT% 3D ~ PUR% 3D ).

Web links

Commons : Vierblättriger Kleefarn ( Marsilea quadrifolia )  - Album with pictures, videos and audio files