Wood sorrel

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Wood sorrel
Wood sorrel (Oxalis acetosella), illustration

Wood sorrel ( Oxalis acetosella ), illustration

Systematics
Rosids
Eurosiden I
Order : Wood sorrel (Oxalidales)
Family : Wood sorrel family (Oxalidaceae)
Genre : Wood sorrel ( Oxalis )
Type : Wood sorrel
Scientific name
Oxalis acetosella
L.
Macro shot of a wood sorrel blossom
Wood sorrel
Wood sorrel in late summer
folded down leaves

Wood sorrel ( Oxalis acetosella ) is a species of wood sorrel ( Oxalis ) belonging to the wood sorrel family (Oxalidaceae).

The wood sorrel is a relic species ; most of the approximately 800 oxalis species are tropical or subtropical.

Features and ecology

The wood sorrel is a perennial herbaceous plant that reaches heights of 5 to 15 cm. As a survival organ, it forms a short, underground rhizome and a richly branched, fleshy taproot. The long-stalked leaf is three-part, clover-like pinnate. The leaves are a bit fleshy, grass-green and have a sour taste. The three leaves are inverted heart-shaped.

A single-flowered stem is formed. The long-stalked, delicate appearing, five-fold flowers are radial symmetry with double perianth . The five sepals are green. The five petals have a white or pale pink color with a clearly visible reddish-purple vein. A yellowish spot can be seen at the base of the petals. There are two circles with five white stamens each. On the elongated ovary has five pens. The wood sorrel blooms from April to June.

Five-way capsule fruits are formed.

It is the most shade-friendly native plant species that can still grow with a minimum of 1/160 of daylight. When exposed to strong sunlight, the plant changes the position of its leaves by folding the pinnate leaves down. This protects the wood sorrel from water loss as a result of transpiration, as the stomata on the undersides of the leaves lie against one another.

When the air humidity is high, water separation ( guttation ) is actively carried out. The wood sorrel has two types of flowers:

  • A bell-shaped one that is accessible to bees and bumblebees. This is rare due to the mostly shady locations and is usually formed with the first spring blossoms. The seed development is rather low here. The violet veins and the yellowish spots on the petals favor pollination. As sap marks, they lure the insects to the base of the petals, where sweet nectar is offered.
  • A closed flower in which self-pollination ( Kleistogamy ) takes place. This form is usually developed in the later, short-stemmed flowers that bloom near the ground. Compared to the bell-shaped flower, significantly more seeds are formed.

The fruits are nutty and triangular. A centrifugal mechanism encourages the seeds to spread. The germination capacity is given immediately after ripening and depends on moisture.

The early bloomer draws the necessary reserve substances from its creeping rhizome as well as from the thickened leaf base of its winter-green, fleshy lower leaves. After the upper leaves have died, the leaf bases remain as thick storage scales on the rhizome.

The plant can fold its leaves together like an umbrella via joints that sit at the transition from the leaflet to the stem and react to changes in cell pressure. This can be observed, for example, with strong vibrations, overexposure, cooler temperatures and in the dark. A turgor decrease on the underside of the joint and the upper side of the ribs causes this folding position. It is controlled via turgorine (chemical signal substances), which can also be found in mimosas , among other things . Lenticular cells on the top of the leaf presumably act as measuring devices.

The wood sorrel is a juice pressure spreader that ejects its seeds at 16 to 17 bar.

An endotrophic mycorrhiza is present. The wood sorrel has only shallow roots up to 15 centimeters deep.

The species has chromosome number 2n = 22.

Occurrence

The wood sorrel is common in the northern and temperate latitudes of Europe and Asia .

Wood sorrel grows on acidic forest soils in extremely shady and fresh to moist places in mixed deciduous and coniferous forests. He can also endure deeper shadows. Plant sociology : In Central Europe it has its main focus in the Galio-Abietion and in montane Fagion societies. It also occurs in other Fagetalia - as well as in Betulo-Adenostyletea - or in herb-rich Vaccinio-Piceetalia societies. In the Alps it occurs at altitudes of up to 1940 meters. In the Allgäu Alps, it thrives at the Schnurschrofen southwest of Tannheim in Tyrol at 1890 m above sea level.

ingredients

Primary (acid) potassium oxalate = potassium dioxalate = Sal Acetosellae = clover salt . Oxalic acid is also contained in small quantities . In the rhizome there is a small amount of an anthraquinone derivative (substance similar to chrysophanic acid). The seed contains fatty oil.

use

The chopped leaves can be used to make soups, sauces and salads. Only small amounts should be used because wood sorrel is toxic in larger amounts.

The wood sorrel was collected in the Black Forest until the 19th century to prepare sour clover salt Sal Acetosellae or Acidum oxalicum , which was used to polish marble and other limestones, as well as to remove certain deposits on natural stone and discoloration of oak wood . In these contexts, the term bitter clover salt was incorrectly used .

If wood sorrel occurs in abundance, it can be toxic to livestock. Poisoning rarely occurs in humans, and only when consumed in large quantities.

literature

Individual evidence

  1. ↑ Ruprecht Düll , Herfried Kutzelnigg : Pocket dictionary of plants in Germany. A botanical-ecological excursion companion to the most important species. 6th, completely revised edition. Quelle & Meyer, Wiebelsheim 2005, ISBN 3-494-01397-7 , p. 341.
  2. ↑ Düll, Ruprecht: Botanical-ecological excursion pocket book: the most important facts about the biology of selected wild-growing and cultivated fern and flowering plants in Germany ; 5. revised and additional ed., Quelle and Meyer, Wiesbaden 1994.
  3. ↑ a b c Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . 8th edition. Verlag Eugen Ulmer, Stuttgart 2001, ISBN 3-8001-3131-5 . Page 622.
  4. ↑ Erhard Dörr, Wolfgang Lippert: Flora of the Allgäu and its surroundings. Volume 2. IHW, Eching 2004, ISBN 3-930167-61-1 , p. 174.

Web links

Commons : Wood sorrel ( Oxalis acetosella )  - Album with pictures, videos and audio files