The Brennnesseln (Urtica) forms a kind in the family of the (Urticaceae) and belongs thus to the Bedecktsamern (Magnoliophyta). In Central Europe about 45 kinds of this kind are to be found.

Botani characteristics

Description

Brennnesseln are krautige plants and reach, depending upon kind, location and nutrient situation, stature heights of ten to 250 centimeters. Their is mostly normally and with burning as well as, kind-dependently, Borstenhaaren occupied.

, The oblong sheets likewise behaarten on the top side are centimeters long and of low-greener color, forward intensified, at the beginning and at the edge usually roughly sawed up to eight. Within some kinds it gives however also to representative with glattrandigen sheets, this characteristic approximately with the pill Brennnessel (And pilulifera) rezessiv is left. These glattrandigen plants resemble the Majoran and particularly were in 18. Century as "Spanish Majoran "center of some crude jokes. With most kinds the sheets are arranged cross against constant and possess frequently small in the Blattachseln. Here also the blooms stand.

The oblong, tiny to small, inconspicuous blooms, in Rispen, are from whiter, occasionally pale-violet color and attract small insects than The blooms are predominantly in-sexually, contained thus either the male Staubbeutel or a female Fruchtknoten. Male and female blooms can have to be found on a plant = or on different plants = The bloom consists usually of four bloom cladding sheets (rarer also two to five can occur) and a just as large number of The Fruchtknoten lies central in the bloom and by only one Fruchtblatt is formed.

The Vermehrung is made predominantly vegetativy by Rhizome, otherwise are the plants wind-dusting, if the male cladding sheets open, snap their out; like an explosion a cloud is hurled by Pollen into air. The wind transfers afterwards the Pollen to the female blooms.

The oval of elliptical fruits coming out from it are large up to two millimeters and as are designated.

Fuel hair

The Brennnesseln is well-known and unpopularly because of the painful Quaddeln (swelling), which develop on the skin after contact of the fuel hair.

The plant developed these fuel hair as protective mechanism under the sheets and at the There is long tubes, whose walls are in the top by stored silicic acid hard and brittle like glass. The lower, more flexible end swelled strongly and into a cell cup encompassed, which consists point of a directed sideways, under which by the here very thin wall a kind is present break section. Brennnesseln can be touched driveless if one the plant from bottom to top re-paint over. Otherwise the can break off during an easy contact and leaves a diagonal, sharp location of fracture, equal some medical With contact the villi bores itself into the skin of the victim, in which then the ant-acid contents of (methane acid) pour out from it into the wound, which causes then burning pain and often also inflammations.

Further active substances are Serotonin, histamine, acetyl choline and sodium formate. A ten-millionth gram of this fuel liquid is already sufficient, in order to obtain the well-known effect.

Histamine extends the blood capillaries and can reactions cause, which resemble allergischen reactions (these are caused among other things by release of body-own histamine).

Acetyl choline is also the carrier substance of many nerve endings and responsible for the burning pain.

The Brennnessel gave also its name to a allergischen reaction of the skin, the Nesselsucht or Urtikaria. Exactly as with a provoking by Brennnesseln it causes itching Quaddeln. Here the histamine from mast cells of the skin is set free.

Spreading

The Brennnesseln is almost world-wide common, it is not particularly fastidious, it is missing only in Permafrostgebieten. Individual kinds are not to be found everywhere, the large Brennnessel (Urtica dioica) for example are missing in the Tropics, in South Africa, on the Balearen and on Crete.

The large Brennnessel seems in particular in stauden and to persistent weeds corridors, in addition, in break and It is settled a pointer plant for high nitrogen occurrences in the soil and as pioneer plant very fast unbewachsene surfaces. If the plant were only established, which becomes not extreme nutrients the order and it drying, the Brennnessel has no more problems to maintain ground over many years (up to 20 years) against all other plants. Many kinds live also as soil plants, primarily in tropical and subtropical forests.

Butterfly pasture

For the crawler-type vehicles of approximately 50 kinds of butterfly the Brennnesseln is a fodder plant. The kinds of butterfly admiral, Tagpfauenauge, small fox (also as Nesselfalter admits), silver-grey Nessel dark grey Nessel Brennnessel (scientific: Hypena obesalis) and the land small card are dependent for it even on the Brennnessel, other plants are possible for these kinds not (Monophagie). Nevertheless these kinds of butterfly seem to make itself hardly mutually competition, because they prefer in each case different stature sorts of the Brennnessel or are relatively rare.

• The crawler-type vehicles of the small fox are to be found in dry and sunny places.
• The Tagpfauenauge likes it also sunny, but nevertheless humid and preferentially therefore places at waters.

Both kinds need besides larger

• The admiral against it is satisfied already with accumulations of some fewer plants and prefers rather "miserable "Brennnesseln.
• The land small card selects itself the shadiest stature places of the Brennnessel, the often large and close existence in river and brook-accompanying

On nearly each Brennnessel seizing marks of individual insects are to be seen. These must have developed a strategy, with which they deal the fuel hair. They eat around the hair and prefer thereby the ways along the leaf veins and from the page margins, since no fuel hair is there. Favourably for the insects: The "poison" does not penetrate from the point, if the hair is corroded down at the root.

Articles in category "Brennnesseln"

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