last update: 2008-03-02

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Description Appearance Movement Purchase

Description

The name of the mimosa (Mimosa Pudica) comes from "mimic", because it can move it's leaves, and from "shy, retiring", what means "pudica" in latin. The mimosa is fascinating mankind over a very long time. Already before over 2000 years plants were mentioned which react on contact with movement. Until the 19. century one assumed the mimosa has muscles and nerves like animals. At this time further researches were made, in which one discovered the phenomenon of pressure loss in the plant. The mimosa belongs to the pea family (Leguminosa) and derives originally from the tropical part of South America. In fact it is a perennial plant, but as indoor plant it is often treated annual. It is popular as indoor plant because it reacts to exterior impulses, like touch, with folding up the leaves. The folding up happens very fast, but it depends on the strength of the impulse. The mimosa needs approximately 20-30 minutes for re-erecting the leaves. In some cases not only the leaves will fold up but also the entire branch. There are no strong impulses needed for the folding up, already strong wind can cause the reaction. Only the part of the plant in which the impulse occurs will react, not the entire plant. Because of this behaviour the mimosa obtained several nicknames like "don't-touch-me". The mimosa has a day-and-night-cycle, at night the leaves are folded up. Every part of the mimosa is less or more venomous, so one should not consume it.
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Appearance

The mimosa builds long shafts with few leaves, she can reach a height up to 0.5 meters. The shafts hold small thorns, the blooms are globular with a compact core and many hairs coming off. One can compare it with a blowball with a yellow core and purple hairs. The bloom of the mimosa is very short, it only blooms for one day. During anthesis, there is very often a new burgeon which starts to bloom, so the short bloom is not sore. The evening before the bloom begins, one can sight a discolouring of the burgeon, which is green until then. During night, the hairs are developed and the next morning the plant blooms.

Blätter
leaves
Bluete
bloom
Knospe
burgeon
The mimosa can become a very high plant, the one shown here has today a hight of 2,75 m (9 feet).

Mimose

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Movement

The motility of the mimosas is linked up with the so-called " turgor pressure". This means the pressure to the cell wall, which is caused by water absorbed from the surrounding. An important attribute of the turgor movements is the fact, that they are reversible. The plant is able to accomplish moves by changes in the turgor pressure, which are caused by exterior impulses. Until today, one doesn't know in detail how this happens, but it is known that an impulse results in a change of the permeability in certain cells, which allows, together with a higher flexibility of the cell walls and a decrease in turgor pressure, the movement. When a part of the plant recognizes an impulse, it can be forwarded to neighbouring parts. This probably happens by a change of the electric potential and perhaps by a not yet identified chemical transmitter. There are several theories to explain the movement of the mimosa. By folding up the leaves, the mimosa is less attractive for herbivores.
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Purchase

It is often difficult to buy plants, most stores only sell seeds. The reason for this is probably the sensitivity of the mimosa. When you are searching for mimosa, have a look at our forum. There is a thread, which is about buying mimosa. You can ask whether someone knows a merchant in your area, or, if you know where one can buy mimosa, you can post it there to help other mimosa fans.
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