Saturday, April 26, 2008

Tropical plant - Mimosa Pudica - Sensitive plant

This entry is about a special plant called Mimosa Pudica that is able to folds its leaves when touched or exposed to heat. When touched, the leaves folds as if it alive.

Common name for this plant is "Sensitive plant" or "Shy plant". In Malaysia, it is called "Semalu". Based on the common name, the impression is that the plant is "shy" because of its folding capability when touched.

Mimosa Pudica shrub

Mimosa Pudica bloom

More about Mimosa

Mimosa is a genus of about 400 species of herbs and shrubs, in the subfamily Mimosoideae of the legume family Fabaceae. The most curious plant in the genus is Mimosa pudica because of the way it folds its leaves when touched or exposed to heat; many others also fold their leaves in the evening. It is native to southern Mexico, Uruguay and Central America but is widely cultivated elsewhere for its curiosity value, both as an indoor plant in temperate areas, and outdoors in the tropics. Outdoor cultivation has led to weedy invasion in some areas, notably Hawaii.

Members of this genus are among the few plants capable of rapid movement; examples outside of Mimosa include the Telegraph plant, and the Venus Flytrap.

The genus Mimosa has had a tortuous history, having gone through periods of splitting and lumping, ultimately accumulating over 3,000 names, many of which have either been synonymized under other species or transferred to other genera. In part due to these changing circumscriptions, the name "Mimosa" has also been applied to several other related species with similar pinnate or bipinnate leaves but now classified in other genera, most commonly to Albizia julibrissin (Silk Tree) and Acacia dealbata (Silver Wattle).

The plant can be found in many parts of Bengal, where it is known as lajjabati (literally a shy female).

Mimosa Pudica

Mimosa pudica is well known for its rapid plant movement. In the evening the leaflets will fold together and the whole leaf droops downward. It then re-opens at sunrise. This type of motion has been termed nyctinastic movement. The leaves also close up under various other stimuli, such as touching, warming, or shaking. The stimulus can also be transmitted to neighbouring leaves. These types of movements have been termed seismonastic movements. The movement is caused by "a rapid loss of pressure in strategically situated cells that cause the leaves to droop right before one’s eyes". This characteristic is quite common within the Mimosaceae family.

For more hi-resolution photos, check out my Flickr Gallery: Plant

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