The Common sensitive plant or Sensitive plant (Mimosa pudica L.) is a shrub species belonging to the Mimosaceae family.
From a systematic point of view it belongs to:
Species M. pudica.
The terms are synonyms:
– Eburnax pudica (L.) Raf.;
– Mimosa hispidula Kunth;
– Mimosa pudica f. hispidior Benth.;
– Mimosa tetrandra Humb. & Bonpl. ex Willd.;
– Mimosa unijuga Duchass. & Walp.
Within this species, the following varieties and forms are recognized:
– Mimosa pudica var. hispida Brenan;
– Mimosa pudica var. pastoris Barneby;
– Mimosa pudica var. pudica;
– Mimosa pudica var. setosa Brenan;
– Mimosa pudica var. tetrandra (Humb. & Bonpl. ex Willd.) DC.;
– Mimosa pudica var. unijuga (Duchass. & Walp.) Griseb.;
– Mimosa pudica f. glabrior Benth. ex Fawc. & Rendle, 1920;
– Mimosa pudica f. pudica;
The term Mimosa comes from the Greek μῑμησις mímesis imitation: in reference to the Mimosa pudica which, when touched, withdraws as a person would behave.
The specific pudica epithet comes from modest, chaste, withdrawn, demure, from púdeo feeling ashamed: for the leaves that retract and close when touched.
Geographic Distribution and Habitat –
Mimosa pudica is a plant native to Latin America and especially from Central America to northern South America up to the Caribbean).
This species has been introduced and naturalized in numerous other countries of the tropical belt in Africa, Asia and Oceania, sometimes becoming an invasive species.
This taxon is known to occur within a number of protected areas throughout its native range and the seeds were collected and conserved by the Millennium Seed Bank Project as a method of ex situ conservation.
Its habitat is that of farmland, orchards, pastures, mowed areas, roadsides, areas disturbed by construction, wet wastelands, open plantations and grassy groves at elevations from sea level up to 1,300 metres.
It can grow as a single plant or in tangled bushes.
Mimosa pudica is a plant that can grow from annual to perennial and which has a semi-woody stem, whose branches are equipped with thorns, especially those closest to the roots; these tend towards an increasingly woody development as the age of the plant progresses.
The plant forms small shrubs that can reach 1 meter in height, although they commonly do not exceed 15–45 cm.
The leaves are paripinnate, composed of 12-25 pairs of leaflets, with a bright green color.
The flowers are actinomorphic, with a corolla composed of 4 or 5 petals, small and reduced, and with numerous elongated stamens, which form a pink inflorescence, about one centimeter in diameter, with a characteristic feathery appearance.
The fruit is a shaggy pod, about 2 cm long; this contains from 2 to 4 rounded seeds with a diameter of about 2 mm, of a brown colour.
Mimosa pudica is used and harvested in the wild for medicinal use in the areas where it traditionally grows.
It is also grown as a green manure and for soil stabilization, and is also sometimes grown for its uses in folk medicine.
It is also cultivated as an ornamental plant, being appreciated above all for the characteristic of its leaves which fall downwards whenever they are touched.
It is a typical plant of the tropics, but also naturalized in the subtropical regions, where it is found at altitudes of up to 1,300 metres. It grows best in areas where annual daytime temperatures are between 22-28°C, but can tolerate 10-32°C; however it does not tolerate frost.
It prefers an average annual rainfall of between 1,000 and 2,000 mm, but tolerates between 900 and 3,000 mm and a sunny position, but is not very tolerant of shade and adapts well to wetlands with strong winds.
From a pedological point of view, it grows in most soils, including those that are shallow or poor in nutrients. It prefers a pH in the range of 6 – 7, tolerating 5 – 7.5.
It has often become a weed in forest plantations, farmland, orchards and pastures and is likely to become an invasive plant when it grows in dryland field crops, irrigated wetland rice and plantation crops.
The plant can flower all year round and is a fire hazard when dry. Although it is a perennial plant it can also complete its life cycle within 90 days.
This species has a symbiotic relationship with some soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is used by the growing plant, but some can also be used by other plants growing nearby.
If cultivated it must be known that it is a plant that tends to quickly occupy all the space at its disposal, therefore it is important that, if grown in pots, it is given the right space. Indoors as well as outdoors it does not require excessive attention, however it needs frequent irrigation, otherwise the leaves will tend to turn yellow.
From a phytopathological point of view, it does not have many natural enemies and is hardly attacked, also thanks to its particular defensive technique, although exaggerated exposure to the sun can lead to the arrival of the red spider mite and it tolerates soils with stagnant water badly.
Propagation of mimosa pudica is very simple, although slow compared to many other plant species. It is possible to reproduce it by cuttings, directly in the ground seen the semi-woody nature: the rooting will involve a wait of about 4-6 weeks in which the pot must be kept in a humid place, in partial shade, but at the same time warm.
The propagation by seed is also quite easy, extractable from the numerous pods produced by the plant itself and containing on average between three and five seeds; once the pod has been left to dry, it will be sufficient to extract its contents and bury it a few millimeters from the surface. It is advisable to obtain germination, which will take three or four weeks, in small pots and to transplant the new born ones when they have reached 8-10 centimeters in height. During this process it is important to keep the soil well watered and to have good exposure to light, which is not direct or too intense because the plants will be very fragile as soon as they are born. The first leaves, very small and made up of no more than 4-6 parallel leaflets, are already characterized by the strong sensitivity typical of this plant and close when touched and during the night.
To facilitate sowing, a small quantity of almost boiling water can be poured on the seeds (taking care not to cook them) and then immersed for 12 – 24 hours in warm water. By now they should have absorbed the moisture and swelled – if not, carefully nick the seed coat (taking care not to damage the embryo) and soak for a further 12 hours before sowing.
Customs and Traditions –
An immediately evident characteristic of Mimosa pudica is the immediate contraction of its leaves at the slightest tactile stimulus, which also causes the thinnest branches to lower. This movement is called tigmonastia.
The evening and nocturnal movements of the leaves are instead known as nyctinastia, and are a well-described example of a plant circadian rhythm regulated by light. The change of angle of the paripinnate leaves is caused by the change of cellular turgor of the pulvinus, a specialized structure at the base of the petiole; in practice a mechanism caused by osmosis. The diffusion of K+ ions causes the internal solution to be hypertonic with respect to the external one and thus a cellular turgidity is produced. Depending on whether it takes place in the flexor or extensor cells, the leaf fins open or close.
The mechanism is an excellent defense adaptation of the plant against predators which, when the leaves fold, will find themselves in front of an apparently rotten plant, but it is also functional for limiting the loss of useful liquids during hours of excessive heat or for protection from the wind reducing the exposed surface.
As for the uses of this plant, the delicately scented flowers can be crystallized, or used in the preparation of distilled flower water.
An oil similar to soybean oil is obtained from the seed.
In medicinal use it is known in Ayurveda; the root is bitter, acrid, refreshing, vulnerable, as an antidote. It is used in the treatment of biliousness, leprosy, dysentery, vaginal and uterine disorders, inflammation, burning sensation, fatigue, asthma, leukoderma, blood disease, etc.
According to the Unani or Yunani system of medicine (Perso-Arabic traditional medicine practiced in Muslim culture in South Asia and in today’s Central Asia) the root is decisive, alternative, useful in diseases deriving from blood and bile impurities, biliary fevers, hemorrhoids, jaundice, leprosy, etc.
The root is used to control alcoholism.
The leaves are bitter, slightly sudoriferous and tonic.
A tincture of the leaves is given by teetotalers or drunkards to remedy drunkenness.
The semen is emetic.
The plant contains mimosin, and the roots contain tannin, ash, calcium oxalate crystals.
Extracts of the plant have been shown in scientific studies to be moderate diuretics; to depress duodenal contractions similar to atropine sulfone; promote nerve regeneration; and reduce menorrhagia.
Root extracts are said to be a strong emetic.
Other uses include agroforestry.
The plant forms a dense ground cover and has been used to provide ground cover in coconut plantations.
It has been introduced to subtropical and humid areas of Transcaucasia where it is cultivated for erosion control, ground cover and green manure.
The plant has also been identified as having potential for phytoremediation of arsenic polluted areas in Thailand.
Among the recommendations and the dangers associated with this plant we mention that when the thorns on the stem and on the fruit become too hard, they can cause intestinal inflammation in grazing animals.
Also, in large doses, the roots are toxic.
From an ecological point of view, Mimosa pudica is a common plant and not considered threatened or in decline. The plant is classified as “Least Concern” on the IUCN Red List of Threatened Species (2013).
Method of Preparation –
The mimosa pudica is a plant used in some traditional medicines such as the Ayurvedic one, born in India thousands of years ago or the Unani one of the Muslim culture and widespread in southern Asia and in today’s central Asia.
The root is used to control alcoholism.
The leaves are also used, which are bitter, and are slightly sweaty and tonic.
From the leaves a tincture is obtained which is given by abstainers or drunkards to remedy drunkenness.
Finally, it should be noted that the semen is emetic and therefore causes vomiting.
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.
Attention: The pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not in any way represent a medical prescription; we therefore decline all responsibility for their use for curative, aesthetic or food purposes.