(Also known as: Mimosa invisa)
Common names (selected): English: Giant sensitive plant, creeping sensitive plant, nila grass; Chinese: 美洲含羞草 (American mimosa); Fiji: co gadrogadro, wa ngandrongandro levu, wa ngandrongandro ni wa ngalelevu; French: grande sensitive, sensitive gèante; Palau: mechiuaiuu; Samoa: la'au fefe palagi; Saipan: singbiguin sasa
Description: Annual, fast growing, woody shrub forming low, tangled masses or climbing on other vegetation with the aid of its sharp spiny stems. Its flowers are clustered fluffy pink balls. Its seeds can lay dormant for up to 50 years.
Native regions and distribution: Native to Central and South America and the Caribbean, M. diplotricha has now become widespread throughout south and south-east Asia, the Pacific islands, northern Australia and parts of Africa.
Urban habitat: M. diplotricha commonly grows in crops, plantations and pastures, as well as on disturbed moist wastelands and along roadsides, drains and watercourses. It can tolerate a wide range of soil conditions. It is regarded as being one of the 76 worst agricultural weeds of the world, causing heavy damage in crops like sugar cane, coconut, rubber, cassava, tea, pineapple and upland rice.
Ecological functions: Habitat for crickets and grasshoppers. Source of pollen for Italian honey bees in the Philippines. Young shoots are eaten by water buffalo.
History/human uses: Mimosa is from the Greek mimikos which means 'to mimic' or 'counterfeit', though the Latin mimus and the feminine suffix -osa which means abounding in, refers to several flowers masquerading as a single flower. M. diplotricha was introduced to Taiwan in 1965 as an ornamental and the first herbarium specimen was collected in 1976. It was probably accidentally introduced into South-East Asia in the 19th Century. In the early 20th Century it was taken into cultivation in Java and Sumatra and from there to other countries in South-East Asia. M. diplotricha has a woody taproot with nitrogen-fixing nodules on the laterals and due to this and its tolerance for light shade, it was frequently used as a cover crop and soil renovator in plantations, adding nitrogen and organic matter, reducing erosion. It is used as a green manure under coconuts in India, tobacco in Sumatra, tea in Indonesia, coffee in the Côte d'Ivoire, cocoa in Cameroon, rubber in Sri Lanka, and maize in Thailand. Thick growth of M. diplotricha prevents the regeneration, reproduction and growth of indigenous species in all infested areas. All parts of the plant are toxic to herbivores if ingested. It produces a toxin (mimosin - a non-protein amino acid), which can cause vascular endothelial damage, necrosis of the heart and liver and anemia in cattle.