Mimosa

Mimosa is a genus of about 400 species of herbs and shrubs, in the subfamily Mimosoideae of the legume family Fabaceae. The generic name is derived from the Greek word μιμος (mimos), an "actor" or "mime," and the feminine suffix -osa, "resembling", suggesting its 'sensitive leaves' which seem to 'mimic conscious life'.
Two species in the genus are especially notable. One is Mimosa pudica, because of the way it folds its leaves when touched or exposed to heat. It is native to southern Central and South America but is widely cultivated elsewhere for its curiosity value, both as a houseplant in temperate areas, and outdoors in the tropics. Outdoor cultivation has led to weedy invasion in some areas, notably Hawaii. The other is Mimosa tenuiflora, which is best known for its use in shamanic ayahuasca brews due to the psychedelic drug dimethyltryptamine found in its root bark.

The taxonomy of the genus Mimosa has had a torturous 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 are now classified in other genera. The most common examples of this are Albizia julibrissin (silk tree) and Acacia dealbata (wattle).

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Mimosa pudica leaves closing when touched

Members of this genus are among the few plants capable of rapid movement; examples outside of Mimosa include the telegraph plant, Aldrovanda, some species of Drosera and the famous venus flytrap. The leaves of the Mimosa pudica close quickly when touched. Some mimosas raise their leaves in the day and lower them at night, and experiments done by Jacques d'Ortous de Mairan on mimosas in 1729 provided the first evidence of biological clocks.

Mimosa can be distinguished from the large related genera, Acacia and Albizia, since its flowers have 10 or fewer stamens. Note that, botanically, what appears to be a single globular flower is actually a cluster of many individual ones. Mimosa contains some level of heptanoic acid.

Mimosa diplotricha in Kerala, India

Mimosa hamanta in Hyderabad, India.

Mimosa scabrella in London

There are about 400 species including:

• Mimosa aculeaticarpa Ortega
  • Mimosa aculeaticarpa var. biuncifera Ortega
• Mimosa arenosa (Willd.) Poir.
• Mimosa asperata L.
• Mimosa borealis Gray
• Mimosa casta L.
• Mimosa cupica Gray
• Mimosa ceratonia L.
• Mimosa diplotricha C.Wright ex Sauvalle
• Mimosa distachya Cav.
• Mimosa dysocarpa Benth.
• Mimosa emoryana Benth.
• Mimosa grahamii Gray
• Mimosa hostilis
• Mimosa hystricina (Small ex Britt. et Rose) B.L.Turner
• Mimosa invisa Martius ex Colla
• Mimosa latidens (Small) B.L. Turner
• Mimosa laxiflora Benth.
• Mimosa malacophylla Gray
• Mimosa microphylla Dry.
• Mimosa nuttallii (DC.) B.L. Turner
• Mimosa pellita Kunth ex Willd.
• Mimosa pigra L.
• Mimosa pudica L.
• Mimosa quadrivalvis L.
  • Mimosa quadrivalvis var. hystricina (Small) Barneby
  • Mimosa quadrivalvis var. quadrivalvis L.
• Mimosa roemeriana Scheele
• Mimosa rubicaulis Lam.
• Mimosa rupertiana B.L. Turner
• Mimosa scabrella Benth.
• Mimosa schomburgkii Benth.
• Mimosa somnians
• Mimosa strigillosa Torr. et Gray
• Mimosa tenuiflora (Willd.) Poir. (= Mimosa hostilis)
• Mimosa texana (Gray) Small
• Mimosa turneri Barneby
• Mimosa verrucosa Benth.