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(L.) W.T.Aiton 1811 not (L.) R. Br. 1811
Calotropis gigantea (Crown flower) is a species of Calotropis native to Cambodia, Indonesia, Malaysia, Philippines, Thailand, Sri Lanka, India, China, Pakistan, Nepal, and tropical Africa.
It is a large shrub growing to 4 m (13 ft) tall. It has clusters of waxy flowers that are either white or lavender in color. Each flower consists of five pointed petals and a small "crown" rising from the center which holds the stamens. The aestivation found in calotropis is valvate i.e. sepals or petals in a whorl just touch one another at the margin, without overlapping. The plant has oval, light green leaves and milky stem. The latex of Calotropis gigantea contains cardiac glycosides, fatty acids, and calcium oxalate.
This plant plays host to a variety of insects and butterflies. It is the host plant for Hawaii's non-migratory monarch butterflies. Calotropis is an example of entomophily pollination (pollination by insects) and pollination is achieved with the help of bees. In Calotropis, gynostegium is present (formed by the fusion of stigma and androecium). The pollen are arranged in a structure named pollinia which are attached to a glandular, adhesive disc at the stigmatic angle (Translator Mechanism). These sticky discs get attached to the legs of visiting bees so that pollinia are pulled out when the bee moves away. When such a bee visits another flower, this flower gets pollinated by the sticky pollinium.
The flowers last long, and in Thailand they are used in various floral arrangements. They were favored by the Hawaiian Queen Liliuokalani, who considered them a symbol of royalty and wore them strung into leis. While in Cambodia, they are used in funerals to decorate the urn or sarcophagus and the interior of the house holding the funeral. The fruit is a follicle and when dry, seed dispersal is by wind. In Indonesia its flowers are called widuri.
Calotropis yields a durable fiber (commercially known as Bowstring of India) useful for ropes, carpets, fishing nets, and sewing thread. Floss, obtained from seeds, is used for stuffing purposes. Fermented mixture of Calotropis and salt is used to remove the hair from goat skins for production of "nari leather" and of sheep skins to make leather which is much used for inexpensive book-binding.[full citation needed] Fungicidal and insecticidal properties of Calotropis have been reported.[full citation needed]
In India, the plant is common in the compounds of temples and is known as Madar in Hindi: मदार. Its leaf (Marathi: rui) is one of the five leaves used in the Panch Pallava, a ritual assortment of five different leaves used as a totem by the Maratha culture in India.
It is known as වරා (waraa) in Sinhala, Aakonda in Bengali, and Erukku (എരുക്ക്) in Malayalam.
Allelopathic effects of Calotropis on different agricultural crops have been well studied. Extracts of different plant parts such as root, stem, and leaf affect germination and seedling vigor of many agricultural crops.[full citation needed][full citation needed] However, extracts of Calotropis failed to produce any detrimental effects on weeds such as Chenopodium album, Melilotus alba, Melilotus indica, Sphaeranthus indicus, and Phalaris minor.[full citation needed]
Calotropis is a poisonous plant. The active principles are uscharin, calotoxin, calactin, and calotropin. The leaves and stem when incised yield thick milky juice. It is used as an arrow poison, cattle poison (see also Sutari), rarely for suicide and homicide and mostly an accidental poison.
The milky latex sap of Calotropis gigantea is a known cause of toxic keratoconjunctivitis and reversible vision loss. Crownflower keratitis is a rare condition and is usually the result of accidental ocular exposure to the sap. During the process of making a Hawaiian lei flower necklace, touching the sap and then touching the ocular surface may result in Crownflower keratitis. Damage (poisoning) of the cornea endothelium results in corneal stromal edema and decreased visual acuity. Although there is some permanent damage to the corneal endothelium with decreased endothelial cell count and irregular shape, the remaining corneal endothelial cells usually recover with complete resolution of the corneal edema and a return to normal visual acuity. The condition is usually self-limited and resolves faster with topical steroids. The clinical course of this condition suggests that Calotropis is paradoxically relatively nontoxic to corneal epithelium and highly toxic to corneal endothelium. The painless clinical course may be related to anesthetic properties of Calotropis latex and relatively minor epithelial injury.
Signs and symptoms
Applied to the skin, it causes redness and vesication. When taken orally, the juice produces an acrid, bitter taste and burning pain in throat and stomach, salivation, stomatitis, vomiting, diarrhea, dilated pupils, tetanic convulsions, collapse and death. The fatal period is 6 to 12 hours. Treatment includes stomach wash, demulcents, and symptomatic treatment.[medical citation needed]
Mosquito controlling property
C. gigantea is reported to exhibit mosquito controlling properties against Culex gelidus and Culex tritaeniorhynchus mosquitoes which serves as vectors for Japanese encephalitis. The aqueous extract of the C. gigantea leaves demonstrated significant larvicidal, repellent and ovicidal activity.
In the Paushya chapter of the Adi Parva portion of the Indian epic Mahabharata, a disciple of the rishi Ayoda-Daumya named Upamanya goes blind by eating the leaves of the plant which in Sanskrit is called "Arka".
However, in India, among the general public, it is the belief that, Akada (Arka) is a poisonous plant and can make people intoxicated. Lord Shiva is offered Akada along with Dhatura (extremely toxic) flowers on auspicious days.
|Wikimedia Commons has media related to Calotropis gigantea.|
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- Singh et al. 1996
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- Indian Trees
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- Hani S. Al-Mezaine, Ali A. Al-Rajhi, Abdullah Al-Assiri, Michael D. Wagoner, Calotropis procera (ushaar) keratitis, American Journal of Ophthalmology, Volume 139, Issue 1, January 2005, Pages 199-202
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- PIER - Calotropis gigantea
- Flowers of India - Crown flower
- Purdue University: Center for New Crops & Plant Products - Crown flower
- Dressler, S.; Schmidt, M. & Zizka, G. (2014). "Calotropis gigantea". African plants – a Photo Guide. Frankfurt/Main: Forschungsinstitut Senckenberg.