Calotropis

Life-forms

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Cladus: Asterids
Cladus: Lamiids
Ordo: Gentianales

Familia: Apocynaceae
Subfamilia: Asclepiadoideae
Tribus: Asclepiadeae
Subtribus: Asclepiadinae
Genus: Calotropis
Species: C. acia – C. gigantea – C. procera
Name

Calotropis R.Br., Mem. Wern. Nat. Hist. Soc. 1: 39 (preprint). 1810.
Lectotype species: Calotropis procera (Aiton) Dryand., vide Bullock (1957)

Synonyms

Homotypic
Madorius Rumph. ex Kuntze, Rev. Gen. 421. 1891.

Notes

Calotropis Post & Kuntze (1903) = Galega L.

References

Brown, R. 1810. Mem. Wern. Nat. Hist. Soc. 1: 39 (preprint).
Bullock, A.A. (1957) ING card 03911.
Tropicos.org 2009. Calotropis. Missouri Botanical Garden. Published on the internet. Accessed: 24 Feb 2009.
International Plant Names Index. 2009. Calotropis. Published online. Accessed: 24 Febr 2009.

Vernacular names
suomi: Madarit
svenska: Kronbusksläktet

Calotropis is a genus of flowering plants in the family Apocynaceae, first described as a genus in 1810. It is native to southern Asia and North Africa.[2]

They are commonly known as milkweeds because of the latex they produce. Calotropis species are considered common weeds in some parts of the world. The flowers are fragrant and are often used in making floral tassels in some mainland Southeast Asian cultures. Fibers of these plants are called madar or mader. Calotropis species are usually found in abandoned farmland.

Botanical description
Calotropis procera

Calotropis gigantea and C. procera are the two most common species in the genus. Calotropis gigantea grows to a height of 8 to 10 ft (2.4 to 3.0 m) while C. procera grows to about 3 to 6 ft (0.91 to 1.83 m). The leaves are sessile and sub-sessile, opposite, ovate, cordate at the base. The flowers are about 1.5 to 2 in (3.8 to 5.1 cm) in size, with umbellate lateral cymes and are colored white to pink and are fragrant in case of C. procera while the flowers of C. gigantea are without any fragrance and are white to purple colored, but in rarer cases are also light green-yellow or white. The seeds are compressed, broadly ovoid, with a tufted micropylar coma of long silky hair.[3]

Pollination is performed by bees (entomophily) by the following mechanism:

The stigmas and androecia are fused to form a gynostegium. The pollen are enclosed in pollinia (a coherent mass of pollen grains). The pollinia are attached to an adhesive glandular disc at the stigmatic angle. When a bee lands on one of these, the disc adheres to its legs, and the pollinium is detached from the flower when the bee flies away. When the bee visits another flower, the flower is pollinated by the adhering pollinium on the bee.

Species[4]

Calotropis acia Buch.-Ham. - India
Calotropis gigantea (L.) Dryand. - China, Indian Subcontinent, Southeast Asia
Calotropis procera (Aiton) Dryand. - China, Indian Subcontinent, Southeast Asia, Middle East, North Africa

formerly included[4]

Calotropis sussuela, synonym of Hoya imperialis
Toxicity

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The milky exudation from the plant is a corrosive poison. Calotropis species are poisonous plants; calotropin, a compound in the latex, is more toxic than strychnine.[5] Calotropin is similar in structure to two cardiac glycosides which are responsible for the cytotoxicity of Apocynum cannabinum. Extracts from the flowers of Calotropis procera have shown strong cytotoxic activity. The extracts are also harmful to the eyes.

Cattle often stay away from the plants because of their unpleasant taste and their content of cardiac glycosides.
Cultural significance

The flowers of the plant are offered to the Hindu deities Shiva, Ganesha, Shani Dev and Hanuman.
References

"Calotropis R. Br". Germplasm Resources Information Network. United States Department of Agriculture. 2003-03-13. Archived from the original on 2012-10-06. Retrieved 2010-06-26.
Flora of China Vol. 16 Page 202 牛角瓜属 niu jiao gua shu Calotropis R. Brown, Mem. Wern. Nat. Hist. Soc. 1: 39. 1810
"Calotropis gigantea: Useful Weed". NewCROP. Purdue University.
The Plant List, genus Calotropis
S. Morris Kupchan; John R. Knox; John E. Kelsey; J. A. Saenz Renauld (25 December 1964). "Calotropin, a Cytotoxic Principle Isolated from Asclepias curassavica L". Science. 146 (3652): 1685–6. Bibcode:1964Sci...146.1685K. doi:10.1126/science.146.3652.1685. PMID 14224519. S2CID 31489685.