Calotropis

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Calotropis
Oscher (Calotropis procera)

Oscher ( Calotropis procera )

Systematics
Order : Enzianartige (Gentianales)
Family : Dog poison family (Apocynaceae)
Subfamily : Silk plants (Asclepiadoideae)
Tribe : Asclepiadeae
Sub tribus : Asclepiadinae
Genre : Calotropis
Scientific name
Calotropis
R.Br.
Crownflower ( Calotropis gigantea )

The Calotropis , seldom called keel crowns, are a genus of plants in the subfamily of the silk plants (Asclepiadoideae) within the family of dog poison plants (Apocynaceae). There are three types of Calotropis .

Occurrence

The natural distribution areas are in Africa and Asia. The species are wild in many arid areas of the tropics. They thrive on roadsides, savannahs and unwooded landscapes at low and medium altitudes.

description

Two species of Calotropis are richly branched shrubs or small trees and Calotropis acia is an upright herbaceous perennial plant . They reach heights of 1 to 6 m. They contain white milky juice . The bark of the twigs is smooth or initially hairy. The leaves are arranged opposite each other on the branches. The simple leaves are stalked in Calotropis acia, sessile in the other species. The leathery or fleshy leaf blade is 9 to 28 cm long and 5 to 15 cm wide. The leaf margins are smooth or wavy. The upper side of the leaf is smooth and the underside of the leaf is smooth or tomentose.

Three to 17 flowers stand together in simple or branched, complicated inflorescences . The flower stalk is hairy yellow. The hermaphrodite, radially symmetrical flowers are five-fold. The five free sepals have at most a quarter of the length of the petals, are egg-shaped and end with a point. The five green, white, cream-colored or purple petals are 10 to 18 mm long, egg-shaped and only fused at the base, they are sometimes colored differently on the inside than on the outside. There is only one circle with five stamens . Two carpels are two free upper permanent ovary deformed, the two punches are fused up to a common five-edged scar. The stamens are fused with each other and the two pistils to form a column (a gynostegium ).

Two dry follicles are formed per flower . In Calotropis procera they together form an apple-like fruit that has a diameter of about 70 mm and a length of 100 to 120 mm, in the other species they are in a 180 °. Each follicle contains around 100 to 150 seeds. The seeds are 7 to 8 mm long and 4 to 5 mm in diameter. They have an approximately 30 mm long tuft of white, silky hair as a flight organ.

Systematics

A synonym for Calotropis R.Br. is Madorius Rumph. ex Kuntze .

There are three species in the genus Calotropis :

  • Calotropis acia Buch.-Ham. : It occurs from the Himalayas to Assam and in northeastern India.
  • Crown flower or Madar shrub ( Calotropis gigantea (L.) R.Br. ): It occurs from southern China to tropical Asia.
  • Oscher , Oscherstrauch or Fettblattbaum ( Calotropis procera (Aiton) WTAiton , Syn . : Asclepias procera Aiton , Asclepias gigantea Jacq. Non L. ): It occurs in Macaronesia and from northern and tropical Africa to Indochina.

photos

Oscher ( Calotropis procera ):

literature

Individual evidence

  1. ↑ a b c Rafaël Govaerts (Ed.): Calotropis - World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew. Last accessed on November 4, 2017.

Web links

Commons : Calotropis  - collection of images, videos and audio files