Adenium obesum

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Adenium obesum
Adenium obesum

Adenium obesum

Systematics
Order : Enzianartige (Gentianales)
Family : Dog poison family (Apocynaceae)
Subfamily : Apocynoideae
Tribe : Nerieae
Genre : Desert roses ( adenium )
Type : Adenium obesum
Scientific name
Adenium obesum
( Forssk. ) Roem. & Schult.

Adenium obesum , also known as desert rose , is a species of plant from the dog poison family(Apocynaceae). It is used as a houseplant for sunny windows; it is often grafted onto oleander for this purpose.

description

Adenium obesum is a stem, succulent, almost evergreen plant that grows as a shrub and forms a strongly thickened trunk ( caudex ). It reaches heights of growth of around 4, rarely up to 6 meters. The strongly thickening trunk can reach trunk diameters of 1 to 2 meters. The bark of the trunk is pale gray-green, gray or brown and smooth; it has thick, transparent to white milky juice. The leaves , arranged in a spiral and heaped at the end of the shoot, are leathery and undivided. They are about 3 to 12 inches long and 0.2 to 6 inches wide. The leaves are linear to obovate and tapering at the base of the leaf. The petiole is up to 4 mm long. Stipules are tiny or completely absent.

Of terminal inflorescences sitting at 5 to 9 mm long stems flowers . The hermaphrodite flowers are fivefold. The sepals are 6 to 12 mm long and hairy. The five petals are fused and light pink to dark red in color. The corolla tube is 2 to 4.5 cm long and 0.9 to 1.7 cm wide. The corolla lobes are 1 to 3 cm long and 0.5 to 2.5 cm wide. The stamens sit near the base of the corolla tube. The anthers cover the pistil in a cone shape . The upper ovary consists of two free carpels .

The fruit consists of two follicles grown together at the base and is 11 to 22 cm long. The fruit tapers at both ends; it is gray to pale gray-brown and opens lengthways. The elongated seeds are 10 to 14 mm long and have flying hairs. The species of the genus Adenium have strikingly two wreaths of flying hair, one at the top and one at the bottom.

The plant has a milky sap that is poisonous due to its cardenolide content .

The chromosome number is 2n = 22.

ecology

Adenium obesum usually loses its leaves in the dry season and then blooms during the dry season. The fertilization takes place by insects with enough long trunk. The fruits ripen about 2 to 3 months after fertilization.

Distribution and location

blossom
Adenium obesum in Tanzania
Adenium obesum in Ethiopia

The "desert rose" ( Adenium obesum ) is native to the steppe areas of Africa and Arabia . It prefers to grow in semi-arid climates. Occurrences extend from Senegal to Ethiopia and from Somalia to Tanzania ; the species is also found in Egypt and on the Arabian Peninsula and on Socotra . It is unclear whether the West African locations are original or whether the species was introduced there by humans. The species has now also become naturalized in Sri Lanka and parts of Southeast Asia , especially Thailand . The plant is very sensitive to frost. Today it is cultivated worldwide as an ornamental plant.

Adenium obesum occurs naturally in the savannah, dry bushland or bushy grassland on stony to sandy soils at altitudes up to 2100 m.

use

In large parts of Africa, the milky sap obtained from roots or trunks is used as an arrow poison . The poison is popular for hunting big game, as it kills the animals relatively quickly and they can only travel a maximum of 2 km after a hit. The Hadza people in Tanzania use the juice of the Adenium obesum partly unmixed, partly combined with the poison of Strophanthus eminii Asch. & Pax . The Duruma people in Kenya use the juice partly combined with roots and wood from Acokanthera schimperi (A.DC.) Schweinf. or with the milky sap of Synadenium pereskiifolium (Baill.) Guillaumin . The use of the milky sap of Adenium obesum is also known from Senegal, Nigeria and Cameroon.

A decoction made from bark and leaves is used as a fish poison in Nigeria, Cameroon and East Africa, among others. Its use in executions and murders has been reported in Mauritania and Senegal.

Adenium obesum is also used as a medicinal plant in traditional medicine in Africa. In the Sahel zone , a decoction from the roots, sometimes combined with other plants, is used for sexually transmitted diseases . A root or bark extract, used as a bath or lotion, is used to heal skin diseases and kill lice. The latex is used for rotten teeth and inflamed wounds.

This species of plant is sometimes planted as a living hedge, in Tanzania it is planted to indicate the location of graves. Mostly, however, it is cultivated as an ornamental plant because of its unusual growth shape and its attractive flowers.

Some of the wood is used as firewood .

Systematics

The first description of the species under the taxon Nerium obesum by the botanist Peter Forsskål was published in 1775. Johann Jacob Römer and Josef August Schultes referred to this Basionym in 1819 , but moved the species out of the genus Nerium under the new taxon Adenium obesum . Further synonyms for the species are: Adenium coetaneum Stapf , Adenium honghel A.DC. , Adenium socotranum Vierh. (1904) and Adenium somalense Balf.f. (1888).

Cultivated forms

Many cultivated forms have emerged; here is a selection:

  • 'Fritz Dederer': With thick, corky bark.
  • 'Mombasa': Dwarf form with many branches
  • 'Red Everbloomer'
  • 'Singapore': flower dark pink.
  • 'Tom Grumbleys': With white flowers.

Hybrids such as 'Asha', 'Endless Sunset', 'Perpetual Pink' and 'Volcanic Sunset' were also created by crossing with Adenium swazicum .

Individual evidence

  1. ↑ K. Schumann: Apocynaceae. In: A. Engler, C. Prantl: The natural plant families ... IV. Part, 2nd section, page 177. Leipzig 1895.
  2. ↑ Rafaël Govaerts (ed.): Adenium obesum. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved September 24, 2019.
  3. ↑ Flora ægyptiaco-arabica, p. 205, 1775.
  4. ↑ Systema Vegetabilium, Volume 4: p. 411, 1819.

literature

  • Rob Herwig: House Plants. The complete guide to living with greenery . Lexicographical Institute, Munich 1987 (edited by Edgar Gugenhan, book no. 04652-4, translation of the Dutch "Het volkomen kamerplantenboek").

swell

Web links

Commons : Adenium obesum  - collection of images, videos and audio files