Acokanthera

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Acokanthera
Acokanthera rotundata in the habitat near Louwsburg in KwaZulu-Natal, South Africa

Acokanthera rotundata in the habitat near Louwsburg in KwaZulu-Natal , South Africa

Systematics
Euasterids I
Order : Enzianartige (Gentianales)
Family : Dog poison family (Apocynaceae)
Subfamily : Rauvolfioideae
Tribe : Carisseae
Genre : Acokanthera
Scientific name
Acokanthera
G.Don

The Acokanthera are a genus of plants within the dog venom family (Apocynaceae). The approximately five species are distributed in tropical to southern Africa and in Arabia. Some species are called beautiful poison .

description

Illustration of the arrowhead beautiful poison ( Acokanthera schimperi ) from Koehler's medicinal plants , 1897: “ Acokanthera schimperi. A flowering branch. B fruit branch. 1 cup; 2 corollas, cut open; 3 stamen; 4 pestle; 5 ovary; 6 fruit, partly cut open; 7 seeds; 8 cross section; 9 longitudinal section in the direction a to c; 10 Longitudinal section in the direction b to d. A, B reduced, enlarged 1 to 10. "
Lateral inflorescences of the African beautiful poison ( Acokanthera oblongifolia )
Fruits of the African beautiful poison ( Acokanthera oblongifolia )

Appearance and leaves

Acokanthera species grow as evergreen trees or shrubs . They contain white milky juice .

The (almost) oppositely arranged leaves have a more or less short petiole. The leaf blade is simple.

Inflorescences and flowers

The umbrella-like inflorescences are lateral, at most on short inflorescence shafts or are sessile, often in bundles. A flower stalk is hardly recognizable.

The mostly sweet-smelling, hermaphrodite flowers are radial symmetry and five-fold with a double flower envelope . The five small sepals are only briefly fused and have no glands on the inside. The five white or pink-colored petals are fused together in the shape of a salver and the corolla tube widens slightly near the corolla throat. The five short crown lobes overlap to the left. There is no secondary crown. There is only one circle with five stamens . The short stamens are inserted in the widened area of ​​the corolla tube. The anthers are ovate to oblong and pointed; the connective arises in a short, tiny hairy point and is briefly two-lobed at the base. There is no discus. The two carpels are an above-permanent, two-chambered ovary grown. Each ovary chamber contains only one ovule . The thread-like stylus is cylindrical or briefly conical in the upper area with a ring of papillae and ends in a short two-lobed scar .

Fruits and seeds

The spherical to elliptical berries have a woody endocarp and contain one or two seeds .

The seeds do not have a tuft of hair and contain the embryo with two egg-shaped wide or nearly heart-shaped cotyledons ( cotyledons ) and a top permanent radicle .

Bushman's beautiful venom leaves ( Acokanthera oppositifolia )
Inflorescences of Bushman's beautiful poison ( Acokanthera oppositifolia )
Variegated variety 'Variegata' of the African beautiful poison ( Acokanthera oblongifolia )

Systematics and distribution

The genus Acokanthera was established in 1837 by George Don in A General History of the Dichlamydeous Plants , 4, p. 485. A synonym for Acokanthera G. Don is Toxicophlaea Harv. The generic name Acokanthera is derived from the Greek words acoce for prickly pointed and anthera for anthers, so it stands for a prickly pointed anthers.

The Acokanthera species are native to tropical and southern Africa and Arabia.

The genus Acokanthera belongs to the tribe Carisseae in the subfamily Rauvolfioideae within the family Apocynaceae .

There are about five types of Acokanthera :

ingredients

The wood of Acokanthera ouabaio contains ouabain , which is identical to the officinal g-strophanthin obtained from Strophanthus gratus .

use

Acokanthera oblongifolia and Acokanthera oppositifolia are used as an ornamental plant.

The milky sap of Acokanthera schimperi and Acokanthera oppositifolia is used as arrow poison in hunting. A poisonous black substance was found on 6,000-year-old arrowheads from Egypt , which is believed to be a substance from Acokanthera spec. acts.

swell

Individual evidence

  1. ↑ a b c d e f g h Bingtao Li, Antony JM Leeuwenberg, David J. Middleton: Apocynaceae. : Acokanthera. , P. 147 - online with the same text as the printed work , In: Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China. Volume 16: Gentianaceae through Boraginaceae. Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, 1995, ISBN 0-915279-33-9 .
  2. ↑ a b c d First publication scanned at biodiversitylibrary.org .
  3. ↑ a b c Acokanthera oppositifolia and Acokanthera oblongifolia at PlantZAfrica of the South African National Biodiversity Institute = SANBI.
  4. ^ Acokanthera at Tropicos.org. Missouri Botanical Garden, St. Louis, Retrieved November 11, 2017.
  5. ↑ a b c d e f Acokanthera in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved November 11, 2017.
  6. ↑ a b c d e f g Rafaël Govaerts (Ed.): Acokanthera. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 11, 2017.
  7. ↑ a b c Species list for Acokanthera in the Red List of South African Plants
  8. ↑ Ernst Friedrich Gilg, Herbert Thoms, Hans Schedel: The Strophanthus question. Berlin 1904, p. 31.
  9. ↑ Gordon Cheers (Ed.): Botanica. The ABC of plants. 10,000 species in text and images . Könemann Verlagsgesellschaft, 2003, ISBN 3-8331-1600-5 , p. 53-54 .
  10. ↑ 6000 year old poison arrows at www.spiegel.de .

Web links

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

Supplementary literature

  • S. Nazimuddin, Mohammad Qaiser: Flora of Pakistan 148: Apocynaceae . Department of Botany, University of Karachi, Karachi 1983, p. 3 ( online at: efloras.org [accessed December 27, 2012]). (With too many species, so not the same size.)