Koso tree

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Koso tree
Koso tree (Hagenia abyssinica), illustration

Koso tree ( Hagenia abyssinica ), illustration

Systematics
Order : Rose-like (rosales)
Family : Rose family (Rosaceae)
Subfamily : Rosoideae
Tribe : Sanguisorbeae
Genre : Hagenia
Type : Koso tree
Scientific name of the  genus
Hagenia
JFGmel.
Scientific name of the  species
Hagenia abyssinica
( Bruce ) JFGmel.

The hagenia or Kossobaum ( Hagenia abyssinica ) is the only kind of monotypic genus Hagenia within the family of the rose family (Rosaceae). The home is in the mountains of Eastern , Central and Southern Africa ( Eritrea , Ethiopia , Sudan , Kenya , Tanzania , Uganda , Burundi , Central African Republic , Rwanda , eastern Zaire , Malawi , Zambia ), mostly at altitudes above 2000 meters .

description

Appearance and bark

Hagenia abyssinica grows as a slender, small to medium-sized tree and reaches heights of up to 20 meters and trunk diameters of usually 60 to rarely 220 centimeters. It forms a short, rarely straight trunk and thick branches. The treetop is wide and umbrella-shaped. The bark of the twigs, marked by ring-shaped long-lasting leaf scars, is initially thickly covered with short, shaggy and long, soft silvery hairs; often the glandular hair later turns reddish green or brown. The thick, brown or reddish-brown bark peels off quickly. There are no thorns and no buttress roots.

leaf

The alternate leaves , heaped in clusters at the branch ends, are around 40 to 50 cm long. The approximately 12 to 15 cm long petiole is fused with the two up to 1.5 cm wide, thin stipules and thus winged. These leaf wings, which are densely hairy underneath, surround the branches with their base like a sheath. The imparipinnate leaf blade has on the leaf rhachis alternate to almost opposite arranged three to six (up to eight) pairs of almost sessile pinnate leaves and the terminal leaflet. With a length of 9 to 15 cm and a width of 2 to 5 cm, the leaflets are narrow-elongated to elliptical with a slate, blunt base and a pointed upper end. The edge of the leaflets is serrated and has long, silky hair, with the leaf teeth usually ending in a thickened gland. The top of the leaflets is light or bright green and there are silvery hairs on the underside of the leaf. The pinnate leaves are pinnately veined and on the underside the leaf veins are raised and have long, silvery hair. Much smaller leaflets can alternate with the normal leaflets, which are almost circular with a diameter of up to 2.5 cm.

Inflorescence and flower

Hagenia abyssinica is polygamo-diocese . The terminal, multi-branched, overhanging, panicle inflorescences have a length of up to 60 centimeters and a diameter of about 30 centimeters and contain many flowers. The yellowish often tinted bright red inflorescence rachis is usually a zigzag manner and on foliage leaf-like bracts standing branches are shaggy and long silky hairy and sticky. The up to 3.5 millimeters long, densely hairy flower stalks are surrounded at their base by kidney-shaped bracts . The female inflorescences are pink and the male orange-buff to white.

The unisexual flowers are radial symmetry and rarely four, mostly five-fold. The silky hairy flower cup (hypanthium) is conical with a length of 2 to 3 millimeters. The secondary calyx and calyx are tinted green or reddish and rarely four-, mostly five-lobed. In the male flowers, the tips of the secondary calyx are smaller than those of the calyx. In the female flowers, the tips of the secondary calyx are larger than those of the calyx and enlarge to a length of up to 10 millimeters until the fruit is ripe. The rarely four, usually five petals are up to 1.5 millimeters long. In male flowers there are 15 to 20 fertile stamens with stamens up to 3 millimeters long. There are rudimentary stamens in female flowers and a functionally sterile gynoeceum in male flowers . Free from the flower cup, there are usually two pistils in the female flowers, the ovary has a tuft of hair at the top and the almost thread-shaped stylus ends in a cephalic scar. Usually only one of the two ovaries develops into a fruit.

Fruit and seeds

The fruit is surrounded by the durable flower cup and the secondary calyx forms wings. The relatively small, dry, single-seeded achene , with a diameter of up to 2.5 mm, is spherical to egg-shaped , winged and asymmetrical. The paper-like and thin pericarp is pale to brown. There are white hairs on the fruit. The almost spherical to almost egg-shaped seed is only slightly smaller than the fruit. The seed coat (testa) is usually wrinkled, brown and bare.

Systematics

In 1790 James Bruce published the name Banksia invalid in Travels , 5, p. 73 , which was already validly used in 1775 by Johann Reinhold Forster and Johann Georg Adam Forster in Characteres Generum Plantarum , 4 for the genus Banksia . In 1791 Johann Friedrich Gmelin replaced the invalid name with Hagenia in Systema Naturae ... editio decima tertia, aucta, reformata , Volume 2, Pages 600 and 613 .

Synonyms for Hagenia abyssinica (Bruce) JFGmel. are: Banksia abyssinica Bruce , Brayera anthelmintica Brayer , Hagenia abyssinica var. viridifolia Hauman , Hagenia anthelmintica (Kunth) Eggleling . Synonyms for Hagenia J.F.Gmel. are Banksia Bruce (an invalid homonym of Banksia J.R. Forst . & G. Forst . ) and Brayera Kunth . The generic name Hagenia honors the Königsberg polymath Karl Gottfried Hagen (1749–1829). The specific epithet abyssinica means from Ethiopia.

Hagenia abyssinica is the only species of the monotypic genus Hagenia and is closely related to the monotypical genus Leucosidea . The genus Hagenia belongs to the subtribe Agrimoniinae from the tribe Sanguisorbeae in the subfamily Rosoideae within the family Rosaceae .

use

Due to the many reddish flowers, Hagenia abyssinica is used as an ornamental plant.

In the highlands of Tanzania, Hagenia abyssinica is planted in forestry in the montane forests. In Tanzania, Hagenia abyssinica is used in a variety of ways, for example as firewood, the leaves as animal feed and green manure and the seeds as a food additive or spice . In the Kilimanjaro region , the bark is used to dye textiles yellowish-red (dye plant ).

Use of the wood

The beautiful looking wood is used to make furniture, floors, tools, fences and as lumber. From it are veneers made.

The sapwood is creamy yellow. The heartwood is dark red to red-brown, soft and medium-heavy (560 to 750 kg / m³ with a wood moisture content of 12%). The fibers are mostly straight. The Kosso wood is not durable and is attacked by drill beetles and termites . Deformation may occur during drying. The wood is easy to saw and nails hold up well.

Pharmaceutical use

The fresh flowers are used as tapeworm remedies because of the tannins they contain . As a drug : Koso flowers = Flores Koso, the female inflorescences are used. The effect of Hagenia abyssinica as an anthelmintic has been used in medicine in Ethiopia and other parts of Africa for a very long time. In Ethiopian folk medicine , extracts from dried flowers were given to drink once every one to three months against tapeworms, which were and still are common parasites in Ethiopia due to the consumption of raw meat. The kosso extract is drunk before breakfast and the laxative effect begins about 0.5 to 3 hours later. The head of the tapeworm (Scolex) is seldom excreted and so the tapeworm can grow again, so it is necessary to repeat it every one to three months. Along with other plant species, Hagenia abyssinica became the most important treatment for tapeworms in Ethiopia.

In the 19th century, the drug kosso was widely used as an anthelmintic in Europe. It was also often used in concoctions with other plant parts as a medicine to treat syphilis , scrofula , malaria , fever and cough . The drug Kosso powder can easily be stretched through any other brownish powder, on the other hand intact parts of the inflorescence can easily be recognized and are therefore relatively forgery-proof.

swell

Individual evidence

  1. ^ A b c Hagenia in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  2. ↑ a b c d e f g h i j k l P. CM Jansen & Getachew Aweke, 2002: data sheet - Hagenia abyssinica (Bruce) JFGmel. at Protabase - PROTA ( Plant Resources of Tropical Africa / Ressources végétales de l'Afrique tropicale ). ( Memento from December 16, 2011 in the Internet Archive )
  3. ↑ JF Gmelin 1791 scanned in at biodiversitylibrary.org .
  4. ^ Hagenia abyssinica at Tropicos.org. Missouri Botanical Garden, St. Louis
  5. ↑ Data sheet - Hagenia abyssinica at The Wood Explorer .
  6. ↑ Mannfried Pahlow: The great book of medicinal plants. Weltbild, Augsburg 2005, ISBN 3-8289-1839-5 .
  7. ↑ Gerhard Madaus: Textbook of Biological Remedies , 1938.

Web links

Supplementary literature