Baobabs

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Baobabs
African baobab tree (Adansonia digitata)

African baobab tree ( Adansonia digitata )

Systematics
Rosids
Eurosiden II
Order : Mallow-like (Malvales)
Family : Mallow family (Malvaceae)
Subfamily : Woolly trees (Bombacoideae)
Genre : Baobabs
Scientific name
Adansonia
L.

The baobab trees ( Adansonia ) are a genus of large, distinctive and often bizarre growing deciduous trees from the subfamily of the woolen tree (Bombacoideae), which in turn comes from the family of the mallow family (Malvaceae). The genus is divided into three sections based on flower, fruit and seed characteristics . The baobabs are common in large parts of the African continent, on the island of Madagascar and in Australia . The botanical name of the genus Adansonia was given by Bernard de Jussieu in honor of the French botanist Michel Adanson .

Its best-known representative is the African baobab tree ( Adansonia digitata ), which is also depicted in the coat of arms of Senegal , whose commercial use has been gaining in importance for several years.

description

Vegetative characteristics

Adansonia digitata flower bud
Flower of Adansonia digitata (Section Adansonia )
Flower of Adansonia rubrostipa (Section Longitubae )

The Adansonia species are deciduous trees that shed deciduous trees in the dry season and reach heights of about 5 to 30 meters. The huge, unreinforced trunks are cylindrical, conical or bottle-shaped. They usually have compact treetops . The unreinforced (rarely set with conical thorns , e.g. in Adansonia rubrostipa ) main branches are horizontal or ascending. The reddish brown to greenish bark is smooth or leafy and often has a yellow or green photosynthetic layer near the surface. The inner layers consist of tough longitudinal fibers. The wood is fibrous and soft. It secretes an odorless, sticky resin from injuries . Juvenile plants are slender, with tapered stems that are often puffy at the base. The internodes at the tip of the growth zone are very short, but longer on the young shoots .

The palm-shaped, pinnate leaves are arranged spirally on the branches and are membranous to leathery. The petiole is provided with two joints ( bipulvinat ). The five to eleven sessile or stalked leaflets are elliptical, lanceolate or reverse lanceolate, with the lateral partial leaves being smaller than the central ones. The partial leaves are bald to tomentose with simple or grouped hairs . The leaflets are usually pointed to a point (apiculate), rarely blunt. The leaf margin is entire or toothed. The leaves are shed during the dry season. The stipules , up to 2 millimeters long , soon fall off; they are rarely 1 to 1.5 centimeters long and permanent.

Inflorescences and flowers

The upright and only Adansonia digitata hanging blooms sit individually or in pairs rarely in axillary inflorescences . These are in groups of up to five at the branch ends. Pedicel and peduncle are more or less separated, the latter has three early sloping (caducose) bracts . The buds are almost spherical, egg-shaped or cylindrical.

The hermaphrodite, five-fold flowers are built with radial symmetry to slightly zygomorphic . The flower cup is scaled on the outside, green or brown and on the inside silk-like, cream-colored, pink-red or red. At the bottom there is a narrow strip of tissue that secretes nectar . It can also form an annular recess which is formed through the bottom of the goblet tube. The five sepals are more or less fused together and their tips are bent back or curved at the base of the flower. The five free, curved petals are creamy white, yellow or red.

There are numerous (100 to 1100) stamens , usually glabrous and white or yellowish. The lower half of the stamens is fused into a tube that is cylindrical or slightly tapered. The upper half of the stamens is free. The anthers are free and curved. They are monothecic and open with a longitudinal crack.

Five carpels are a top permanent ( hypogynen ) ovary fused; it is conical to elongated, brown or yellowish and tomentose with hairs pointing upwards. The numerous anatropic ovules are carried by long, dichotomous umbilical cords (funiculi), which arise from seven to nine deeply embedded placentas . The style is simple, thin, white or densely matted and dark red at the base. The scar usually consists of five to ten yellowish or dark red, short lobes.

Fruits and seeds

Fruits of an Adansonia digitata from Burkina Faso
Seeds of Adansonia digitata

The spherical, ovoid, or ovoid-cylindrical fruit is a dry, large, many-seeded berry that does not usually burst. Their 5 to 15 millimeters thick, felty, hard and woolly pericarp is reddish or blackish brown. The kidney-shaped, 10 to 15 (rarely 20) millimeters long seeds are embedded in a white or cream-colored, dry, powder-like or sponge-like pulp .

The two (rarely several) cotyledons are about the same size, folded and chlorophyllless . They remain inside the seed coat (cryptocotylar) or unfold outside (phanerocotylar). Young leaves are initially simple, later lobed, trifoliate or irregularly finger-shaped.

genetics

The chromosome number for Adansonia digitata is 2n = 160, for all other species 2n = 88.

ecology

The pollination of Adansonia digitata by the nectar-eating palm bat ( Eidolon helvum ) was observed for the first time in 1935 by the Viennese biologist Otto Porsch (1875–1959) in the botanical garden of Bogor on the island of Java . Later the Egyptian bat ( Rousettus aegyptiacus ) and the flying fox Epomophorus wahlbergii were identified as pollinators. It was widely believed that flying foxes also pollinated the rest of the species in the genus. The observations made by David Alastair Baum in the mid-1990s gave a much more nuanced picture. After that, hawks and lemurs also contribute to pollination.

Galagos ( Galago crassicaudatus ), blowflies ( Chrysomyia marginalis ), owl butterflies ( Heliothis armigera and Diparopsis castanea ), chewy owls ( Earias biplaga ) and insects from the order of the hymenoptera visit the flowers for their nectar.

Distribution and locations

Adansonia digitata is common in the semi-arid areas of Africa south of the Sahara . There is a gap in the area of ​​the Central African Republic between the occurrences in East Africa and West Africa . The southernmost distribution area is the Transvaal in South Africa . The northernmost occurrences are in the south of Sudan and Ethiopia . In Madagascar , Adansonia digitata was very likely introduced by humans, as the trees are almost exclusively near villages.

Adansonia gibbosa is common in northwestern Australia.

Six of the eight known species are distributed exclusively in Madagascar from the north along the west coast to the south of the island.

Systematics

Adansonia grandidieri in Madagascar
Adansonia gregorii in Western Australia

External system

In 1789, Antoine-Laurent de Jussieu assigned Adansonia to the Malvaceae family that he had established. In 1822 Karl Kunth separated ten genera, including Adansonia , into the wool tree family (Bombacaceae). Today Adansonia is led as a subfamily Bombacoideae of the mallow family and is classified there in the tribe Adansonieae .

Adansonia is very likely monophyletic .

Internal system

The type species of the genus is Adansonia digitata . Synonyms are Baobab Adans. , Ophelus Lour. and Baobabus Kuntze .

In 1908, Bénédict Pierre Georges Hochreutiner divided the genus Adansonia into three sections based on flower, fruit and seed characteristics:

Botanical history

Fruit and leaves of Adansonia digitata on a figure in Exoticorum Libri Decem by Charles de l'Écluse (1605)

The first description in which one can recognize an Adansonia digitata comes from the traveler Ibn Battuta . In 1352 he reported about a weaver in Mali who did his work under the protection of a hollow tree trunk. Even Leo Africanus , the 1511-1517 North Africa traveled, knew the tree.

The earliest mention in Europe comes from Julius Caesar Scaliger , who described it in 1557 under the name Guanabus . By Prospero Alpini , the fruit sold in European markets as Hobab bu were known, came the first, 1592 published illustration of a baobab fruit and an imaginative drawing of leaves and flowers. Charles de l'Écluse gave the first correct representation of the leaves in 1605.

Bernard de Jussieu told Carl von Linné of a species discovered by Michel Adanson , which Jussieu called Charadrium spinosum Adansonia . Linnaeus then added this to the appendix of Species Plantarum as Adansonia without description . Linnaeus only received a description of the genus, called Bahobab by Adanson , in a letter from Michel Adanson dated October 2, 1758, which he finally listed in 1764 in the 6th edition of Genera Plantarum . Adanson himself did not recognize the name Adansonia and instead used baobab in the Familles des Plantes of 1763 .

With the exception of Adansonia perrieri , whose first description dates back to 1960, all other species were discovered and described in the period from about the middle to the end of the 19th century.

Gerald Ernest Wickens (* 1927) compiled the first extensive monograph on the African baobab tree in 1982, which revealed astonishing gaps in the existing scientific knowledge. David Alastair Baum (* 1964) carried out extensive field studies at the locations of the individual species and examined the existing herbarium material. On this basis he published a systematic revision of the entire genus Adansonia in 1995 .

use

Traditional use

All parts of Adansonia species are used, with the use of Adansonia digitata being most extensively documented.

The roots are cooked and eaten in West Africa during times of famine. The Temne use it to brew a root brew against obesity . In East Africa, a red, soluble dye is made from them. The fibrous root bark is used to make cords or ropes, for fishing nets, doormats and socks.

Hollowed out tree trunks serve as a water reservoir, grave, prison, stable, toilet, refrigerator, milk shop and even as a dwelling.

From the fibers of the bark are u. a. Manufactured ropes, ropes, webbing, strings for musical instruments, baskets, nets and fishing lines. The dried bark is used as a remedy for fever. The bark is also used for roofing. Soap is made from the ashes of bark and fruits, boiled in oil.

The wood rots quickly in water, leaving behind long fibers that are used for packaging. In addition, it is used for light canoes, wooden panels, trays and floats for fishing nets.

Young leaves are prepared like spinach. Soups and sauces are seasoned with dried and powdered leaves. The pollen from the flowers mixed with water is used as glue.

commercial use

Fruit of Adansonia digitata

The commercial use of Adansonia digitata in Africa is mainly limited to the production of fruit juices and confectionery for domestic consumption, as well as wickerwork for tourism . The Tanzania- based Foodtech Tanzania Enterprise markets a "baobab sauce" made from the fruit. The company PhytoTrade Africa , with offices in Harare ( Zimbabwe ) and London , represents manufacturers of natural products from southern Africa, including those whose products on Adansonia digitata based. The products sold include an oil made from the seeds for cosmetic products as well as a powder and a powder extract made from the fruit pulp, which can be used in the food industry, among other things. The Baobab Fruit Company Senegal now markets its products worldwide from Senegal .

For the distribution of baobab products within the European Union , the Baobab Fruit Company was founded in Italy in 2001 and the possibilities of marketing were examined.

From around 1874 until the early 20th century, the seeds of the Adansonia grandidieri species native to Madagascar were shipped from Morondava to Marseille , where they were used to produce an edible oil with other oil seeds .

Adansonia gregorii has been grown in Australia since 2001 to utilize the edible roots and leaves of the young plants.

Danger

On the International Union for Conservation of Nature and Natural Resources led the Red List of Threatened Species Six species. Adansonia perrieri , Adansonia grandidieri and Adansonia suarezensis are classified as " Endangered (EN) ". " Near Threatened (NT) " are Adansonia madagascariensis , Adansonia rubrostipa and Adansonia za .

proof

literature

  • David A. Baum: The Comparative Pollination and Floral Biology of Baobabs (Adansonia- Bombacaceae) . In: Annals of the Missouri Botanical Garden . Volume 82, No. 2, 1995, pp. 322-348
  • David A. Baum: A Systematic Revision of Adansonia (Bombacaceae) . In: Annals of the Missouri Botanical Garden . Volume 82, No. 3, 1995, pp. 440-471
  • Gerald E. Wickens: The Baobab - Africa's Upside-Down Tree . In: Kew Bulletin . Volume 37, No. 2, 1982

Individual evidence

Most of the information in this article has been taken from the sources given under literature; the following sources are also cited:

  1. ↑ Entry at FloraBase - the Western Australian Flora
  2. ↑ David A. Baum, Kazuo Oginuma: A Review of Chromosome Numbers in Bombacaceae with New Counts for Adansonia . In: Taxon . Vol. 43, No. 1, February 1994, pp. 11-20 JSTOR
  3. ^ Antoine-Laurent de Jussieu: Genera plantarum . Paris 1789, p. 275 online
  4. ^ Karl Sigismund Kunth: Nova genera et species plantarum . In: Alexander von Humboldt, Aimé Bonpland, Karl Sigismund Kunth: Voyage aux régions équinoxiales du Nouveau Continent . 1822
  5. ↑ David A. Baum, Randall L. Small, Jonathan F. Wendel: Biogeography and Floral Evolution of Baobabs (Adansonia, Bombacaceae) as Inferred from Multiple Data Sets . In: Systematic Biology . Volume 47, No. 2, June 1998, pp. 181–207 (PDF online; 1.0 MB)
  6. ↑ Fam. Pl. Ii. 399: 524 (1763);
  7. ↑ Flora cochinchinensis: sistens plantas in regno Cochinchina nascentes. Quibus accedunt aliæ observatæ in Sinensi imperio, Africa Orientali, Indiæque locis variis. Omnes dispositæ secundum systema sexuale Linnæanum. Ulyssipone p. 412 1790.
  8. ↑ Revisio Generum Plantarum: vascularium omnium atque cellularium multarum secundum leges nomeclaturae internationales cum enumeratione plantarum exoticarum in itinere mundi collectarum… Leipzig 1891, p. 66 online
  9. ^ Annuaire du Conservatoire et du Jardin Botaniques de Genève . 11-12, 1908
  10. ↑ Julius Caesar Scaliger: Exotericae exercitationes de subtilitate adversus Cardanum . Paris 1557
  11. ↑ Johann Bauhin u. a .: Historia Plantarum Universalis . Yverdon 1650, Volume 1: p. 110, online
  12. ↑ De plantis Aegypti liber . Venice 1592, p. 66, plates 67 and 68
  13. ↑ Carl von Linné: Species Plantarum . 1753, Volume 2, p. 1190
  14. ↑ Michel Adanson to Carl Linnaeus, October 2, 1758, letter L2446 in The Linnaean correspondence (accessed May 20, 2008).
  15. ↑ Carl von Linné: Genera Plantarum . 6th edition 1764, p. 352
  16. ↑ Gerald E. Wickens: The Baobab - Africa's Upside-Down Tree. In: Kew Bulletin. Volume 37, No. 2, p. 173, 1982
  17. ↑ Gerald E. Wickens, Pat Lowe: The Baobabs: Pachycauls of Africa, Madagascar and Australia . Springer 2007, p. 370
  18. ↑ Timothy Kitundu: Food industry goes big on health from the baobab tree. Archived from the original on January 15, 2012 ; Retrieved July 17, 2008 .
  19. ↑ By PhytoTrade Africa marketed products (accessed on 17 July 2008)
  20. ↑ Baobab Oil (accessed July 17, 2008)
  21. ↑ Baobab extract (accessed July 17, 2008)
  22. ↑ Baobab Fruit Pulp (accessed July 17, 2008)
  23. ↑ Baobab Fruit Company Senegal (accessed July 17, 2008)
  24. ↑ Baobab is branching out ... (accessed July 17, 2008)
  25. ↑ Baobab Dried Fruit Pulp - An application for Novel Foods Approval in the EU as a food ingredient . PDF online
  26. ↑ Yearbook of the West Australian Nut & Tree Crop Association: Quandong . Volume 33, No. 2, p. 12, 2007. PDF Online ( Memento from July 22, 2008 in the Internet Archive )
  27. ^ World Conservation Monitoring Center 1998. Adansonia perrieri . In: 2007 IUCN Red List of Threatened Species . IUCN 2007, accessed May 19, 2008.
  28. ^ World Conservation Monitoring Center 1998. Adansonia grandidieri . In: 2007 IUCN Red List of Threatened Species . IUCN 2007, accessed May 18, 2008.
  29. ^ World Conservation Monitoring Center 1998. Adansonia suarezensis . In: 2007 IUCN Red List of Threatened Species . IUCN 2007, accessed May 19, 2008.
  30. ^ World Conservation Monitoring Center 1998. Adansonia madagascariensis . In: 2007 IUCN Red List of Threatened Species . IUCN 2007, accessed May 18, 2008.
  31. ^ World Conservation Monitoring Center 1998. Adansonia rubrostipa . In: 2007 IUCN Red List of Threatened Species . IUCN 2007, accessed May 15, 2008.
  32. ^ World Conservation Monitoring Center 1998. Adansonia za . In: 2007 IUCN Red List of Threatened Species . IUCN 2007, accessed May 19, 2008.

further reading

  • Gerald E. Wickens, Pat Lowe: The Baobabs: Pachycauls of Africa, Madagascar and Australia . Springer 2007. ISBN 978-1-4020-6430-2

Web links

Commons : Baobabs ( Adansonia )  - Collection of images, videos and audio files
Wiktionary: baobab tree  - explanations of meanings, word origins, synonyms, translations
This version was added to the list of articles worth reading on August 13, 2008 .