Adansonia

Adansonia is a genus of medium-to-large deciduous trees known as baobabs (also boabab; or ). The eight species of Adansonia are native to Africa, Australia, and Madagascar but have also been introduced to other regions of the world, including Barbados, where several of the baobabs there are suspected to have originated from Africa. Other baobabs have been introduced to Asia. A genomic and ecological analysis further suggests that the genus itself originated from Madagascar.

The generic name Adansonia honours Michel Adanson, the French naturalist and explorer who provided the first detailed botanical description and illustrations of Adansonia digitata. The baobab, however, is also known as the "upside down tree," a name attributable to the trees' overall appearance and historical myths. Baobabs are among the longest-lived of vascular plants and have large flowers that are reproductive for a maximum of 15 hours. The flowers open around dusk with sufficiently rapid movement that is detectable by the naked eye.

Description

thumb|Adansonia digitata (African baobab) tree in Mikumi National Park with its fruits hanging

Baobabs are long-lived deciduous, small to large trees from tall Tree diameter fluctuates with rainfall so it is thought that water may be stored in the trunk.

Flowers may remain attached to the trees for several days, but the reproductive phase is very short, with pollen shed during the first night and stigmas shriveled by the morning. The flower is made up of an outer 5-lobed calyx, and an inner ring of petals set around a fused tube of stamens. There are eight accepted species of Adansonia. A new species (Adansonia kilima Pettigrew, et al.), was described in 2012, found in high-elevation sites in eastern and southern Africa. This, however, is no longer recognized as a distinct species but considered a synonym of A. digitata. Some high-elevation trees in Tanzania show different genetics and morphology, but further study is needed to determine if recognition of them as a separate species is warranted.

The lineage leading to Adansonia was found to have diverged from its closest relatives in Bombacoideae like Ceiba /Chorisia at the end of the Eocene, during a time of abrupt global climate cooling and drying, while a divergence of this Adansonia+Ceiba /Chorisia clade from Pachira was found to be more ancient, dating to the middle Eocene.

{| class="wikitable"

|+ List of species of Adansonia

!Image !!Species !! Common names !! Native range

|120px|| Adansonia digitata L. (also includes Adansonia kilima

|120px ||Adansonia grandidieri Baill.|| Grandidier's baobab, giant baobab|| west central Madagascar

|120px ||Adansonia gregorii F.Muell. (syn. A. gibbosa) || boab, Australian baobab, bottletree, cream-of-tartar-tree, gouty-stem|| Australia (Northern Territory, Western Australia)

|120px ||Adansonia madagascariensis Baill.|| Madagascar baobab|| northwest and north Madagascar

| frameless|160x160px||Adansonia perrieri Capuron|| Perrier's baobab|| northern Madagascar The tree also grows wild in Sudan in the regions of Darfur and the state of Kordofan. The locals call it "Gongolaze" and use its fruits as food and medicine and use the tree trunks as reservoirs to save water.

Ecology

Baobabs store water in the trunk (up to ) to endure harsh drought conditions. All occur in seasonally arid areas, and are deciduous, shedding their leaves during the dry season. Across Africa, the oldest and largest baobabs began to die in the early 21st century, likely from a combination of drought and rising temperatures. and four species of weaver.

Notable trees

thumb|"Grandmother" Fony baobab

Radiocarbon dating has provided data on a few individuals of A. digitata. The Panke baobab in Zimbabwe was some 2,450 years old when it died in 2011, making it the oldest angiosperm ever documented, and two other trees—Dorslandboom in Namibia and Glencoe in South Africa—were estimated to be approximately 2,000 years old. The Glencoe Baobab, a specimen of A. digitata in Limpopo Province, South Africa, was considered to be the largest living individual, with a maximum circumference of and a diameter of about . The tree has since split into two parts, so the widest individual trunk may now be that of the Sunland Baobab, or Platland tree, also in South Africa. The diameter of this tree at ground level is and its circumference at breast height is . One called Grandmother is made up of three fused trunks of different ages, with the oldest part of the tree an estimated 1,600 years old. The second, "polygamous baobab", has six fused stems, and is an estimated 1,000 years old. It is a good source of vitamin C, potassium, carbohydrates, and phosphorus. The dried fruit powder of A. digitata, baobab powder, contains about 11% water, 80% carbohydrates (50% fiber), and modest levels of various nutrients, including riboflavin, calcium, magnesium, potassium, iron, and phytosterols, with low levels of protein and fats. Vitamin C content, described as variable in different samples, was in a range of per of dried powder. and later in the year was granted GRAS (generally recognized as safe) status in the United States.

In Angola, the dry fruit of A. digitata is usually boiled, and the broth is used for juices or as the base for a type of ice cream known as gelado de múcua. In Zimbabwe, the fruit of A. digitata is eaten fresh or the crushed crumbly pulp is stirred into porridge and drinks. In Tanzania, the dry pulp of A. digitata is added to sugarcane to aid fermentation in brewing (beermaking).

Seed

The seeds of some species are a source of vegetable oil. and A. za are eaten fresh.

Other uses

Some baobab species are sources of fiber, dye, and fuel. Indigenous Australians used the native species A. gregorii for several products, making string from the root fibers and decorative crafts from the fruits. Baobab oil from the seed is also used in cosmetics, particularly in moisturizers.

In culture

Baobab trees hold cultural and spiritual significance in many African societies. They are often the sites of communal gatherings, storytelling, and rituals. An unusual baobab was the namesake of Kukawa, formerly the capital of the Bornu Empire southwest of Lake Chad in Central Africa.

In the novel The Little Prince, the titular character takes care to root out baobabs that try to grow on his tiny planet home. The fearsome, grasping baobab trees, researchers have contended, were meant to represent Nazism attempting to destroy the planet.

Gallery

File:Adansonia digitata Baobab.JPG|Adansonia digitata

File:Derby boab, Western Australia.jpg|Adansonia gregorii

File:Rubostipaanjajavycmichaelhogan.jpg|Adansonia rubrostipa

File:Adansonia suarezensis.jpg|Adansonia suarezensis

File:Starr 080305-3303 Adansonia digitata.jpg|Adansonia digitata leaf

File:Adansonia digitata (1).jpg|Adansonia digitata flower

File:Pollen of Adansonia or Baobab tree.jpg|Adansonia pollen

File:Baobab - seeds from one fruit, Adansonia digitata.jpg|Adansonia digitata seeds from the fruit

File:Raw baobab powder on white paper.jpg|Baobab powder

File:Baobab - fruit pulp elements detail - Adansonia digitata.jpg|Elements of the fruit pulp of Adansonia digitata (clockwise from top right): whole fruit pulp chunks, fibers, seeds, powder from the pulp

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References

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