Adansonia is agenus made up of eightspecies of medium-to-largedeciduous trees known asbaobabs (/ˈbaʊbæb/ or/ˈbeɪoʊbæb/) oradansonias. They are placed in thefamilyMalvaceae, subfamilyBombacoideae. They are native toMadagascar, mainland Africa, and Australia.[2] The trees have also been introduced to other regions such as Asia,[3] and several specimens of suspected African origin are found in Barbados.[4][5] Agenomic andecological analysis has suggested that the genus is Madagascan in origin.[6]
Thegeneric name honoursMichel Adanson, the French naturalist and explorer who describedAdansonia digitata.[7] The baobab is also known as the "upside down tree", a name that originates from its appearance and several myths.[8] They are among the most long-lived ofvascular plants[9] and have large flowers that are reproductive for a maximum of 15 hours.[10] The flowers open around dusk, opening so quickly that movement can be detected by the naked eye, and are faded by the next morning.[10] The fruits are large, oval to round and berry-like and hold kidney-shaped seeds in a dry, pulpy matrix.
In the early 21st century, baobabs in southern Africa began to die off rapidly from a cause yet to be determined. It is unlikely that disease or pests would be able to kill many trees so rapidly, and some have speculated that the die-off is a result ofdehydration.[11][12]
Adansonia digitata (African baobab) tree in Mikumi National Park with its fruits hanging
Baobabs are long-lived deciduous, small to large trees from 5 to 30 m (20 to 100 ft) tall[10] with broad trunks and compact crowns. Young trees usually have slender, tapering trunks, often with a swollen base. Mature trees have massive trunks that are bottle-shaped or cylindrical and tapered from bottom to top.[10] The trunk is made of fibrous wood arranged in concentric rings, although rings are not always formed annually and so cannot be used to determine the age of individual trees.[13] Tree diameter fluctuates with rainfall so it is thought that water may be stored in the trunk.[10] Baobab trees have two types of shoots—long, green vegetative ones, and stout, woody reproductive ones. Branches can be massive and spread out horizontally from the trunk or are ascending.
Adansonia gregorii is generally the smallest of the baobabs, rarely getting to over 10 m (33 ft) tall and often with multiple trunks.[10] BothA. rubrostipa andA. madagascariensis are small to large trees, from 5 to 20 m (16 to 66 ft) tall.[10] The other baobabs grow from 25 to 30 m (80 to 100 ft) tall, with 2 to 3 m (7 to 10 ft) diameter trunks.A. digitata, however, often has massive single or multiple trunks of up to 10 m (33 ft) diameter.[10]
Leaves arepalmately compound in mature trees, but seedlings and regenerating shoots may have simple leaves. The transition to compound leaves comes with age and may be gradual. Leaves have 5–11 leaflets, with the largest ones in the middle and may be stalkless or with shortpetioles. Leaflets may have toothed or smooth edges, and may be hairless or have simple-to-clumped hairs. Baobabs havestipules at the base of the leaves, but the stipules are soon shed in most species. Baobabs are deciduous, shedding leaves during the dry season.[10]
Open flower showing distorted petals and the unfused ball of stamens set on top of the staminal tubeBisected flower showing the style running through the staminal tube, bending, then projecting out of the stamens
In mostAdansonia species, the flowers are borne on short erect or spreading stalks in the axils of the leaves near the tips of reproductive shoots. OnlyA. digitata has flowers and fruits set on long, hanging stalks. There is usually only a single flower in an axil, but sometimes flowers occur in pairs. They are large, showy and strongly scented. They only open near dusk. Opening is rapid and movement of the flower parts is fast enough to be visible. MostAdansonia species are pollinated by bats.[14]
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.[10] The outer lobes of the calyx are usually green (brown inA. grandidieri) and in bud are joined almost to the tip. As the flower opens, the calyx lobes split apart and become coiled or bent back (reflexed) at the base of the flower. The inner surface of the lobes are silky-hairy and cream, pink, or red.[10] Sometimes the lobes do not separate cleanly, distorting the shape of the flower as they bend back. The calyx lobes remain fused at the base, leaving a feature (calyx tube) that has nectar-producing tissue and that is cup-shaped, flat or tubular; the form of the calyx tube varies with species.[10] The flowers have a central tube (staminal tube) made up of fused stalks of stamens (filaments), with unfused filaments above. A densely hairy ovary is enclosed in the staminal tube, and a long style tipped with a stigma emerges from the filaments. Petals are set near the base of the staminal tube and are variable in shape and colour. The flowers, when fresh, may be white, cream, bright yellow or dark red, but fade quickly, often turning reddish when dried.[10]
The fruit of the baobabs is one of their distinguishing features. It is large, oval-to-round, and berry-like in most species (usually less than 10 centimetres (3.9 in) long inA. madagascariensis.[10]). It has a dry, hard outer shell of variable thickness. In most species, the shell is indehiscent (does not break open easily).A. gibbosa is the only species with fruits that crack while still on the tree, which then tend to break open upon landing on the ground. Inside the outer shell, kidney-shaped seeds 10–15(−20) mm long are set in a dry pulp.[10]
The earliest written reports of baobab are from a 14th-century travelogue by the Arab travelerIbn Battuta.[10] The first botanical description was in theDe medicina Aegyptiorum byProspero Alpini (1592), looking at fruits that he observed in Egypt from an unknown source. They were calledBahobab, possibly from the Arabicأَبُو حِبَابabū ḥibāb meaning "many-seeded fruit".[10] The French explorer and botanistMichel Adanson (1727–1806) observed a baobab tree in 1749 on the island of Sor in Senegal, and wrote the first detailed botanical description of the full tree, accompanied with illustrations. Recognizing the connection to the fruit described by Alpini he called the genus Baobab.Linnaeus later renamed the genusAdansonia, to honour Adanson, but use of baobab as one of the common names has persisted.[10]
ThegenusAdansonia is in the subfamilyBombacoideae, within the familyMalvaceae in the orderMalvales. The subfamily Bombacoideae was previously treated as theBombacaceae family but it is no longer recognized at the rank of family by theAngiosperm Phylogeny Group I 1998, II 2003 or theKubitzki system 2003. There are eight acceptedspecies ofAdansonia. A new species (Adansonia kilima Pettigrew, et al.), was described in 2012, found in high-elevation sites in eastern and southern Africa.[15] This, however, is no longer recognized as a distinct species[16] but considered a synonym ofA. 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.[16] The genusAdansonia is further divided into three sections. Section Adansonia includes onlyA. digitata. This species has hanging flowers and fruit, set on long flowering stalks. This is thetype species for the genusAdansonia.[10] All species ofAdansonia exceptA. digitata arediploid;A. digitata istetraploid.[15] Section Brevitubae includesA. grandidieri andA. suarexensis. These are species with flower buds that set on short pedicles and that are approximately twice as long as wide. The other species are all classified within the section Longitubae. They also have flowers/fruits set on short pedicels, but the flower buds are five or more times as long as wide.[citation needed]
As of July 2020[update], there are eight recognized species of Adansonia, with sixendemic toMadagascar, one native to mainland Africa and the Arabian Peninsula, and one native to Australia. The mainland African species (Adansonia digitata) also occurs on Madagascar, but it is not a native of that island. Baobabs were introduced in ancient times to south Asia and during the colonial era to the Caribbean. They are also present in the island nation ofCape Verde.[8] A ninth species was described in 2012 (Adansonia kilimaPettigrew, et al.)[15] but is no longer recognized as a distinct species.[16] The African and Australian baobabs are similar in appearance, and the oldest splits withinAdansonia are likely no older than 15 million years; thus, the Australian species represents a long-distance trans-oceanic dispersal event from Africa.[17] The lineage leading toAdansonia was found to have diverged from its closest relatives inBombacoideae likeCeiba /Chorisia at the end of the Eocene, during a time of abrupt global climate cooling and drying, while a divergence of thisAdansonia+Ceiba /Chorisia clade fromPachira was found to be more ancient, dating to the middle Eocene.[18]
The Malagasy species are important components of theMadagascar dry deciduous forests. Within thatbiome,Adansonia madagascariensis andA. rubrostipa occur specifically in theAnjajavy Forest, sometimes growing out of thetsingylimestone itself.A. digitata has been called "a defining icon of African bushland".[24] The tree also grows wild inSudan in the regions ofDarfur and the state ofKordofan. The locals call it "Gongolaze" and use its fruits as food and medicine and use the tree trunks as reservoirs to save water.[citation needed]
Baobabs store water in the trunk (up to 120,000 litres or 32,000 US gallons) to endure harsh drought conditions.[25] All occur in seasonallyarid areas, and aredeciduous, shedding theirleaves 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.[11] The trees appear to becomeparched, then becomedehydrated and unable to support their massive trunks.[12]
Radiocarbon dating has provided data on a few individuals ofA. digitata. The Panke baobab inZimbabwe was some 2,450 years old when it died in 2011, making it the oldestangiosperm ever documented,[28] and two other trees—Dorslandboom in Namibia andGlencoe in South Africa—were estimated to be approximately 2,000 years old.[29] Another specimen known asGrootboom was dated and found to be at least 1,275 years old.[24][30] TheGlencoe Baobab, a specimen ofA. digitata inLimpopo Province, South Africa, was considered to be the largest living individual, with a maximumcircumference of 47 m (154 ft)[31] and a diameter of about 15.9 m (52 ft). The tree has since split into two parts, so the widest individual trunk may now be that of theSunland Baobab, or Platland tree, also in South Africa. The diameter of this tree at ground level is 9.3 m (31 ft) and its circumference at breast height is 34 m (112 ft).[29]
Two large baobabs growing inTsimanampetsotse National Park were also studied using radiocarbon dating.[29] One calledGrandmother 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.[29]
The white pith in the fruit of the Australian baobab (A. gregorii) tastes likesherbet.[32] It has an acidic, tart, citrus flavor.[33] It is a good source ofvitamin C, potassium, carbohydrates, and phosphorus.[citation needed] The dried fruit powder ofA. digitata, baobab powder, contains about 11% water, 80%carbohydrates (50% fiber),[34] and modest levels of various nutrients, includingriboflavin,calcium,magnesium,potassium, iron, andphytosterols, with low levels ofprotein and fats.[33][35][36] Vitamin C content, described as variable in different samples, was in a range of 74 to 163 milligrams (1.14 to 2.52 gr) per 100 grams (3.5 oz) of dried powder.[33] In 2008, baobab dried fruit pulp was authorized in the EU as asafe food ingredient,[37] and later in the year was grantedGRAS (generally recognized as safe) status in the United States.[38]
InAngola, the dry fruit ofA. digitata is usually boiled, and the broth is used for juices or as the base for a type ofice cream known asgelado de múcua.[citation needed] InZimbabwe, the fruit ofA. digitata is eaten fresh or the crushed crumbly pulp is stirred intoporridge and drinks.[39] InTanzania, the dry pulp ofA. digitata is added tosugarcane to aidfermentation in brewing (beermaking).[40]
Some baobab species are sources offiber,dye, andfuel.Indigenous Australians used the native speciesA. gregorii for several products, making string from the root fibers and decorative crafts from the fruits.[43] Baobab oil from the seed is also used in cosmetics, particularly inmoisturizers.[44]
Baobab trees hold cultural and spiritual significance in many African societies. They are often the sites of communal gatherings, storytelling, and rituals.[45] An unusual baobab was the namesake ofKukawa, formerly the capital of theBornu Empire southwest ofLake Chad inCentral Africa.
In the novelThe 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 representNazism attempting to destroy the planet.[46]
^"Genus:Adansonia L."Germplasm Resources Information Network. United States Department of Agriculture. 12 November 2008. Archived fromthe original on 30 May 2010. Retrieved14 January 2011.
^writer, Staff (2024)."Baobab Trees".www.barbados.org. Barbados: Axses Systems Caribbean Inc. Retrieved11 March 2025.These two Baobab trees hold a well deserved place in the Barbados.org's "Seven Wonders of Barbados"!
^"GRIN Species Records ofAdansonia".Germplasm Resources Information Network. United States Department of Agriculture. Archived fromthe original on 24 September 2015. Retrieved14 January 2011.
^"Weavers breeding in baobabs". Animal Demography Unit, Department of Biological Sciences, University of Cape Town, South Africa. Archived fromthe original on 15 September 2015. Retrieved30 October 2014.
^Sidibe, M., et al.Baobab, Adansonia digitataL. Volume 4 ofFruits for the Future. International Centre for Underused Crops, 2002.
^abAmbrose-Oji, B., and Mughogho, N. 2007.Adansonia grandidieri Baill.Archived 7 April 2014 at theWayback Machine In: van der Vossen, H.A.M., and Mkamilo, G.S. (eds). PROTA 14: Vegetable oils/Oléagineux. PROTA, Wageningen, Netherlands.
^abAmbrose-Oji, B., and Mughogho, N. 2007.Adansonia za Baill.Archived 2 April 2015 at theWayback Machine In: van der Vossen, H.A.M., and Mkamilo, G.S. (eds). PROTA 14: Vegetable oils/Oléagineux. PROTA, Wageningen, Netherlands.
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