Adansonia digitata L.

Common Name and Growth Habit

Adansonia digitata L., commonly known as the African baobab, is a large tree that typically grows as a solitary individual, forming a prominent, distinctive feature of savanna and scrubland vegetation.

Mature Height

Mature trees reach heights of 5 to 25 metres (16 to 82 feet).

Trunk Shape

Their trunks are characteristically very broad, shaped as either fluted or cylindrical, and often have a buttressed, spreading base.

Trunk Diameter and Structure

Trunks can reach diameters of 10 to 14 m (33 to 46 ft), and many are formed from multiple stems fused around a hollow core.

Hollow Core Formation

While hollow cores in most tree species form from decay of the oldest inner trunk wood, in the largest, oldest African baobabs, the hollow core typically forms when three to eight stems sprout from the same root system and fuse into a circle around an open center.

Bark and Branch Characteristics

The bark is grey and usually smooth, and main branches can grow to be very large.

Deciduous Trait

All baobabs are deciduous: they drop all their leaves during the dry season, and remain leafless for approximately eight months each year.

Leaf Structure by Maturity

Mature African baobabs produce palmately compound leaves, with five to seven, and sometimes up to nine, leaflets; seedlings and new regenerating shoots may grow simple leaves instead.

Leaf Development Transition

The shift from simple to compound leaves occurs gradually with age. Unlike most other Adansonia species, African baobabs retain simple leaves for much longer as they mature.

Leaflet Characteristics

Leaflets range from stalkless (sessile) to short-stalked, and vary in size.

Basic Flower and Fruit Traits

Flowers are large, white, and hang from stalks. Fruits are rounded with a thick outer shell.

Flowering Period

Flowering can occur in both the dry and wet seasons.

Flower Bud Traits

Flower buds are rounded with a cone-shaped tip.

Flower Arrangement and Stalk Length

Flowers are showy; they sometimes grow in pairs, but most often grow singly at the end of a hanging stalk that measures 15 to 90 centimetres (6 to 35+1⁄2 inches) in length.

Calyx Characteristics

The calyx usually has five (sometimes three) green triangular bent-back sepals, with a cream-colored, hairy inner surface.

Petal Characteristics

Petals are white, roughly equal in width and length (reaching up to 8 cm, or 3 in), and crumpled when in bud.

Flower Longevity

Flowers open in the late afternoon and remain open and fertile for only one night.

Flower Scent Changes

Fresh flowers have a sweet scent, but after roughly 24 hours, they begin to turn brown and release a carrion odor.

Androecium Structure

The androecium is white, formed of a 3–6 cm (1+1⁄4–2+1⁄4 in) long tube of fused stamens (called a staminal tube), surrounded by unfused, free filaments that are 3 to 5 cm long.

Stamen Count

A single flower has a large number of stamens, ranging from 720 to 1600, with some reports recording up to 2000 stamens per flower.

Style and Stigma Traits

Styles are white, grow through the staminal tube and extend past it, and are typically bent at a right angle, topped with an irregular stigma.

Pollen Characteristics

Pollen grains are spherical with surface spikes, a trait typical of the Malvaceae family, and have a diameter of around 50 microns.

Genus Fruit Traits

All Adansonia species produce large, rounded, indehiscent fruits that can grow up to 25 cm (10 in) long, with a woody outer shell.

African Baobab Fruit Shape

African baobab fruits vary widely in shape, ranging from nearly round to cylindrical.

Fruit Shell Thickness

The fruit shell is 6–10 millimetres (1⁄4–3⁄8 in) thick.

Fruit Pulp Characteristics

Inside the shell is a fleshy, light beige pulp; as the pulp dries, it hardens into a crumbly powder.

Seed Physical Traits

Seeds are hard, kidney-shaped, with a 0.06-mm thick seed coat.

Seed Dormancy Triggers

They have long-term dormancy, and only germinate after passing through an animal’s digestive tract or after exposure to fire.

Germination Requirement

This is thought to occur because the seed coat needs to be cracked or thinned to allow water penetration before germination can begin.

Habitat and Climatic Preferences

The African baobab is associated with tropical savannas, and grows in drier climates. It is sensitive to waterlogging and frost, and does not grow in areas with deep sand.

Native Latitudinal Range

It is native to mainland Africa, occurring between the latitudes 16° N and 26° S.

Presence in Arabian Peninsula

Some sources list it as introduced to Yemen and Oman, while others consider it native to those areas.

Non-African Introductions

It has also been introduced to many other regions, including Australia and Asia.

African Distribution Limits

In Africa, the northern limit of its natural distribution is tied to rainfall patterns; it only extends naturally into the Sahel along the Atlantic coast and in the Sudanian savanna, and its presence in the Atlantic Sahel may be the result of spread after cultivation. It is very rare in Central Africa, and only grows in the far north of South Africa.

East African Habitat Range

In East Africa, it also grows in shrublands and along the coast.

Southern African Habitat Range

In Angola and Namibia, it grows in woodlands and coastal regions in addition to savannas.

Native Country Distribution

It is native to Mauritania, Senegal, Guinea, Sierra Leone, Mali, Burkina Faso, Ghana, Togo, Benin, Niger, Nigeria, northern Cameroon, Chad, Sudan, Republic of the Congo, DR Congo (formerly Zaire), Eritrea, Ethiopia, southern Somalia, Kenya, Tanzania, Zambia, Zimbabwe, Malawi, Mozambique, Angola, São Tomé, Príncipe, Annobon, South Africa (restricted to Limpopo province, north of the Soutpansberg mountain range), Namibia, and Botswana.

Introduced Country Distribution

It is an introduced species in Java, Nepal, Sri Lanka, the Philippines, Jamaica, Puerto Rico, Haiti, the Dominican Republic, Venezuela, the Seychelles, the Comoros, India, and the Chinese provinces of Guangdong, Fujian, and Yunnan.

Planted Location in Malaysia

It has also been planted along streets in Penang, Malaysia.

Introduction to Madagascar

Arab traders introduced it to northwestern Madagascar, where it has often been planted at the center of villages.

Deciduous Cycle Restatement

As a deciduous species, African baobab loses its leaves in the dry season and remains leafless for about eight months annually.

Fire Adaptations

It occurs mostly in fire-prone savanna habitats, and has several adaptations to survive frequent fires: a thick, fire-resistant bark and thick-shelled fruit. Trees older than roughly 15 years have bark thick enough to withstand the heat of most savanna fires, while younger trees can resprout after a fire. The thick fruit shell may also help protect seeds.

Pollinators

Pollination of African baobab is primarily done by fruit bats; in West Africa, the main pollinators are the straw-coloured fruit bat, Gambian epauletted fruit bat, and Egyptian fruit bat. Flowers are also visited by galagos and multiple types of insect.

Seed Viability Traits

Thanks to their hard outer coat, baobab seeds tolerate drying and remain viable for long periods. Many animal species eat baobab fruit, and germination is more successful when seeds have passed through an animal’s digestive tract or been exposed to fire.

Animal Seed Dispersal

Elephants and baboons are the main seed dispersal agents, so seeds can be spread over long distances.

Water Seed Dispersal

The fruit is buoyant, and the seeds are waterproof, so African baobab seeds can also be dispersed by water.

Reproductive Biology Notes

Some parts of the species’ reproductive biology are not yet fully understood, but it is thought that pollen from a separate individual tree is required to produce fertile seed.

Self-Incompatibility Trait

Isolated trees without access to outside pollen do form fruit, but abort the fruit at a later development stage. The presence of some very isolated individual trees is thought to stem from the species’ ability to disperse seeds over long distances combined with its self-incompatibility.

Ecological Role

The African baobab’s fruit, bark, roots, and leaves are a key food source for many animals, and the trees themselves provide important shade and shelter.

Human Traditional Uses Overview

Humans have traditionally used African baobab as a source of food, water, traditional medicine, and shelter. It is a traditional food plant in Africa, but remains little-known outside of the continent.

Adanson's Assessment of Baobab

The 18th-century botanist Michel Adanson, after whom the genus is named, concluded that baobabs are “probably the most useful tree in all” of the species he studied. Adanson drank baobab juice twice a day while in Africa, and believed it helped him maintain good health.

Medicinal Property Note

A modern field guide notes that the juice may help cure diarrhoea.

Edible Plant Parts

The roots and fruit are edible.

Potential Nutritional and Development Uses

It has been suggested that baobab fruit could help improve nutrition, increase food security, support rural development, and aid sustainable land management.

Sudanese Juice Preparation

In Sudan, where the tree is called tebeldi, people make tabaldi juice by soaking and dissolving the dry fruit pulp in water, which is locally called gunguleiz.

Trunk Water Extraction

Water can also be extracted from the trunks of some trees.

Leaf Use as Food

Baobab leaves can be eaten as a relish. Young fresh leaves are cooked into a sauce, and are sometimes dried and ground into powder.

West African Leaf Powder Use

This powder is called lalo in Mali, and is sold in many village markets across West Africa.

Nigerian Leaf Soup Use

The leaves are used to make a soup called miyan kuka in Northern Nigeria, and are rich in phytochemicals and minerals.

Seed Food Uses

Seeds can be pounded into flour, or processed to extract cooking oil.

Livestock Forage Uses

During the dry season, baobab leaves are sometimes used as forage for ruminants. The oilmeal that remains after oil extraction can also be used as animal feed.

Fruit Storage Trait

Whole baobab fruit, or just the fruit pulp, can be stored for months in dry conditions.

Bark Fibre Use

Bark fibre can be used to make cloth.

Elephant Baobab Use During Drought

During droughts, elephants eat the water-rich wood beneath the baobab’s bark.