Sclerocarya birrea

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Sclerocarya birrea (Template:Langx Template:Angbr, meaning "hard", and Template:Lang Template:Angbr, "nut", in reference to the stone inside the fleshy fruit), commonly known as the marula, is a medium-sized deciduous fruit-bearing tree, indigenous to the miombo woodlands of Southern Africa, the Sudano-Sahelian range of West Africa, the savanna woodlands of East Africa and Madagascar.

Description

The tree is a single-stemmed species with a broad, spreading crown. It is distinguished by its grey mottled bark and can grow up to 18 meters tall, primarily in low altitudes and open woodlands. The distribution of this species throughout Africa and Madagascar has followed the Bantu in their migrations. There is some evidence of human domestication of marula trees, as trees found on farm lands tend to have larger fruit size.<ref>Template:Cite journal</ref>

The fruits are oblong or ovate, about 3–4 cm,<ref name="FAO1988"/> rarely attaining 5 cm,<ref name="NRC2008"/> and ripen between February and March or somewhat later into April; they have a light yellow skin (exocarp), with white flesh (mesocarp).<ref name="FAO1988"/>Template:Sfnp They fall to the ground when unripe and green in colour, and then ripen to a yellow colour on the ground.<ref name="FAO&Wickens1995"/>Template:Sfnp They are succulent and tart with a strong and distinctive flavour.<ref name="SAfrConsulate2002"/><ref name="FAO&Wickens1995"/>Template:Sfnp Inside a hard, thick-walled stone there are usually 2 or 3 seeds, though up to 4 seeds can be present,Template:Cn one in each cell or compartment. The kernel of the seed is edible. The seeds are closed in with plugs.<ref name="FAO1988"/><ref name="palmer&pitman1972"/> For commercial propagation, the seeds may be soaked or otherwise treated to loosen the plugs (opercula) in order to improve germination.<ref name="plantuse">Template:Cite web</ref>

The trees are dioecious, so that normally only female trees will fruit, but hermaphroditic production has been reported.<ref name="NRC2008"/> Male trees produce multiple male flowers on a terminal raceme. These have red sepals and petals, and about 20 stamens per flower. On rare occasions a male flower can produce a gynoecium, turning it bisexual. Female flowers grow individually on their own pedicel and have staminodes.<ref name=plantuse/> The leaves are alternate, compound, and imparipinnately divided. The leaflet shapes range from round to elliptical.

Taxonomy and etymology

Sclerocarya birrea is divided into three subspecies: subsp. birrea, subsp. afra and subsp. multifoliolata.<ref name="plantuse" /> These subspecies are differentiated by changes in leaf shape and size. Subsp. birrea is found in northern Africa, subsp. afra is found in southern Africa, and subsp. multifoliolata is only found in Tanzania.<ref name="plantuse" />

The generic name Sclerocarya is derived from the Ancient Greek words 'skleros' meaning 'hard' and 'karyon' meaning 'nut'. This refers to the hard pit of the fruit. The specific epithet 'birrea' comes from the common name 'birr', for this type of tree in Senegal and Gambia.<ref name="plantuse" /<ref name="CRC-quattrocchi1999"/> The marula belongs to the same family, Anacardiaceae, as the mango, cashew, pistachio and sumac, and is closely related to the genus Poupartia from Madagascar.

Common names

Common names include jelly plum, cat thorn, morula, cider tree, marula, maroola nut/plum,<ref name="CRC-quattrocchi1999"/> or elephant plum.<ref name="NRC2008"/><ref name="dwaf"/>

In South Africa, the Afrikaans names are Template:Lang.<ref name="NRC2008"/><ref name="dwaf">Template:Cite web</ref> Tribal names (generally Bantu) are Template:Lang in Venda,<ref name="CRC-quattrocchi1999"/> Template:Lang or<ref name="CRC-torkelson1995"/> Template:Lang, etc. in Shona.<ref name="CRC-quattrocchi1999"/>

In Zimbabwe, it is called Template:Lang in the Ndau dialect<ref name="CRC-torkelson1995"/> and Template:Lang,<ref name="FAO1988"/> Template:Lang in Northern Ndebele,<ref name="CRC-torkelson1995"/> var. Template:Lang Template:Refn

In Tanzania, it is known as Template:Lang, probably in Swahili.<ref name="FAO1988"/>

In Kenya, Template:Lang in Swahili and Digo language; Template:Lang in Oromo; Template:Lang in Maasai; Template:Lang in Pökoot; Template:Lang in Tugen.<ref name="beentje1994"/>

In Namibia, it is known in the Herero and the closely related Ovambo language as Template:Lang.<ref name="NRC2008"/><ref name="palmer&pitman1972"/><ref name="CRC-quattrocchi1999"/>

This list is still not exhaustive.

Subspecies

Three subspecies are accepted:<ref name = POWO/>

Sclerocarya birrea subsp. afra Template:Small – Kenya to Namibia and KwaZulu-Natal, Madagascar, and Mayotte
Sclerocarya birrea subsp. birrea – West Africa to Ethiopia and Tanzania
Sclerocarya birrea subsp. multifoliolata Template:Small – Tanzania

Uses

Traditional uses

The fruit is traditionally used for food in Africa, and has considerable socioeconomic importance.<ref name="NRC2008"/> The fruit juice and pulp are mixed with water and stored in a container over 1–3 days of fermentation to make marula beer, a traditional alcoholic beverage.<ref>Template:Cite web</ref>

The edible kernel inside the hard nutshell is difficult to extract but is delicious and is eaten by children; these "nuts" are also the staple that some hunter-gatherer tribes subsist on in the winter season.<ref name="FAO1988"/>

In Namibia, the Ovambo people call the liqueur or wine made from marula Template:Lang or Template:Lang,<ref name="mans2006"/><ref name="FAO2004"/><ref name="nghitevelekwa2020"/>Template:Refn perhaps distinguishable from a weaker beer product.<ref name="mans2006"/>Template:Efn The juice (Template:Langx) and cooking oil (Template:Lang Template:Refn) are also harvested.<ref name="FAO2004"/>

Marula oil is used topically to moisturise the skin, and also an edible oil in the diet of San people in Southern Africa.<ref name="engelter&wehmeye1970"/><ref name="shackleton-etal2002"/> The marula tree is protected in South Africa.<ref name="dwaf" />

In South Africa, the Amarula cream liqueur is made from the fruit.<ref name="SAfrConsulate2002"/> There are also Template:Lang (moonshine) distilled from the morula, which is mentioned in the writings of South African writer Herman Charles Bosman.Template:Refn

Commercial uses

On an industrial level the fruit of the marula tree is collected from the wild by members of rural communities on whose land the trees grow. This harvest and sale of fruit only occur over two to three months, but is an important source of income to poor rural people, especially women.<ref>Template:Cite journal</ref> The fruit is delivered to processing plants where fruit pulp, pips, kernels and kernel oil are extracted and stored for processing throughout the year.Template:Citation needed

Uses by other species

The marula fruit is eaten by various animals in Southern Africa. Giraffes, rhinoceroses and elephants all browse on the marula tree, with elephants in particular being a major consumer. Elephants eat the bark, branches and fruits of the marula, which may limit the spread of the trees. The damaged bark, due to browsing, can be used to identify marula trees as elephants preferentially target them. Elephants distribute marula seeds in their dung.<ref name="morris">Template:Cite journal</ref> In the documentary Animals Are Beautiful People by Jamie Uys, released in 1974, some scenes portray elephants, ostriches, warthogs and baboons allegedly becoming intoxicated from eating fermented marula fruit, as do reports in the popular press.<ref>Template:Cite web</ref> While the fruit is commonly eaten by elephants, the animals would need a huge amount of fermented marulas to have any effect on them,<ref name="morris" /> and other animals prefer the ripe fruit.

The marula fruit has been suggested to be the food of choice for the ancestral forest-dwelling form of the fruit fly Drosophila melanogaster, which was much more selective about which fruit they preferred than the flies that have self-domesticated to live near to humans. The ancestral fruit flies are triggered by the ester ethyl isovalerate in the marula fruit.<ref>Template:Cite journal</ref>