''Olea capensis'', the black ironwood, is an African tree species in the olive family

Oleaceae Oleaceae, also known as the olive family or sometimes the lilac family, is a taxonomic family of flowering shrubs, trees, and a few lianas in the order Lamiales. It presently comprises 28 genera, one of which is recently extinct.Peter S. Gree ...

. It is widespread in sub-Saharan Africa: from the east in

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Ethiopia Ethiopia, officially the Federal Democratic Republic of Ethiopia, is a landlocked country located in the Horn of Africa region of East Africa. It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east, Ken ...

and

Sudan Sudan, officially the Republic of the Sudan, is a country in Northeast Africa. It borders the Central African Republic to the southwest, Chad to the west, Libya to the northwest, Egypt to the north, the Red Sea to the east, Eritrea and Ethiopi ...

, south to the tip of

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, and west to

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and the islands of the

Gulf of Guinea The Gulf of Guinea (French language, French: ''Golfe de Guinée''; Spanish language, Spanish: ''Golfo de Guinea''; Portuguese language, Portuguese: ''Golfo da Guiné'') is the northeasternmost part of the tropical Atlantic Ocean from Cape Lopez i ...

, as well as

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and the

Comoros The Comoros, officially the Union of the Comoros, is an archipelagic country made up of three islands in Southeastern Africa, located at the northern end of the Mozambique Channel in the Indian Ocean. Its capital and largest city is Moroni, ...

. It occurs in bush, littoral scrub and evergreen forest. Other common names in English include ironwood, ironwood olive, East African olive and Elgon olive. Giant Ironwood Tree - Olea capensis macrocarpa - Newlands Forest - Cape Town 1

Giant Ironwood Tree - Olea capensis macrocarpa - Newlands Forest - Cape Town 1

Description

The black ironwood is a bushy shrub, or a small to medium-sized tree, up to in height, occasionally reaching . *Bark: light grey, becoming dark grey and vertically fissured with age; a characteristic blackish gum is exuded from bark wounds. *Leaves: light to dark green and glossy above and paler green below; petiole often purplish, 0.3–1.7 cm long; lanceolate-oblong to almost circular, 3–10 x 1.5–5 cm. *Flowers: white or cream and sweetly scented, small and in many flowered axillary or terminal heads,

bisexual Bisexuality is romantic attraction, sexual attraction, or sexual behavior toward both males and females. It may also be defined as the attraction to more than one gender, to people of both the same and different gender, or the attraction t ...

, 3–15 cm long. *Fruit: when ripe they are somewhat succulent purplish drupes; ovoid up to 2 x 1 cm.

Subspecies

The species has been divided into 3 subspecies: * ''Olea capensis'' subsp. ''macrocarpa'': flowers in lax heads, fruits oblong to elliptic. * ''Olea capensis'' subsp. ''capensis'': flowers in dense heads, leaves very variable, apex often rounded, and fruits almost spherical to oblong elliptic. * ''Olea capensis'' subsp. ''enervis'': leaves usually broadly elliptic, apex tapering.

Uses

Food

''Olea capensis'' has masses of sweetly scented bisexual flowers, that produce large edible fruits.

Timber

The wood of the tree is very hard, fine grained, and heavy, and although difficult to work, it is widely used for art and artifacts.

Gardens

''Olea capensis'' is cultivated as an

ornamental tree Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...

in parks and gardens. The

Guinness Book of World Records ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a British reference book published annually, listi ...

lists this tree as the world's heaviest wood, with a

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

of 1.49, similar to that of

anthracite Anthracite, also known as hard coal and black coal, is a hard, compact variety of coal that has a lustre (mineralogy)#Submetallic lustre, submetallic lustre. It has the highest carbon content, the fewest impurities, and the highest energy densit ...

or dry earth. It is known for its tendency to sink in water, unlike other wood materials. It is also one of the world's hardest woods according to the

Janka hardness test The Janka hardness test (; ), created by Austrian-born American researcher Gabriel Janka (1864–1932), measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an steel ball halfway into a sample ...

. The timber has a good abrasion resistance and is very strong. It is an excellent turnery wood, and is used for a wide range of decorative items.

Gallery

Olea capensis Ironwood tree flowers.JPG, Olea capensis01.jpg, Olea capensis03.jpg, Olea capensis04.jpg,

References

External links

* * * * {{Taxonbar, from=Q568254 capensis Trees of Africa Fodder Wood Drought-tolerant trees Fruits originating in Africa Garden plants of Africa Ornamental trees Plants described in 1753 Taxa named by Carl Linnaeus Afromontane flora