''Olea capensis'', the black ironwood,
is an African tree species in the olive family
Oleaceae
Oleaceae, also known as the olive 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. Green. 2004. "Oleaceae". pages 296-30 ...
. It is widespread in sub-Saharan Africa: from the east in
Somalia
Somalia, , Osmanya script: 𐒈𐒝𐒑𐒛𐒐𐒘𐒕𐒖; ar, الصومال, aṣ-Ṣūmāl officially the Federal Republic of SomaliaThe ''Federal Republic of Somalia'' is the country's name per Article 1 of thProvisional Constituti ...
,
Ethiopia
Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...
and
Sudan
Sudan ( or ; ar, السودان, as-Sūdān, officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is a country in Northeast Africa. It shares borders with the Central African Republic t ...
, south to the tip of
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
, and west to
Cameroon
Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...
,
Sierra Leone
Sierra Leone,)]. officially the Republic of Sierra Leone, is a country on the southwest coast of West Africa. It is bordered by Liberia to the southeast and Guinea surrounds the northern half of the nation. Covering a total area of , Sierra ...
and the islands of the
Gulf of Guinea
The Gulf of Guinea is the northeasternmost part of the tropical Atlantic Ocean from Cape Lopez in Gabon, north and west to Cape Palmas in Liberia. The intersection of the Equator and Prime Meridian (zero degrees latitude and longitude) is in the ...
, as well as
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
and the
Comoros
The Comoros,, ' officially the Union of the Comoros,; ar, الاتحاد القمري ' is an independent country made up of three islands in southeastern Africa, located at the northern end of the Mozambique Channel in the Indian Ocean. It ...
.
[ It occurs in bush, littoral scrub and evergreen forest.]
Other common names in English include ironwood, ironwood olive, East African olive and Elgon olive.
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 a romantic or sexual attraction or behavior toward both males and females, or to more than one gender. It may also be defined to include romantic or sexual attraction to people regardless of their sex or gender identity, whi ...
, 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 that i ...
in parks and garden
A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is ''control''. The garden can incorporate both ...
s.
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 reference book published annually, listing world ...
lists this tree as the world's heaviest wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...
, with a specific gravity
Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...
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 submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the hig ...
or dry earth. It is known for its tendency to sink in water, unlike other wood materials. It is also the 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
Woodturning is the craft of using a wood lathe with hand-held tools to cut a shape that is symmetrical around the axis of rotation. Like the potter's wheel, the wood lathe is a simple mechanism that can generate a variety of forms. The operator ...
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
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{{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