Prunus africana
Encyclopedia
Prunus africana, or Red Stinkwood (see the names, below, for more), is an evergreen tree
native to the montane
regions of Sub-Saharan Africa
and the Islands of Madagascar
, Sao Tome
, Fernando Po
and Grande Comore
at about 900–3400 m. of altitude. The mature tree is 10–25 m. high, open-branched and often pendulous in forest, shorter and with a round crown of 10–20 m. diameter in grassland. It requires a moist climate, 900–3400 mm annual rainfall, and is moderately frost-tolerant.
The bark is black to brown, corrugated or fissured and scaly, fissuring in a characteristic rectangular pattern. The leaves
are alternate, simple, long (8–20 cm.), elliptic, bluntly or acutely pointed, glabrous and dark green above, pale green below, with mildly serrate margins. A central vein is depressed on top, prominent on the bottom. The 2-cm petiole
is pink or red. The flower
s are androgynous, 10-20 stamen
s, insect-pollinated, 3–8 cm., greenish white or buff, and are distributed in 70-mm axillary
raceme
s. The plant flowers October through May. The fruit
is red to brown, 7–13 mm., wider than long, two-lobed with a seed in each lobe. It grows in bunches ripening September through November, several months after pollination.
As with other members of the genus Prunus
, Prunus africana possesses extrafloral nectaries that provide anti-herbivore insects with a nutrient source in return for protecting the foliage.
The fruit is too bitter to be of interest to man; however, it is a favored food supply for many animals, who spread the seeds. Dian Fossey
reports of the Mountain Gorilla
: "The northwestern slopes of Visoke offered several ridges of Pygeum africanum .... The fruits of this tree are highly favored by gorillas." East African Mammals reports that stands of Pygeum are the habitat of the rare Carruther's Mountain Squirrel
and asserts that "This forest type tends to have a rather broken canopy with many trees smothered in climbers and dense tangles of undergrowth."
It is currently protected under appendix II of CITES.
An extract, pygeum, an herbal remedy prepared from the bark of Prunus africana, is used as an alternative medicine in patients with benign prostatic hyperplasia
(BPH) though clinical trials have not yet been conducted. It has shown positive results in in vitro
studies and mouse models of prostate cancer.
The collection of mature bark for this purpose and for other medical uses has resulted in the species becoming endangered. Prunus africana continues to be taken from the wild. Plantecam Medicam deserves credit for
attempting sustainable bark harvesting by removing opposing quarters of trunk bark rather than girdling the trees. However, quotas have been awarded by the Forestry Department without adequate forest inventories due to some harvesters, spurred on by the high price per kilogram of bark, removing too much of the bark in an unsustainable manner. In the 1990s it was estimated that 35,000 debarked trees were being processed annually. The growing demand for the bark has led to the cultivation of the tree for its medicinal uses.
The timber is a hardwood employed in the manufacture of axe and hoe handles, utensils, wagons, floors, chopping blocks, carving, bridge decks and furniture. The wood is tough, heavy, straight-grained and pink, with a pungent bitter-almond smell when first cut, turning mahogony and odorless later.
during his now famous first European exploration of the Cameroon Range
, with Richard Francis Burton
and Alfred Saker
, in 1861. A letter from Mann to the Linnean Society of London
, read by William Jackson Hooker
, then Director of the Royal Botanic Gardens, Kew
, on June 5, 1862, describes the naming of the peaks of the Cameroon Range (such as Mount Victoria, later Mount Cameroon) and the collection of specimens there. The latter were shipped back to Kew for classification, which was duly performed by Hooker and his son, Joseph Dalton Hooker
, who had the responsibility of publishing them, as William died in 1865.
When the publication came out the Hookers had named the plant Pygeum africanum, followed by the designation "n. sp.", an abbreviation for nova species. The habitat is listed as "Cameroons Mountains, alt. 7000-7500 feet", which was above the tropical forest and in the alpine grasslands. Hooker notes that another specimen had been "gathered in tropical Eastern Africa" at 3000 feet by Dr. Kirk on an expedition of David Livingstone
.
The first publication of the synonym in 1864 had been preceded by publication of the bare name in 1863 in a book by Richard Francis Burton
. Evidently Hooker had already made the contents of J. Proc. Linn. Soc., Bot. 7 for 1864 available to some, as Burton mentions the volume and Mann's letter in 1863.
Hooker gives scant hint of why he chose "pygeum"; however, what he does say indicates it was common knowledge among botanists. Kirk's specimen fruit was "a much depressed sphere." By this he undoubtedly meant to reference Joseph Gaertner
's genus, Pygeum Gaertn., which innovates pygeum from a Greek word, πυγή, "rump, buttock", because the two lobes of the fruit resemble the human gluteus maximus muscles.
In 1965 Cornelis Kalkman moved Pygeum to Prunus and this classification has the authority for now. However, a recent cladistic study notes of Pygeum: "its relationships to Prunus remain to be tested by molecular cladistics."
'Muiri', in Ganda 'Entasesa'or 'Ngwabuzito', in Xhosa
'uMkakase', in Zulu
'Inyazangoma-elimnyama' and in Afrikaans
'Rooistinkhout'.
two core samples from montane Mubindi Swamp in Uganda
. The swamp is a catchment at 2100 m. altitude between mountain ridges. It is a "moist lower montane forest" in Bwindi Forest National Park
. The investigators found that montane Prunus, represented by currently growing Prunus africana, has been in the catchment continuously since their Pollen Zone MB6.1, dated approximately 43000-33000 ybp.
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
native to the montane
Montane
In biogeography, montane is the highland area located below the subalpine zone. Montane regions generally have cooler temperatures and often have higher rainfall than the adjacent lowland regions, and are frequently home to distinct communities of plants and animals.The term "montane" means "of the...
regions of Sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...
and the Islands of Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, Sao Tome
São Tomé
-Transport:São Tomé is served by São Tomé International Airport with regular flights to Europe and other African Countries.-Climate:São Tomé features a tropical wet and dry climate with a relatively lengthy wet season and a short dry season. The wet season runs from October through May while the...
, Fernando Po
Bioko
Bioko is an island 32 km off the west coast of Africa, specifically Cameroon, in the Gulf of Guinea. It is the northernmost part of Equatorial Guinea with a population of 124,000 and an area of . It is volcanic with its highest peak the Pico Basile at .-Geography:Bioko has a total area of...
and Grande Comore
Grande Comore
Grande Comore is an island in the Indian Ocean off the coast of Africa. It is the largest island in the Comoros nation. Most of its population is of the Comorian ethnic group. Its population as of 2006 is about 316,600. The island's capital is Moroni, which is also the national capital...
at about 900–3400 m. of altitude. The mature tree is 10–25 m. high, open-branched and often pendulous in forest, shorter and with a round crown of 10–20 m. diameter in grassland. It requires a moist climate, 900–3400 mm annual rainfall, and is moderately frost-tolerant.
The bark is black to brown, corrugated or fissured and scaly, fissuring in a characteristic rectangular pattern. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are alternate, simple, long (8–20 cm.), elliptic, bluntly or acutely pointed, glabrous and dark green above, pale green below, with mildly serrate margins. A central vein is depressed on top, prominent on the bottom. The 2-cm petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
is pink or red. The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are androgynous, 10-20 stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s, insect-pollinated, 3–8 cm., greenish white or buff, and are distributed in 70-mm axillary
Axillary
Axillary means "related to the axilla "."Axillary" may refer to:* Axillary artery* Axillary vein* Axillary nerve* Axillary bud...
raceme
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
s. The plant flowers October through May. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is red to brown, 7–13 mm., wider than long, two-lobed with a seed in each lobe. It grows in bunches ripening September through November, several months after pollination.
Ecology
Prunus
Prunus is a genus of trees and shrubs, which includes the plums, cherries, peaches, apricots and almonds. There are around 430 species spread throughout the northern temperate regions of the globe. Many members of the genus are widely cultivated for fruit and ornament.-Botany:Members of the genus...
, Prunus africana possesses extrafloral nectaries that provide anti-herbivore insects with a nutrient source in return for protecting the foliage.
The fruit is too bitter to be of interest to man; however, it is a favored food supply for many animals, who spread the seeds. Dian Fossey
Dian Fossey
Dian Fossey was an American zoologist who undertook an extensive study of gorilla groups over a period of 18 years. She studied them daily in the mountain forests of Rwanda, initially encouraged to work there by famous anthropologist Louis Leakey...
reports of the Mountain Gorilla
Mountain Gorilla
The Mountain Gorilla is one of the two subspecies of the Eastern Gorilla. There are two populations. One is found in the Virunga volcanic mountains of Central Africa, within three National Parks: Mgahinga, in south-west Uganda; Volcanoes, in north-west Rwanda; and Virunga in the eastern Democratic...
: "The northwestern slopes of Visoke offered several ridges of Pygeum africanum .... The fruits of this tree are highly favored by gorillas." East African Mammals reports that stands of Pygeum are the habitat of the rare Carruther's Mountain Squirrel
Carruther's Mountain Squirrel
The Carruther's Mountain Squirrel is a species of rodent in the Sciuridae family.It is found in Burundi, Democratic Republic of the Congo, Rwanda, and Uganda.Its natural habitat is subtropical or tropical moist montanes....
and asserts that "This forest type tends to have a rather broken canopy with many trees smothered in climbers and dense tangles of undergrowth."
It is currently protected under appendix II of CITES.
Uses
Traditionally used for fevers, malaria, wound dressing, arrow poison, stomach pain, purgative, kidney disease, appetite stimulant, gonorrhoea, and insanity.Benign prostatic hyperplasia
Benign prostatic hyperplasia also known as benign prostatic hypertrophy , benign enlargement of the prostate , and adenofibromyomatous hyperplasia, refers to the increase in size of the prostate....
(BPH) though clinical trials have not yet been conducted. It has shown positive results in in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
studies and mouse models of prostate cancer.
The collection of mature bark for this purpose and for other medical uses has resulted in the species becoming endangered. Prunus africana continues to be taken from the wild. Plantecam Medicam deserves credit for
attempting sustainable bark harvesting by removing opposing quarters of trunk bark rather than girdling the trees. However, quotas have been awarded by the Forestry Department without adequate forest inventories due to some harvesters, spurred on by the high price per kilogram of bark, removing too much of the bark in an unsustainable manner. In the 1990s it was estimated that 35,000 debarked trees were being processed annually. The growing demand for the bark has led to the cultivation of the tree for its medicinal uses.
The timber is a hardwood employed in the manufacture of axe and hoe handles, utensils, wagons, floors, chopping blocks, carving, bridge decks and furniture. The wood is tough, heavy, straight-grained and pink, with a pungent bitter-almond smell when first cut, turning mahogony and odorless later.
Discovery and classification
The name of the remedy, pygeum, comes from the name of the plant, which was discovered to botany by Gustav MannGustav Mann
Gustav Mann was a German botanist who led expeditions in West Africa and was also a gardener at the Royal Botanic Gardens, Kew.Born in Hanover in 1836, he was chosen by William Jackson Hooker, Director of the Royal Botanic Gardens, Kew, to take part in William Balfour Baikie's expedition to West...
during his now famous first European exploration of the Cameroon Range
Cameroon line
The Cameroon line is a chain of volcanoes.It includes islands in the Gulf of Guinea and mountains that extend along the border region of eastern Nigeria and western Cameroon, from Mount Cameroon on the Gulf of Guinea north and east towards Lake Chad....
, with Richard Francis Burton
Richard Francis Burton
Captain Sir Richard Francis Burton KCMG FRGS was a British geographer, explorer, translator, writer, soldier, orientalist, cartographer, ethnologist, spy, linguist, poet, fencer and diplomat. He was known for his travels and explorations within Asia, Africa and the Americas as well as his...
and Alfred Saker
Alfred Saker
Alfred Saker was a British missionary who founded the Cameroon city of Victoria, now Limbé , in 1858.He translated the Bible into Duala between 1862 and 1872....
, in 1861. A letter from Mann to the Linnean Society of London
Linnean Society of London
The Linnean Society of London is the world's premier society for the study and dissemination of taxonomy and natural history. It publishes a zoological journal, as well as botanical and biological journals...
, read by William Jackson Hooker
William Jackson Hooker
Sir William Jackson Hooker, FRS was an English systematic botanist and organiser. He held the post of Regius Professor of Botany at Glasgow University, and was the first Director of the Royal Botanic Gardens, Kew. He enjoyed the friendship and support of Sir Joseph Banks for his exploring,...
, then Director of the Royal Botanic Gardens, Kew
Royal Botanic Gardens, Kew
The Royal Botanic Gardens, Kew, usually referred to as Kew Gardens, is 121 hectares of gardens and botanical glasshouses between Richmond and Kew in southwest London, England. "The Royal Botanic Gardens, Kew" and the brand name "Kew" are also used as umbrella terms for the institution that runs...
, on June 5, 1862, describes the naming of the peaks of the Cameroon Range (such as Mount Victoria, later Mount Cameroon) and the collection of specimens there. The latter were shipped back to Kew for classification, which was duly performed by Hooker and his son, Joseph Dalton Hooker
Joseph Dalton Hooker
Sir Joseph Dalton Hooker OM, GCSI, CB, MD, FRS was one of the greatest British botanists and explorers of the 19th century. Hooker was a founder of geographical botany, and Charles Darwin's closest friend...
, who had the responsibility of publishing them, as William died in 1865.
When the publication came out the Hookers had named the plant Pygeum africanum, followed by the designation "n. sp.", an abbreviation for nova species. The habitat is listed as "Cameroons Mountains, alt. 7000-7500 feet", which was above the tropical forest and in the alpine grasslands. Hooker notes that another specimen had been "gathered in tropical Eastern Africa" at 3000 feet by Dr. Kirk on an expedition of David Livingstone
David Livingstone
David Livingstone was a Scottish Congregationalist pioneer medical missionary with the London Missionary Society and an explorer in Africa. His meeting with H. M. Stanley gave rise to the popular quotation, "Dr...
.
The first publication of the synonym in 1864 had been preceded by publication of the bare name in 1863 in a book by Richard Francis Burton
Richard Francis Burton
Captain Sir Richard Francis Burton KCMG FRGS was a British geographer, explorer, translator, writer, soldier, orientalist, cartographer, ethnologist, spy, linguist, poet, fencer and diplomat. He was known for his travels and explorations within Asia, Africa and the Americas as well as his...
. Evidently Hooker had already made the contents of J. Proc. Linn. Soc., Bot. 7 for 1864 available to some, as Burton mentions the volume and Mann's letter in 1863.
Hooker gives scant hint of why he chose "pygeum"; however, what he does say indicates it was common knowledge among botanists. Kirk's specimen fruit was "a much depressed sphere." By this he undoubtedly meant to reference Joseph Gaertner
Joseph Gaertner
Joseph Gaertner was a German botanist, best known for his work on seeds, De Fructibus et Seminibus Plantarum ....
's genus, Pygeum Gaertn., which innovates pygeum from a Greek word, πυγή, "rump, buttock", because the two lobes of the fruit resemble the human gluteus maximus muscles.
In 1965 Cornelis Kalkman moved Pygeum to Prunus and this classification has the authority for now. However, a recent cladistic study notes of Pygeum: "its relationships to Prunus remain to be tested by molecular cladistics."
Names
Prunus africana also goes by the following common names; Pygeum, Iron Wood, (Red) Stinkwood, African Plum, African Prune, African Cherry, Bitter Almond. In other languages where it grows it is known as; in Amharic 'tikur inchet', in Chagga 'Mkonde-konde', in KikuyuGikuyu language
Gikuyu or Kikuyu is a language of the Bantu family spoken primarily by the Kikuyu people of Kenya. Numbering about 6 million , they are the largest ethnic group in Kenya. Gikuyu is spoken in the area between Nyeri and Nairobi. Gikuyu is one of the five languages of the Thagichu subgroup of the...
'Muiri', in Ganda 'Entasesa'or 'Ngwabuzito', in Xhosa
Xhosa language
Xhosa is one of the official languages of South Africa. Xhosa is spoken by approximately 7.9 million people, or about 18% of the South African population. Like most Bantu languages, Xhosa is a tonal language, that is, the same sequence of consonants and vowels can have different meanings when said...
'uMkakase', in Zulu
Zulu language
Zulu is the language of the Zulu people with about 10 million speakers, the vast majority of whom live in South Africa. Zulu is the most widely spoken home language in South Africa as well as being understood by over 50% of the population...
'Inyazangoma-elimnyama' and in Afrikaans
Afrikaans
Afrikaans is a West Germanic language, spoken natively in South Africa and Namibia. It is a daughter language of Dutch, originating in its 17th century dialects, collectively referred to as Cape Dutch .Afrikaans is a daughter language of Dutch; see , , , , , .Afrikaans was historically called Cape...
'Rooistinkhout'.
Palaeobotanic evidence
A 1994/1995 study published in 1997 by Marchant and Taylor did a pollen analysis on and radiocarbon datedRadiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
two core samples from montane Mubindi Swamp in Uganda
Uganda
Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...
. The swamp is a catchment at 2100 m. altitude between mountain ridges. It is a "moist lower montane forest" in Bwindi Forest National Park
Bwindi Impenetrable National Park
Bwindi Impenetrable National Park is located in southwestern Uganda in East Africa. The park is part of the Bwindi Impenetrable Forest, and is situated along the Democratic Republic of Congo border next to the Virunga National Park and on the edge of the western Great Rift Valley...
. The investigators found that montane Prunus, represented by currently growing Prunus africana, has been in the catchment continuously since their Pollen Zone MB6.1, dated approximately 43000-33000 ybp.