General Info

Tree may reach 40m high.  Simple Leaves are hairless.  5-merous, bisexual and actinomorphic Flowers occur singly or in axillary racemes.  Fruit is a spherical drupe with small Seeds.

Description

Prunus africana, Pygeum africanum.

RSA Tree No. 147.

Common names: Red Stinkwood, African Almond, Bitter Almond, Wild Almond, African cherry.

Family: Rosaceae (includes the rose, apples, pears, peaches, apricots, and strawberries).  There are 90+ genera and nearly 5 000 species.  This family is usually perennial.  Local genera that are trees include Leucosidea and Prunus).  Leaves are usually spirally arranged and can be simple or pinnately compound. Spines may be present on the midrib and rachis of compound leaves.  Leaf/leaflet margins are usually serrate and stipules are present.  Flowers are impressive, actinomorphic, bisexual and bracteate.  Sepals and Petals both have 5 lobes and, together with the numerous Stamens are fused at their bases.  Stamens, petals and sepals are in a hypanthium (the cup-like receptacle derived usually from the fusion of floral envelopes and androecium, and on which are seemly borne calyx, corolla and stamens).  The Fruits are various.  Some Seeds may release cyanide if digested.

Name derivation: Prunus – Latin name for plumb tree.  africana from AfricaThe genus Prunus includes almonds, apricots, cherries, plumbs, peaches and nectarines.  Prunus africana is the only indigenous species in the RSA.

Conservation Status: Vulnerable 2009.  This is influenced by over exploitation of bark for traditional medicine.  In Cameroon, Madagascar, DRC, Kenya and Uganda the bark is harvested and exported.  This increases the problem.  The quantity exploited annually for export to Europe, Japan and the USA is between 3 200 – 4 900 tons.  This is the largest volume of any African medicinal plant in international trade.  Bark extracts are used to treat prostate hypertrophy.  The population trend is Decreasing.

Tree

This Tree may reach 40m high but is usually about half this height.  The Trunk is straight, rough and dark brown.  It may reach a diameter of up to 1m.  Branches are brown and corky. Bark becomes very rough and cracks into blocks.  Buds are covered with imbricate (having regularly arranged, overlapping edges, as roof tiles) scales.

Leaves

The Leaves on this evergreen tree are simple, elliptical or lance-shaped, alternatively arranged and up to 15 x 6cm.  Leaves lack silky hairs.  Glands may be visible at the base.  Leaves are shiny, dark green and glossy above and lighter green below.  Crushed leaves smell of almonds. The hairless leaves tend to droop.  Young leaves are yellowish.  Lateral veins on mature leaves are yellowish and clearly visible above.  The Midrib is raised below.  The Margin is mildly serrated.  The pink or red Petiole (leaf stalk) is grooved above and up to 2cm long.  Small Stipules (basal appendages of the petiole) are present.  Both the Apex and Base are tapering to rounded.

Flowers

Individual Flowers are small and occur singly or in axillary Racemes (a simple elongated inflorescence with stalked flowers that open in succession towards the apex) which are up to 7cm long and are located in leaf axils.  They are usually bisexual and actinomorphic (regular, symmetrical.  The perianth – calyx and corolla is divisible into 3 or more identical sectors or mirror images).  Bracts are small and caducous (an organ or part which is easily detached and shed early).  The Calyx has 5 Sepals that are obconical (resembles an inverted cone) and connate (joined at the base) and within which is an attached glandular disc.  The Corolla has 5 small, white or pink Petals. There are numerous – up to 20, free Stamens attached to the receptacle.  They are present in 5 whorls. Flowers are Perigynous (the petals, sepals and stamens are on the rim of the hypanthium – the cup-like receptacle).  The sessile, superior Ovary has 1 carpel (one of the foliar units of a compound pistil or ovary; a simple Pistil has 1 Carpel) and 1 locule (compartment within an organ e.g. ovary).  Two Ovules are present. The Style is long and ends in the Stigma. Flowers are insect pollinated. (Sep-Nov + Mar-Jul).

Fruit

The almost spherical Fruit is a Drupe (a fleshy, 1-seeded indehiscent fruit with the seed enclosed in a very hard stony endocarp; stone fruit e.g. peach) that is up to 1cm diameter and slightly less in length.  When mature, the drupe is purplish to black.  Drupes occur in branched bunches (Jul-Jan).  Seeds are pendulous and the Testa (seed coat) is membranous.  Seeds are small – about 5 000 per kg.  Birds disperse the seeds.

Distribution & Ecology

The major habitat for this plant is the evergreen forests near the coast as well as mountain mist-belt forest up to 2 100+m.  It also grows well on its own.  They are found in the Eastern Cape, Free State, Gauteng, Kwazulu-Natal, Limpopo, Mpumalanga, Northwest, Swaziland, Zimbabwe, Tanzania, Uganda, Malawi, DRC, Equatorial Guinea, Madagascar and Comoros.  Birds eat the Fruit.

Ethnobotany

The reddish brown and close-grained Wood does not season well and tends to split and twist.  It is used for furniture construction but does not work easily.  The smell of cut wood does not persist in timber.  Crushed plant parts smell of bitter almonds.  The harvested Bark is exported where it is used to treat prosthetic hypertrophy.  Prunus bark is much sought after for local medicinal use.  The tree can be Grown from seed and, in good conditions, grows about 1m per year.  It can become a good shade tree in a moist environment.  This is a protected tree in the RSA.  The Fruit is very bitter.

References

Boon, R. 2010. Pooley’s Trees of eastern South Africa. Flora and Fauna Publications Trust, Durban.

Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town.

Lawrence, G. H. M, 1951. Taxonomy of Vascular Plants, The Macmillan Company, New York. Tenth Printing 1965.

Palmer, E. & Pitman, N. 1972. Trees of southern Africa, Balkema, Amsterdam, Cape Town.

Schmidt, S. Lotter, M. & McCleland, W. 2002. Trees and Shrubs of Mpumalanga and the Kruger National Park.

van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town.

 

http://redlist.sanbi.org/species.php?species=3457-1

https://en.wikipedia.org/wiki/Prunus_africana

http://www.plantzafrica.com/plantnop/prunusafri.htm

http://www.plantzafrica.com/medmonographs/prunusafric.pdf

http://www.worldagroforestry.org/treedb2/AFTPDFS/Prunus_africana.PDF

http://posa.sanbi.org/flora/browse.php?src=SP

https://en.wikipedia.org/wiki/Rosaceae