Senegalia burkei (Benth.) Kyal. & Boatwr. ( = Acacia burkei Benth.)
Common names: black monkey-thorn (Eng.); swartapiesdoring (Afr.); umkhaya wehlalahlathi, umbabampala (isiZulu); umkhaya (siSwati); mokgwa, mokoba (Setswana); mokwaripa, mongangatau (Sesotho sa Leboa); munanga (Tshivenda)
SA Tree No: 161
Senegalia burkei is a distinctive deciduous tree that can be identified easily throughout the year. It has spikes of creamy white flowers in early summer, followed by bright red seed pods. Small- and large-leaflet forms are found in different regions.
A large, spreading, deciduous tree, from 12 m up to 25 m tall, with a rounded, flattened or open crown. Bark on the young branches is greyish yellow to reddish brown and velvety, but also pale or dark greyish yellow to dark brown, irregularly fissured and flaking on the older branches and stems. The branches often have dark, hooked thorns on knobs. Young branchlets are covered with fine brown hairs that turn grey with age. Thorns are short, dark, sharply hooked and strongly recurved. They grow in pairs, far apart below the leaf buds, and are 3–9 mm long.
Senegalia burkei has twice compound leaves that are alternate and the leaf stalk is often covered in fine white hairs. The dark green compound leaf may have 3–10, opposite or subopposite, feather pairs that vary in shape and size, with fewer pairs in drier areas and more in wetter areas. The leaves are short, stiff and stand upright with a gland at the junction of the top pinnae pairs. A leaf is 25–70 mm long, and a leaflet is 12–25 mm long.
Inflorescence is a 15–85 mm long spike. Flowers are scented, yellowish white, sessile, with a distinct pinkish to pinkish red calyx. White flower spikes in small groups appear in late spring or summer (October to January) and fruiting is from December to May. Pods are in drooping clusters. The flat bean-like pods have a pointed tip and turn red-brown to dark brown as they ripen. They are remarkably veined, particularly when young. Ripe pods turn black, thinly textured, up to 170 × 24 mm, and split open on the tree.
Least Concern (LC). This species has not been fully assessed but is not considered to be of conservation concern.
Distribution and habitat
Senegalia burkei is found in southeastern Botswana and southeastern Zimbabwe, Mozambique and Swaziland, and in Gauteng, Limpopo, Mpumalanga and KwaZulu-Natal in South Africa. It occurs on a variety of soil types and on rocky slopes in the dry river valley scrub, thornveld or in mixed woodland.
Derivation of name and historical aspects
This species used to be known as Acacia burkei. The name Acacia is derived from the Greek word akakia, the name for the Egyptian thorn, probably derived from the word ake meaning ‘a point’. The genus Acacia has been retypified and split, with the result that all the African acacias now fall into the recently defined genera: Vachellia or Senegalia. The genus Senegalia means ‘referring to Senegal’ in Africa. The name was first published by Rafinesque in 1838, but it is not clear why the name was chosen. The species name burkei, refers to the naturalist and collector, Joseph Burke (1812–1873), who catalogued this tree in the 1840s, and collected specimens of it near Magaliesberg.
The most important pollinators of African acacias are social and solitary bees, although other insects and nectar-feeding birds are important in specific cases. Senegalia burkei is one of the species that secretes nectar, and its flowers attracts many visitors, although many of these are probably not important as pollinators.
The gum is eaten by people, monkeys and bushbabies. Bark and roots are used in traditional medicine to treat eye and back complaints. The roots are also used to make a yellow dye. The leaves were believed to attract lightning.
The wood has thin yellowish sapwood and a golden- to dark brown, strong, hard and heavy heartwood (air-dry 910kg/m3). The wood is used to make furniture, tool handles and to make long-lasting fence posts, as it is termite-resistant. The heartwood makes a good quality fuel with coals that burn for a long time.
The leaves are eaten by black rhino, giraffe, kudu, nyala and impala. Dry pods have a high nutritional value and are eagerly eaten by cattle and game.
The tree can be used to provide shade, and it makes a good bonsai subject. Its root system can become aggressive, therefore, it should not be planted close to paving or buildings.
Growing Senegalia burkei
Collect fresh seeds from the trees and soak well in hot water overnight. Avoid picking up seeds from the ground as insects may infest them. Sow the swollen seeds in river sand, using flat seedling trays. Germination takes place in 3 to 4 weeks. Transplant when they reach two-leaf stage into a nursery black bag or pot and take care not to damage the taproot. Use a good general well-drained potting mix. Senegalia burkei has a slow growth rate and can withstand low temperatures, but not cold wind.
- California Plant Names: Latin and Greek meanings and derivations, A Dictionary of botanical and biographical etymology compiled by Michael L. Charters: http://www.calflora.net/botanicalnames/pageSA-SH.html, accessed 29 February 2016.
- Experiment.com. Tree profile: Black monkey thorn. Posted by Keala Cummings Apr 15, 2014. https://experiment.com/u/Lv3EQ, accessed 29 October 2015.
- iSpot southern Africa http://www.ispotnature.org/species-dictionaries/sanbi/Senegalia%20burkei?nav=search
- Leafco. Senegalia (= Acacia) burkei page http://www.leafco.co.za/shop/products/black-monkey-thorn?back=/shop/by-category/trees?page=9, accessed 29 October 2015.
- Boon, R. 2010. Pooley's trees of eastern South Africa, a complete guide. Flora & Fauna Publications Trust, Durban.
- Foden, W. & Potter, L. 2005. Senegalia burkei (Benth.) Kyal. & Boatwr. National Assessment: Red List of South African plants version 2015.1. Accessed on 2016/02/29.
- Grant, R. & Thomas ,V. 2000. Sappi tree spotting: bushveld. Jacana, Johannesburg.
- Jackson, W.P.U. 1990. Origins and meanings of names of South African plant genera. University of Cape Town.
- Venter, F. & Venter, J.A. 2012. Making the most of indigenous trees. Briza Publications, Pretoria.
Thobile Mlaba (WIL student) & Sthembile Zondi (Chief Horticulturist)
KwaZulu-Natal National Botanical Garden
Plant Type: Tree
SA Distribution: Gauteng, Limpopo, Mpumalanga, North West
Soil type: Sandy, Loam
Flowering season: Spring, Early Summer
Flower colour: White, Pink, Cream
Aspect: Full Sun
Gardening skill: Average