Senegalia erubescens
Senegalia erubescens, also known as blue thorn or yellow bark acacia, is a thorny shrub or tree in the pea family, Fabaceae. It grows in seasonally dry parts of Africa. The name Acacia erubescens is used in older floras; the combination in Senegalia dates from 2013.[1]
Description
Trees can reach ten metres tall. Their pale grey, yellowish or whitish bark sheds thin outer layers. Small hooked prickles occur in pairs below the points where leaves join the twigs. These prickles are distinct from the straight stipular thorns of many Vachellia species.[1]
The leaves divide twice, usually into three to seven pairs of branches, each carrying numerous small leaflets. White or cream flowers, sometimes tinged pink, form narrow spikes about 2–4.5 cm long. Mature pods are flattened, brown and leathery, opening to release the seeds.[1]
Range and habitat
The South African flora records a broad distribution from Tanzania and the Democratic Republic of the Congo through south-central Africa to Namibia, Botswana and northern South Africa.[2] The East African treatment records it in deciduous woodland, particularly woodland dominated by Brachystegia, at approximately 850–1,680 metres. That elevation range applies to the regional flora records.[1]
Woodland ecology
A survey of Botswana's Kgatleng District between 2013 and 2016 examined 77 plots and identified five woody vegetation communities. A community characterised by S. erubescens and Senegalia mellifera was the most widespread in the resulting district map. The two plants were indicator species used to recognise the community, rather than its only components.[3]
The authors discussed woody encroachment as a concern for local grazing land. They did not find statistically significant differences in species richness among their five communities. The study therefore supports a regional account of vegetation composition, rather than a claim that this tree invariably reduces biodiversity.[3]
References
- ↑ 1.0 1.1 1.2 1.3 Royal Botanic Gardens, Kew. “Senegalia erubescens”, including Brenan (1970), Flora Zambesiaca, and Gillett, Polhill and Verdcourt (1971), Flora of Tropical East Africa. Accessed 9 October 2026.
- ↑ World Flora Online. “Senegalia erubescens”, including the South African National Biodiversity Institute e-Flora treatment. Accessed 9 October 2026.
- ↑ 3.0 3.1 Tshireletso, K., and colleagues (2018). “Diversity patterns of woody vegetation of Kgatleng District, Botswana”. Biodiversity & Ecology 6: 416–423. doi:10.7809/b-e.00353. Accessed 9 October 2026.