Senegalia Raf.
Genus with more than 200 tropical species, of which about 70 are represented in the African continent, and of these only 4 within the study area. In this area, Senegalia species differ from Vachellia with flowers arranged in spiciform inflorescences, on peduncles without an involucre, and not in glomeruli -with a small involucre at the peduncle, towards the middle or below-, as well as lacking spiny stipules, owing its prickly character to the presence of cauline prickles.It is possible that S. ataxacantha (DC.) Kyal. & Boatwr. (Acacia ataxacantha DC.) is present in the westernmost part of the territory, especially towards the western Sahara. However, its range seems to have its northernmost limit on the 20th parallel, extending across tropical Africa from southern Mauritania and Senegal in the W, up to Sudan in the E, and up to Swaziland to the S. A lianescent shrub that can reach up to 20 m in height when climbing trees, with bipinnate leaves (with 8-20 pairs of pinnae, each with 20-40 pairs of linear leaflets) and very spiny, with prickles swollen at the base, minute -less than 8 mm- and irregularly arranged -neither paired nor in groups of 3- on stems, branches and leaf rachises. The flowers are arranged in spiciform inflorescences, cream or yellowish-white in colour, and pods are very characteristic, with a papery dark red valve.
Chevalier, A. 1928. Révision des Acacia du nord, de l’ouest et du centre africain. Revue de botanique appliquée et d’agriculture coloniale 77: 46-52; 78: 123-130; 79: 197-206; 80: 263-270; 81: 357-362; 82: 432-434; 83: 496-501; 84: 574-579; 85: 643-650; 86: 707-715.
Kyalangalilwa, B., Boatwhright, J.S., Daru, B.H. Maurin, O. & Van Der Bank, M. 2013. Phylogenetic position and revised classification of Acacia s.l. (Fabaceae: Mimosoideae) in Africa, including new combinations in Vachellia and Senegalia. Bot. J. Linn. Soc. 172: 500-523.
Miller, J.T. & Seigler, D. 2012. Evolutionary and taxonomic relationships of Acacia s.l. (Leguminosae: Mimosoideae). Austr. Syst. Bot. 25: 217-224.
Paiva, J. 1999. Acacia. In: S. Talavera & al. -eds.- Flora iberica VII(1): 11-25.
Ross, J.H. 1981. An analysis of the African Acacia species: their distribution, possible origins and relationships. Bothalia 13 (3/4): 389-413.
Key to species
1 Prickles in groups of 3, the central prickle hook-shaped and the lateral ones ± straight 2
1 Prickles geminate, black, hooked 3
2 Leaflets 0.5-1.75 mm wide, glabrous or appressed-pubescent on the underside, ciliate or not; pinnae tightly arranged —less than 5 mm apart—; petiole and leaf rachis ± densely hairy; pod(12)15-34 mm wide, ± hairy or puberulous, rarely glabrous Senegalia senegal
2 Leaflets 1.25-3.75 mm wide, glaucous, usually glabrous; pinnae spaced —over (5)7 mm apart—; petiole and leaf rachis glabrous or sparsely hairy; pod (9)11-15(18) mm wide, glabrous Senegalia asak
3 Leaves with 2-3 pairs of pinnae, each with 3-5(7) pairs of leaflets6-12 × 3-6 mm; pod (4)5-8 cm × (15)20-25(28) mm, with 8-10 seeds Senegalia laeta
3 Leaves with 1-2(4) pairs of pinnae, each with 1-2(3) pairs of leaflets(3)6-20 × 6-12 mm; pod 2.5-5.5(8) cm × 15-25 mm, with (1)2-3(4) seeds Senegalia mellifera
Updated by: J.A. Devesa.