Re-circumscription of the mimosoid genus Entada including new combinations for all species of the phylogenetically nested Elephantorrhiza (Leguminosae, Caesalpinioideae, mimosoid clade) Author O'Donnell, Shawn A. https://orcid.org/0000-0003-0731-7425 Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, NE 1 8 ST, UK shawn.odonnell@cantab.net Author Ringelberg, Jens J. https://orcid.org/0000-0003-0567-5210 Department of Systematic and Evolutionary Botany, University of Zurich, 8008 Zurich, Switzerland Author Lewis, Gwilym P. https://orcid.org/0000-0003-2599-4577 Accelerated Taxonomy Department, Royal Botanic Gardens, Kew, Richmond, TW 9 3 AE, UK text PhytoKeys 2022 2022-08-22 205 99 145 http://dx.doi.org/10.3897/phytokeys.205.76790 journal article http://dx.doi.org/10.3897/phytokeys.205.76790 1314-2003-205-99 4024A478048757B197E5CF8734331A9E Entada elephantina (Burch.) S.A. O'Donnell & G.P. Lewis comb. nov. ≡ Elephantorrhiza elephantina (Burch.) Skeels, Bull. Bur. Pl. Industr. U.S.D.A. 176: 29. 1910. Type . SOUTH AFRICA . Cape Province , Bechuland Division, Kuruman District , between Matlowing River and Kuru, W.J. Burchell 2410 ( holotype : K [K000232273]; isotypes: GH [GH00058379], P [P00418275]) . Basionym. Acacia elephantina Burch., Trav. S. Africa 2: 236. 1824. Description. Geoxylic suffrutex with erect, annual, herbaceous stems 20-90 cm arising from the woody end of an elongate subterranean axis (Fig. 12A, B ). Leaves : petiole 1.3-3.6(-8) cm long, rachis 3.5-13.5(-17.5) long; pinnae 2-4 pairs on lower leaves, 7-17 pairs on upper leaves, 3-9(-10.5) cm long, with (7-)12-45(-55) pairs of leaflets; leaflets (4-)5-10(-15) x (0.3-)0.5-2(-2.5) mm, linear to linear-oblong, apex acute to rarely obtuse, sometimes asymmetric, mucronate, base oblique, lamina glabrous (Fig. 12B, E ). Inflorescence : an axillary spiciform raceme usually confined to the lower part of the stem, (2-)4-8(-12) cm long, solitary or grouped, rachises usually glabrous (Fig. 12B-D ). Flowers : cream-coloured, yellow or yellowish-white, pedicels 1.5 mm long, articulated near the middle, with minute reddish to reddish-brown glands at the base; calyx campanulate, 1.75 mm long, distinctly toothed, glabrous; petals 2.75-3.75 mm long; stamen filaments 6.5 mm long (Fig. 12D ). Fruit : a laterally compressed, straight to slightly curved craspedium, (5-)9.5-15(-21) x 3-5.7 cm, lacking transverse septa between seeds, thus leaving the valves to separate from the replum intact upon ripening, the epicarp exfoliating from the endocarp; umbonate over seeds (Fig. 12E ). Seeds : ellipsoid, 18-26 x 13-18 x 6-13 mm. Figure 12. Entada elephantina habitat, habit, reproductive and vegetative structures. A growing in fire-prone open scrub, South Africa (photo: R Gill CC BY-NC 4.0 , Ueda (2021) observation 32241269) B geoxylic suffrutex with erect herbaceous shoots bearing finely divided bipinnate leaves and producing spiciform racemes near ground level, Eswatini (photo: L Loffler CC BY-NC 4.0 , Ueda (2021) observation 44861491) C spiciform racemes clustered near the base of the stem, South Africa (photo: tjeerd CC BY-NC 4.0 , Ueda (2021) observation 62025284) D spiciform raceme of open flowers, South Africa (photo: J Whatmore, Ueda (2021) observation 62547631) E immature fruits borne near the base of the stem, South Africa (photo: G Lewis). Distribution. Namibia, Botswana, Zimbabwe, Mozambique, South Africa, Eswatini, Lesotho. Habitat and ecology. Grassland and open scrub, sometimes gregarious (Fig. 12A ); 1060-1360 m alt. Note. Brenan (1970 , p. 28) and Ross (1974 , p. 250; 1975a , p. 141) noted that leaf characters vary considerably across the range of E. elephantina . Specimens from the western portion of the range tend to have fewer pinnae and leaflets with larger leaflets; those from eastern areas bear more numerous pinnae and leaflets, with smaller leaflets. This variation appears to be continuous, so neither author attempted to subdivide the taxon.