Entada elephantina (Burch.) S.A. O'Donnell & G.P. Lewis, 2022

O'Donnell, Shawn A., Ringelberg, Jens J. & Lewis, Gwilym P., 2022, Re-circumscription of the mimosoid genus Entada including new combinations for all species of the phylogenetically nested Elephantorrhiza (Leguminosae, Caesalpinioideae, mimosoid clade), PhytoKeys 205, pp. 99-145 : 99

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) × (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) × 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 × 13-18 × 6-13 mm.

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.

Figures

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).