Oberholzeria FABACEAE

Abstract

A diagnostic description of the genus is given. The geographical distribution is outlined, together with a selection of important literature, and an explanation of the etymology of the name. This is followed by a short summary of its position in the phylogeny of the family and of the past and present classification in a phylogenetic context.

This is followed by a synoptical treatment of the single species (succulent) of the genus, complete with typification details, geographical and ecological data, a diagnostic description, and, where applicable, notes on phylogenetic placement and relationships, as well as economic and/or horticultural importance.

Oberholzeria Swanepoel & al. (PLoS One 10(3: e0122080): 11–12, 2015). Type: Oberholzeria etendekaensis Swanepoel & al. – Papilionoideae – unplaced – Distr: NW Namibia. Etym: For Johanna (“Hannelie”) Allettha Oberholzer (*1965), wife of the Namibian botanist Wessel Swanepoel who described the taxon.

Erect, single-stemmed, biennial or short-lived perennial succulent shrublets to 1 m tall and 1.2 m ⌀, glabrous; presence of nitrogen-fixing bacterial nodules on the R unknown; stem and Br fleshy with woody remains, lower branches deciduous, leaving prominent crescent-shaped scars; L spirally arranged, petiole and petiolules fleshy, lamina pinnately 3-foliolate, leaflets often patent and erect, ovate, rarely suborbicular, fleshy, glabrous, green or glaucous with a white bloom, 1–2.5 × 0.9–2.2 cm, margin entire; stipules paired, linear-lanceolate or linear-triangular, 2–2.4 mm long, fleshy; Inf leaf-opposed, or terminal on young branches and branchlets, racemose, 35- to 65-flowered, axis 25–50 mm; peduncle 9–17 mm; Fl zygomorphic, subtended by a lanceolate fleshy caducous Bra 2.5–3 × 0.7–0.9 mm, bracteoles absent; Ped 10–12 mm; Cal dorsiventrally flattened, with 5 triangular lobes that are longer than the tube; Pet white with yellow-green venation and paired large dark brown spots towards the basal margins, standard Pet narrowly obovate, retuse, 6.2–7.5 × 2.9–3.2 mm, reflexed, lamina folded medially towards the apex, basal part fleshy, claw broad, indistinct and cucullate, wings broadly falcate, lamina 7.1–7.5 × 3.1–3.5 mm, longer than the keel, auriculate at the base with 5 columns of 3–12 crescent-shaped minute intercostal pockets, claw short but distinct, ± 0.6 mm long, keel rostrate, lamina 5.7–5.9 × 2.6 mm, apex yellow to brown, claw short but distinct, 0.7–1 mm long; St monadelphous, fused into a sheath that is closed above; Anth dimorphic, 5 long and basifixed, narrowly ovate, alternating with 5 short and dorsifixed; Ov glabrous; Fr obovate-clavate, ± 2.3 × 1.4 × 0.6 cm, laterally flattened, 1-seeded, green, khaki-coloured when dry, valves thin and papery, indehiscent; Se asymmetrically obovate, laterally compressed, faintly verrucose, khaki-coloured or khaki-green, hilum not fleshy, cream-coloured.

This recently described monotypic genus has been found to be sister to tribe Genisteae or to the combined clade of tribes Genisteae + Crotalarieae in a molecular analysis. The succulent habit is unique within these clades. Oberholzeria is regarded as a taxonomically isolated relictual species.

O. etendekaensis Swanepoel & al. (PLoS One 10(3: e0122080): 12, figs. 5 and 6 (pp. 8–9), 2015). Type: Namibia, Kunene Region (Swanepoel 316 [WIND, PRE]). − Distr: NW Namibia (Kunene: Kaokoveld: Great Escarpment of the Etendeka Mts.); S-facing ravines on stony soil and screes, 850–950 m; known from a single population only. − Figs. 1 and 2.

Fig. 1

Oberholzeria etendekaensis (locus classicus). (Copyright: W. Swanepoel)

Fig. 2

Oberholzeria etendekaensis (same data for Fig. 1). (Copyright: W. Swanepoel)

Description as for the genus.