Gabonius Wieringa & Mackinder, 2013

Wieringa, Jan J., Mackinder, Barbara A. & Van Proosdij, André S. J., 2013, Gabonius gen. nov. (Leguminosae, Caesalpinioideae, Detarieae), a distant cousin of Hymenostegia endemic to Gabon, Phytotaxa 142 (1), pp. 15-24 : 17

Gabonius Wieringa & Mackinder gen. nov.

Type: Hymenostegia ngouniensis , for type specimen details see below.

Shrub or tree, usually small but may attain 35 m tall. Stipules in pairs, free but touching at the base, caducous. Bud scales absent. Leaves paripinnate, leaflets in (2–)5–7 pairs, subsessile, narrowly elliptic to elliptic, ovate to sub-rhombate, adaxial surface glabrous, abaxial surface glabrous or with sparse indumentum, crater-like glands present, visible at × 10 or higher magnification. Inflorescence a terminal or axillary raceme, axes puberulous, bracts caducous, bracteoles persistent, opposite, petaloid, conspicuous, adaxial surfaces touching along margins prior to anthesis. Petals 5, adaxial and lateral petals large, yellow and white, similar in size, abaxial petals smaller, white. Stamens 10. Ovary stipitate, the stipe fused along most of its length to the adaxial sidewall of the hypanthium, densely hairy along the margins, stigma peltate. Pod compressed, glabrous, trapeziform, broadest at about one-third distance from the apex, dehiscent. Seeds 1–2, discoid.

Etymology: —This new, so far monotypic genus is named after Gabon, a country where it is not only endemic to, but in which it also occurs over a large extent; the known distribution seems to fit that country very well, and a species distribution model of the species (see below) predicts it is more or less confined to this country as well. Although Gabon has a large number of endemics, c. 500 species are recorded as endemic and another 100 as near endemic ( Sosef et al. 2006), only a few of these species have such a large distribution within the country. Gabonius has the male gender.

Note: —The only slightly similar name that exists is Gabunia Stapf (1902: 136) , but that name differs in several letters and is a synonym of Tabernaemontana Linné (1753: 210–211) (Apocynaceae) with no current use, so we do not foresee any possibilities for confusion between these two.