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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Neochevalierodendron J. Léon.

Hymenostegia stephanii

Type species: N. stephanii (A. Chev.) J. Léonard.

Habit and leaf form. Trees; unarmed.

The leaves compound; pinnate, or bifoliolate; paripinnate. The leaflets few per leaf (usually four, rarely only two); opposite or sub-opposite and alternate (the lower pair alternate, the upper opposite); petiolulate; with markedly twisted petiolules; markedly asymmetrical (obliquely ovate); with a strong, continuous marginal nerve (at the bases of the first pair), or without a continuous marginal nerve. Stipules present, persistent and conspicuous in mature leaves to absent or early caducous or very inconspicuous in mature leaves; connate (more or less united). Stipels absent.

Inflorescence and floral morphology. The inflorescences axillary and terminal; unbranched; with compressed pedicels, simple racemes (these shorter than the leaves). The flowers not distichous. Bracts caducous, absent at anthesis. Bracteoles present; broadly ovate-rounded, 1-nerved, more or less petaloid, small, not enclosing the flower buds; absent at anthesis (caducous); not valvate; free.

The flowers hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx. Hypanthium present; tubular. The perianth comprising distinct calyx and corolla. Calyx 4; covering the rest of the flower in bud; leathery, polysepalous; more or less regular; members very imbricate. Corolla present; very irregular (the similar adaxial and lateral petals large, suborbicular, cordate and tomentose within, the abaxial two minute); 5; including greatly reduced members (the two abaxial members); polypetalous. Petals clawed (the three large ones), or sessile; white. Disk absent. The androecium comprising 10 members; with united members (all ten filaments basally connate); members all more or less equal in length; comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective; dehiscing longitudinally. Ovary stipitate; eccentric, with the stipe adnate (the stipe totslly adnate to the hypanthium). Ovules few (2–4).

Fruit, seed and seedling. Fruit a two-valved pod; winged longitudinally, or not noticeably winged; very large and stipitate, not becoming woody. The mature valves with conspicuous, prominent, raised venation; conspicuous venation transverse, not predominantly longitudinal. Seeds with a straight or slightly oblique radicle.

Species number and distribution. 1 species (N. stephanii). Equatorial West Africa.

Tribe. Detarieae; Amherstieae clade of Bruneau et al. (2008).

Miscellaneous. Illustrations: • N. stephanii: Aubréville, Flore du Gabon (1968).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classification. See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1993 onwards. The genera of Leguminosae-Caesalpinioideae and Swartzieae: descriptions, illustrations, identification, and information retrieval. In English and French. Version: 22nd March 2017.’.