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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Talbotiella Bak.f.

~ Hymenostegia.

Type species: T. eketensis Bak.f.

Habit and leaf form. Trees (mostly), or shrubs (T. eketensis); unarmed.

The leaves compound; pinnate; paripinnate. The leaflets many per leaf, or few per leaf (2–26 pairs); opposite or sub-opposite; sessile to sub-sessile; markedly asymmetrical; pinnately veined, with a predominant ‘midrib’; without a continuous marginal nerve. Stipules absent or early caducous or very inconspicuous in mature leaves (caducous); membranous; not connate (free, basally auriculate or palmate). Stipels absent.

Inflorescence and floral morphology. The inflorescences axillary; unbranched; simple racemes (these several to many flowered, lax). The flowers not distichous. Bracts absent at anthesis, or persistent beyond anthesis. Bracteoles near the pedicel apices, present (linear-oblong, petaloid and showy); small, not enclosing the flower buds; persistent beyond anthesis; not valvate; free (not involucrate).

The flowers small; hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx and in the corolla, or in the calyx, in the corolla, and in the androecium. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present; short (up to 3 mm deep); narrowly campanulate. The perianth exclusively sepaline. Calyx 4 (the sepals sub-orbicular); covering the rest of the flower in bud; polysepalous; more or less regular; members imbricate. Corolla absent. Disk absent. The androecium comprising 8–12 members; members all free of one another; members all more or less equal in length; comprising only fertile stamens. Fertile stamens (8–)10(–12). Anthers attached well above the base of the connective; dehiscing longitudinally. Ovary stipitate (the stipe up to 2 mm long); eccentric, with the stipe adnate (the latter hairy and fused to the inner adaxial wall of the hypanthium). Stigma small, dilated (capitellate), or not dilated. Ovules few (2–3).

Fruit, seed and seedling. Fruit a two-valved pod (glabrous or pubescent, laterally compressed, slightly beaked, with triangular valves broader distally); not internally septate; valves twisting and enrolling during dehiscence, or without markedly twisting or enrolling valves (?); becoming woody. The mature valves without prominent venation. Seeds not arillate; with a straight or slightly oblique radicle. Cotyledons flat, or not flat; of Type 4; with a vascular system ramified throughout; epigeal.

Transverse section of lamina. Druses absent from the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders absent. Laminae dorsiventral. Mesophyll without unaligned fibres or sclereids. Minor veins mainly with abundant accompanying fibres.

Leaf lamina epidermes. Epidermal crystals not seen either adaxially or abaxially. Simple unbranched hairs common; scabrid. No compound or branched eglandular hairs seen. Capitate glands not seen. Hooked hairs not seen. Cassieae-type leaf pseudo-glands not seen. Expanded and embedded hair-feet absent. Basally bent hairs present. Adaxial: Adaxial interveinal epidermal cell walls markedly sinuous in high-focus optical section; conspicuously pitted; medium-thick. Stomata adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic. Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls markedly sinuous in high-focus optical section; conspicuously pitted in optical section; staining normally with safranin; of medium thickness.

Species number and distribution. About 8 species (T. batesii, T. breteleri (formerly Hymenostegia sensu stricto), T. eketensis, T. gentii, T. korupensis, T. velutina). Tropical West Africa.

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

Miscellaneous. Illustrations: • T. atesii and T. eketensis: Aubréville, Flore du Cameroun (1970). • T. bakossiensis: Mackinder et al. (2010). • T. ebo: Mackinder et al. (2010). • T. korupensis: Mackinder et al. (2010). • T. velutina: Mackinder et al. (2010).

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.’.