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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Gilbertiodendron J. Léon.

Type species: G. demonstrans(Baill.) J. Léonard.

Habit and leaf form. Trees; unarmed.

Phyllotaxy spiral. The leaves compound; pinnate, or bifoliolate (rarely); imparipinnate (rarely), or paripinnate (mostly). The leaflets with marginal glands, few per leaf; opposite or sub-opposite, or alternate (rarely); petiolulate, or sessile to sub-sessile; without noticeably twisted petiolules; symmetrical or nearly so; pinnately nerved, with a predominant ‘midrib’; without a continuous marginal nerve. Stipules present, persistent and conspicuous in mature leaves; leafy (often with a basal, reniform appendage). Stipels absent.

Inflorescence and floral morphology. The inflorescences axillary, or terminal (or on old wood); unbranched and branched; of racemose units; simple racemes, or panicles. The flowers not distichous. Bracts usually small. Bracteoles present (sepaloid); relatively large and enclosing the flower buds; persistent beyond anthesis; valvate.

The flowers hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx and in the androecium. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present; asymmetrically saucer-shaped to cupular. Calyx 4 (the median lobe 2-toothed or bifid); polysepalous; more or less regular, or markedly irregular; members imbricate. Corolla present; very irregular (the middle petal large or very large, fan-like and 2-lobed, the rest equal, small or scale-like); 5; including greatly reduced members, or without greatly reduced members; polypetalous. Petals clawed (the large one), or sessile; imbricate. The androecium comprising 3–9 members; with united members, or members all free of one another (rarely); members all more or less equal in length (rarely), or markedly unequal (usually); including staminodia (usually), or comprising only fertile stamens (rarely). The staminodia when present, 1–6; more or less reduced. Fertile stamens 3 (usually), or 4, or 5, or 9. Anthers attached well above the base of the connective; dehiscing longitudinally. Ovary stipitate; eccentric, with the stipe adnate. Stigma not dilated. Ovules few, or numerous.

Fruit, seed and seedling. Fruit a two-valved pod; valves twisting and enrolling during dehiscence; becoming woody. The mature valves with conspicuous, prominent, raised venation; conspicuous venation predominantly longitudinal. Seeds not arillate; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons not flat; epigeal.

Transverse section of lamina. Leaves with conspicuous phloem transfer cells in the minor veins. 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 present; (at least some of them) thin-walled; hair feet all simple, without vertical walls. Basally bent hairs present. Adaxial: Adaxial interveinal epidermal cell walls markedly sinuous in high-focus optical section; conspicuously pitted, or not conspicuously pitted. Stomata adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic. Abaxial epidermis papillate interveinally; with papillae over-arching the stomata. Abaxial interveinal epidermal cell walls markedly sinuous in high-focus optical section; conspicuously pitted in optical section, or not conspicuously pitted in optical section; staining normally with safranin.

Cytology. Basic chromosome number, x = 12. 2n = 24.

Species number and distribution. About 27 species (including many formerly referred to Macrolobium). West tropical Africa.

Tribe. Detarieae (Amherstieae of Cowan and Polhill 1981); Amherstieae clade of Bruneau et al. (2008).

Miscellaneous. Illustrations: • G. demonstrans (as Vouapa), with Anthonotha macrophylla and Berlinia spp.: Baillon, Adansonia VI (1865). • G. ogoouense: Léonard, in Fl. du Congo Belge (1952). • G. dewevrei and G. ogoouense: Aubréville, Flore du Gabon (1968). • G. dewevrei leaflet: detail of abaxial epidermis.

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.’.