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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Dicymbe Spruce ex Benth.

Dicymbopsis Ducke

Type species: D. corymbosa Spruce ex Benth.

Habit and leaf form. Trees, or shrubs (rarely); unarmed.

Phyllotaxy spiral. The leaves compound; pinnate; paripinnate. The leaflets few per leaf; opposite or sub-opposite; petiolulate; without noticeably twisted petiolules; symmetrical or nearly so; pinnately veined, with a predominant ‘midrib’. Stipules absent or early caducous or very inconspicuous in mature leaves; membranous. Stipels absent.

Inflorescence and floral morphology. The inflorescences branched; of racemose units (racemose or corymbose); panicles. The flowers not distichous. Bracts thick and shell-like, but caducous and absent at anthesis. Bracteoles present (thick and leathery); relatively large and enclosing the flower buds; persistent beyond anthesis; valvate.

The flowers rather large; hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx; white or green. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present; cupular (short and thick). Calyx 4 (the sepals often apically bifid); not Swartzieae type; polysepalous; more or less regular, or markedly irregular; members imbricate. Corolla present; slightly irregular; 5; without greatly reduced members; polypetalous. Petals imbricate; imbricate-ascending; white. The androecium comprising 10 members; members all free of one another; 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; free, or eccentric, with the stipe adnate. Stigma dilated (the style involute in bud). Ovules numerous.

Fruit, seed and seedling. Fruit a two-valved pod; winged longitudinally, or not noticeably winged; interpretable as 2 winged (being 2-ribbed along the adaxial suture). The mature valves with conspicuous, prominent, raised venation; conspicuous venation oblique, not predominantly longitudinal. Seeds with a straight or slightly oblique radicle; amyloid-positive.

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 present; prisms. Simple unbranched hairs common. 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. Adaxial: Adaxial interveinal epidermal cell walls markedly sinuous in high-focus optical section; conspicuously pitted; 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; thick.

Wood anatomy. Wood not storied.

Pollen ultrastructure. Tectum reticulate, or striate; rugulose reticulate; interwoven striate. Length of colpi greater than one half pole to pole distance, or less than one half pole to pole distance.

Species number and distribution. About 20 species. Tropical South America.

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

Miscellaneous. Illustrations: • D. corymbosa: Fl. Brasiliensis 15 (1870). • D. altsonii, e.m. scanned pollen (Graham & Barker, 1981). • D. bernardii and D. jenmanii, e.m. scanned pollen (Graham & Barker, 1981).

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.’.