The genera of Leguminosae-Caesalpinioideae & Swartzieae
Type species: D. senegalense J.F. Gmel.
Habit and leaf form. Trees; unarmed.
Phyllotaxy distichous, or spiral. The leaves compound; pinnate; paripinnate. The leaflets few per leaf; alternate; petiolulate; without noticeably twisted petiolules; symmetrical or nearly so; with a strong, continuous marginal nerve. Stipules absent or early caducous or very inconspicuous in mature leaves; membranous. Stipels absent.
Inflorescence and floral morphology. The inflorescences axillary (or lateral on year-old wood); branched; of racemose units; panicles. The flowers distichous. Bracts absent at anthesis. Bracteoles present; small, not enclosing the flower buds; absent at anthesis; not valvate; free.
The flowers small; hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx and in the corolla; white or green. Hypanthium absent, the androecium hypogynous. The perianth exclusively sepaline. Calyx 4; covering the rest of the flower in bud; polysepalous; more or less regular; members somewhat imbricate (but subvalvate). Corolla absent. Disk absent. The androecium comprising 10 members; members all free of one another; members markedly unequal; comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective. Ovary sessile or subsessile; free. Stigma small, but dilated. Ovules few.
Fruit, seed and seedling. Fruit sessile, orbicular, 1-seeded indehiscent (with fibrous exocarp and bony endocarp); drupaceous; not becoming woody. The mature valves without prominent venation. Seeds non-endospermic; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons epigeal.
Transverse section of lamina. Leaves with conspicuous phloem transfer cells in the minor veins. Druses absent from the mesophyll. Mesophyll secretory cavities (gland-dots) common; epithelium-lined. Adaxial hypodermis absent. Leaf girders common (the veins transcurrent). 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; smooth. 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; all medium to thick-walled; hair feet all simple, without vertical walls. Basally bent hairs absent. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section; conspicuously pitted; thin. 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; staining normally with safranin; thick.
Wood anatomy. Wood not storied; with normal intercellular canals; without traumatic canals.
Pollen ultrastructure. Tectum punctate; rugulose punctate. Length of colpi greater than one half pole to pole distance.
Cytology. Basic chromosome number, x = 11. 2n = 22.
Species number and distribution. 4 species (D. beurmannianum, D. macrocarpum, D. microcarpum, D. senegalense). Tropical Africa.
Tribe. Detarieae; Detarieae sensu stricto clade of Bruneau et al. (2008).
Miscellaneous. Illustrations: • D. senegalense: Baillon, Histoire des Plantes 2 (1870). • D. senegalense: Engler & Drude, Pflanzenwelt Afrikas 9 (1915). • D. macrocarpum: Engler, Pflanzenwelt Afrikas (1910). • D. macrocarpum and D. microcarpum: 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. delta-intkey.com/caes’.