The genera of Leguminosae-Caesalpinioideae & Swartzieae
Type species: S. moavi Taub.
Habit and leaf form. Rough-barked trees; without specialized short shoots; unarmed.
Phyllotaxy spiral. The leaves compound; pinnate, or pinnate to bipinnate (with Caesalpinia insolita included); paripinnate; with rachides adaxially ridged. The leaflets few per leaf (6–12); opposite or sub-opposite (3–6 pairs, eglandular); sessile to sub-sessile; without noticeably twisted petiolules; markedly asymmetrical to symmetrical or nearly so (unequal-sided at the base); pinnately veined, palmately nerved. Stipules absent or early caducous or very inconspicuous in mature leaves; membranous. Stipels absent.
Inflorescence and floral morphology. The inflorescences terminal; unbranched; simple racemes. The flowers not distichous. Bracts absent at anthesis. Bracteoles absent.
The flowers aromatic; hermaphrodite; pentamerous; coloured. Floral tube length relative to total hypanthium + calyx length 0.25. Hypanthium present; saucer-shaped to cupular. The perianth comprising distinct calyx and corolla. Calyx 5; covering the rest of the flower in bud; polysepalous; more or less regular (the sepals narrow, lanceolate, eglandular); members valvate, not imbricate. Corolla present; slightly irregular (the petals obovate, subequal); 5 (much exceeding the calyx); without greatly reduced members; polypetalous. Petals all clawed; yellow. The androecium comprising 10 members; not declinate; members all free of one another (the filaments setose-pilose towards their bases); members markedly unequal; comprising only fertile stamens. Fertile stamens 10. Anthers attached at the base of the connective; dehiscing introrsely; dehiscing longitudinally. Ovary shortly stipitate; free. Stigma not dilated (the style subulate). Ovules few (two).
Fruit, seed and seedling. Fruit a two-valved pod; straight; not noticeably winged; compressed, becoming woody. Seeds non-endospermic; with a straight or slightly oblique radicle.
Transverse section of lamina. Leaves without conspicuous phloem transfer cells in the minor veins. Druses common in the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders absent. Laminae isobilateral, with adaxial and abaxial palisades. 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 absent. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section; conspicuously pitted; thick. Stomata adaxially very rare. Abaxial: Abaxial stomata not predominantly paracytic (actinocytic and cyclocytic). 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.
Pollen ultrastructure. Tectum reticulate; finely to moderately regularly reticulate. Length of colpi greater than one half pole to pole distance (with a margocolpus). Foot layer of pollen wall with obvious projections.
Species number and distribution. 1 species (S. moavi). Tropical East Africa.
Miscellaneous. Illustrations: • S. moavi: Brenan, Fl. Tropical East Africa (1967).
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’.