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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Stahlia Bello

Caesalpinia monosperma Tul.

Type species: S. monosperma (Tul.) Urb. (S. maritima Bello).

Habit and leaf form. Trees; without specialized ‘short shoots’; unarmed.

Phyllotaxy spiral. The leaves compound; pinnate; paripinnate. The leaflets few per leaf (4–6 jugate, with prominent black glands scattered beneath); petiolulate; without noticeably twisted petiolules; markedly asymmetrical to symmetrical or nearly so; ovate-lanceolate, with a predominant ‘midrib’ (this sometimes displaced). Stipules absent or early caducous or very inconspicuous in mature leaves. Stipels absent.

Inflorescence and floral morphology. The inflorescences axillary and terminal; unbranched; simple racemes. The flowers not distichous. Bracts connate and valvate, caducous, absent at anthesis. Bracteoles absent; absent at anthesis.

The flowers medium-sized, nearly regular; hermaphrodite; pentamerous; coloured. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present. The perianth comprising distinct calyx and corolla. Calyx covering the rest of the flower in bud; not Swartzieae type; polysepalous; members imbricate. Corolla present; only slightly irregular; abaxially covered with subclavate papillae, 5; without greatly reduced members; polypetalous. Petals subequal, imbricate; imbricate-ascending; yellow, or red. The androecium comprising 10 members; members all free of one another (the filaments woolly, connivent above); comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective. Ovary sessile or subsessile; free. Stigma not dilated (the filiform style apically truncate). Ovules few.

Fruit, seed and seedling. Fruit (1(-2) seeded, indehiscent; straight; plano-convex, oval or oval-orbicular, not becoming woody. The mature valves smooth, without prominent venation. Seeds non-endospermic; compressed,; with a straight or slightly oblique radicle; amyloid-negative. Cotyledons not flat.

Transverse section of lamina. Leaves without conspicuous phloem transfer cells in the minor veins. Druses absent from the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders common (the veins transcurrent), or 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 not seen. No compound or branched eglandular hairs seen. Capitate glands not seen. Expanded and embedded hair-feet 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 not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating; conspicuously pitted in optical section; scarcely staining with safranin; medium-thin.

Wood anatomy. Wood storied.

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 smooth.

Species number and distribution. 1 species (S. monosperma). Puerto Rico.

Tribe. Caesalpinieae.

Miscellaneous. Illustrations: • S. monosperma: Addisonia 12 (1927). • S. monosperma, 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.’.