| # The genera of Leguminosae-Caesalpinioideae and Swartzieae |

L. Watson and M.J. Dallwitz

### Caesalpinia L.

Balsamocarpon Clos in Gay (C. brevifolia), Guilandina L., Denisophytum Vig., Pomaria Cav. Cf. also Guilandia P. Br.; Bonduc, Campecia and Ticanto Adans,; Pseudosantalum Mill.; Poincia Neck.; Tara Molina; Coulteria H.B. & K.; Adenocalyx Bert.; Libidibia Schlechtd.; Cladotrichium Vog.; Erythrostemon Klotsch.; Lebidibia Griseb.; Cinclidocrpus Zoll. Also Guaymasia, Moparia, Nicarago, Poicianella, Russellodendron and Biancaea of Britton and Rose (1930).

Type species: C. brasiliensis L.

Habit and leaf form. Trees, or shrubs, or herbs, or climbers or scramblers; without tendrils; leaves and inflorescences crowded on ‘short shoots’, or without specialized ‘short shoots’; armed (with prickly branchlets and rachides), or unarmed.

Phyllotaxy spiral. The leaves compound; bipinnate (ending in a single pinna, or a pair of them), or pinnate (rarely, only in Chile and Cuba, = Balsamocarpon); when bipinnate, with opposite or sub-opposite pinnae; when bipinnate, with opposite or sub-opposite leaflets, or with alternate leaflets; when pinnate, i.e. usually, paripinnate; with rachides adaxially ridged. The leaflets many per leaf, or few per leaf; opposite or sub-opposite to alternate; petiolulate to sessile to sub-sessile; with markedly twisted petiolules, or without noticeably twisted petiolules; symmetrical or nearly so (usually), or markedly asymmetrical (sometimes, at the base); pinnately veined, with a predominant ‘midrib’. Stipules absent or early caducous or very inconspicuous in mature leaves, or present, persistent and conspicuous in mature leaves; leafy, or spinescent, or membranous. Stipels present, or absent.

Inflorescence and floral morphology. The inflorescences axillary, or terminal; branched; of racemose units; panicles (of racemes). The flowers not distichous. Bracts absent at anthesis, or persistent beyond anthesis. Bracteoles absent; absent at anthesis.

The flowers small, or large, or showy; hermaphrodite, or hermaphrodite and unisexual (dioecious in subgen. Guilandina, andromonoecious in C. pulcherrima); pentamerous; coloured. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present; saucer-shaped to cupular. The perianth comprising distinct calyx and corolla. Calyx 5 (with the lowest tooth outside); covering the rest of the flower in bud, or not covering the rest of the flower in bud; not Swartzieae type; polysepalous (the sepals free to the hypanthium rim); more or less regular to markedly irregular (the abaxial member often larger); members imbricate (with the abaxial member outside). Corolla present; slightly irregular to very irregular (the petals slightly unequal, or the adaxial one markedly smaller); 5; without greatly reduced members; polypetalous. Petals round or oblong, clawed, or clawed and sessile; very imbricate; imbricate-ascending; yellow, or red. Disk absent. The androecium comprising 10 members; members all free of one another; members all more or less equal in length (but usually declinate); comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective; dehiscing introrsely; dehiscing longitudinally. Ovary sessile or subsessile; free. Stigma truncate, concave or minute, not dilated (the style filiform, rarely apically clavate). Ovules few, or numerous, or solitary.

Fruit, seed and seedling. Fruit a two-valved pod, or indehiscent (sometimes spiny); straight, or curved; not internally septate (but often filled between the seeds); without markedly twisting or enrolling valves; winged longitudinally, or not noticeably winged; sometimes 1 winged (along only one suture); not becoming woody. Seeds endospermic, or non-endospermic; with a straight or slightly oblique radicle; amyloid-negative; with galactomannan. Cotyledons flat; of Type 2, or Type 3, or Type 4; with a vascular system in one plane; epigeal, or hypogeal.

Transverse section of lamina. Leaves without conspicuous phloem transfer cells in the minor veins. Druses common in the mesophyll. Mesophyll secretory cavities (gland-dots) common, or absent; without a lining of epithelium. Adaxial hypodermis absent. Leaf girders absent. Laminae dorsiventral. Mesophyll without unaligned fibres or sclereids. Minor veins lacking accompanying fibrous tissue.

Leaf lamina epidermes. Epidermal crystals not seen either adaxially or abaxially. Simple unbranched hairs common, or not seen; scabrid, or smooth. No compound or branched eglandular hairs seen. Capitate glands present, or 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, or markedly sinuous in high-focus optical section; conspicuously pitted, or not conspicuously pitted. Stomata adaxially common and widespread, or adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic, or not predominantly paracytic. Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating; conspicuously pitted in optical section, or not conspicuously pitted in optical section; scarcely staining with safranin; medium-thin.

Wood anatomy. Wood without septate fibres; storied, or not storied; without normal intercellular canals; without traumatic canals. Intervascular pits very small, or medium to large.

Pollen ultrastructure. Tectum punctate (rarely), or reticulate; smooth punctate, or puncticulate; strongly irregularly coarse-reticulate. Length of colpi greater than one half pole to pole distance (with a margocolpus). Foot layer of pollen wall with obvious projections.

Cytology. Basic chromosome number, x = 12. 2n = 22 (?), or 24.

Species number and distribution. About 100 species. Tropical and subtropical.

Tribe. Caesalpinieae.

Comments. Widely cultivated.

Miscellaneous. Illustrations: • Caesalpinia bonduc (as bonducella): Fl. Brasiliensis 15 (1870). • Caesalpinia echinata: Fl. Brasiliensis 15 (1870). • Caesalpinia ferrea and C. rubicunda: Fl. Brasiliensis 15 (1870). • Caesalpinia welwitschiana: Aubréville, Flore du Gabon (1968). • Caesallpinia sappan: Baillon, Histoire des Plantes 2 (1870). • Caesalpinia pulcherrima: Maund & Henslow (1839). • Caesalpinia vernalis: Bot. Mag. 133 (1907). • Caesalpinia echinata: Nat. Pflanzenfam. III (1894). • Caesalpinia trothae subsp. erlangeri: Engler & Drude, Pflanzenwelt Afrikas 9 (1915). • Caesalpinia oligophylla: Engler & Drude, Pflanzenwelt Afrikas 9 (1915). • C. cf. crista: Schery, Ann. Miss. Bot. Gard. 38 (1951). • Caesalpinia mexicana, 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: 4th August 2019. delta-intkey.com’.

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