| # The genera of Leguminosae-Caesalpinioideae and Swartzieae |

L. Watson and M.J. Dallwitz

### Haematoxylum L.

Cymbosepalum Baker, Haematoxylon

Type species: H. campechianum L.

Habit and leaf form. Trees, or shrubs (with coloured wood); leaves and inflorescences crowded on ‘short shoots’; armed (often, with spiny branchlets), or unarmed.

Phyllotaxy spiral. The leaves compound; pinnate, or bipinnate (by dividing of the lower pinnae); mostly paripinnate; with rachides adaxially ridged. The leaflets many per leaf to few per leaf (in rather few pairs); opposite or sub-opposite; without noticeably twisted petiolules; obovate, symmetrical or nearly so; pinnately veined, without a continuous marginal nerve. Stipules present, persistent and conspicuous in mature leaves, or absent or early caducous or very inconspicuous in mature leaves; spinescent, or 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 small; hermaphrodite; pentamerous; coloured. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present; shortly 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 markedly irregular (with the lowermost sepal modified); members very imbricate. Corolla present; slightly irregular (the spreading, well developed, obovate petals slightly unequal); 5; without greatly reduced members; polypetalous. Petals sessile; imbricate; imbricate-ascending; yellow. Disk absent. The androecium comprising 10 members; members all free of one another (the filaments basally pilose); members all more or less equal in length to markedly unequal (then alternating longer and shorter); comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective; dehiscing introrsely. Ovary stipitate; free. Stigma small, but dilated (on the filiform style). Ovules few (2–3).

Fruit, seed and seedling. Fruit a two-valved pod (splitting down the middle of each valve); not internally septate; not noticeably winged; lanceolate, compressed, the valves membranous, not becoming woody. Seeds non-endospermic; with a straight or slightly oblique radicle; amyloid-negative; with galactomannan. Cotyledons of Type 2; epigeal.

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 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 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 straight in optical section; conspicuously pitted; medium-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; staining normally with safranin; thin.

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

Pollen ultrastructure. Tectum reticulate; finely to moderately regularly reticulate. Length of colpi greater than one half pole to pole distance (with a margocolpus).

Cytology. Basic chromosome number, x = 12. 2n = 24.

Species number and distribution. 4 species (H. brasiletto, H. campechianum, H. dinteri and H. souzanum). Central America, West Indies, tropical Africa.

Tribe. Caesalpinieae.

Comments. Widely cultivated.

Miscellaneous. Illustrations: • Haematoxylum campechianum: Baillon, Histoire des Plantes 2 (1870). • H. campechianum (with Sweetia fruticosa (Papilionoideae) as Ferreirea spectabilis): Nat. Pflanzenfam. III (1894). • Haematoxylum campechianum leaflet: detail of abaxial epidermis.

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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