| # The genera of Leguminosae-Caesalpinioideae and Swartzieae |

L. Watson and M.J. Dallwitz

### Ceratonia L.

Type species: C. siliqua L.

Habit and leaf form. Trees; unarmed.

Phyllotaxy spiral. The leaves compound; pinnate; paripinnate. The leaflets few per leaf; leathery, opposite or sub-opposite; petiolulate; symmetrical or nearly so; pinnately veined, with a predominant ‘midrib’. Stipules absent or early caducous or very inconspicuous in mature leaves; membranous. Stipels absent.

Inflorescence and floral morphology. The inflorescences lateral on the year-old branches; unbranched, or branched; when branched, of racemose units; simple racemes, or fascicles. The flowers not distichous. Bracts absent at anthesis (caducous, minute). Bracteoles present; small, not enclosing the flower buds (minute); persistent beyond anthesis.

The flowers small; hermaphrodite and unisexual (the plants dioecious or polygamodioecious); not pentamerous throughout; departing from pentamery in the corolla and in the androecium. Hypanthium present to absent, the androecium hypogynous; very short; saucer-shaped (infilled with the nectarial disk). The perianth exclusively sepaline. Calyx small, 5; polysepalous; members imbricate. Corolla absent. Disk present and conspicuous. The androecium comprising 5 members; members all free of one another; members all more or less equal in length; comprising only fertile stamens. Fertile stamens 5. Anthers attached well above the base of the connective; dehiscing introrsely to laterally; dehiscing longitudinally. Ovary shortly stipitate (in the middle of the disk); free. Stigma dilated (on the short, stout style). Ovules numerous.

Fruit, seed and seedling. Fruit indehiscent (edible); curved; internally septate; not becoming woody. The mature valves without prominent venation. Seeds 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.

Wood anatomy. Wood with septate fibres, or without septate fibres; not storied.

Pollen ultrastructure. Tectum punctate; smooth punctate, or puncticulate. Length of colpi greater than one half pole to pole distance (tetracolporate).

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

Species number and distribution. 2 species (C. oreothauma and C. siliqua). Mediterranean, Arabia, northeast Africa.

Tribe. Cassieae.

Comments. Widely cultivated.

Miscellaneous. Illustrations: • Ceratonia siliqua: Nat. Pflanzenfam. III (1894). • Ceratonia siliqua, 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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