| # The genera of Leguminosae-Caesalpinioideae and Swartzieae |

L. Watson and M.J. Dallwitz

### Trachylobium Hayne

~ Hymenaea verrucosa.

Type species: T. verrucosum (Gaertn.) Oliv.

Habit and leaf form. Trees; unarmed.

Phyllotaxy distichous. The leaves compound; bifoliolate; paripinnate. The leaflets leathery, few per leaf (only two); opposite or sub-opposite; petiolulate; with markedly twisted petiolules; markedly asymmetrical; pellucid-punctate, pinnately veined, with a predominant ‘midrib’ (this displaced towards the upper margin). Stipules absent or early caducous or very inconspicuous in mature leaves. Stipels absent.

Inflorescence and floral morphology. The inflorescences terminal; branched; of racemose units; panicles. The flowers not distichous. Bracts ovate or orbicular, concave, absent at anthesis. Bracteoles present; ovate or orbicular, caducous, small, not enclosing the flower buds; absent at anthesis; not valvate.

The flowers hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx, or in the calyx and in the corolla; white or green. Hypanthium present (short and thick). Calyx 4; covering the rest of the flower in bud; polysepalous; more or less regular; members very imbricate. Corolla present; slightly irregular, or very irregular; 3, or 5 (then three large and two vestiges); including greatly reduced members, or without greatly reduced members; polypetalous. Petals long clawed (the large ones), or clawed and sessile; imbricate; imbricate-ascending; white. Disk present and conspicuous. The androecium comprising 10 members; members all free of one another (the filaments basally villous); members all more or less equal in length; comprising only fertile stamens. Fertile stamens 10. Anthers oblong, uniform attached well above the base of the connective; dehiscing longitudinally. Ovary shortly stipitate; free to eccentric, with the stipe adnate. Stigma small, but dilated (the style slender). Ovules few, or numerous, or solitary.

Fruit, seed and seedling. Fruit indehiscent; drupaceous; ovoid-oblong, leathery and very coarsely verrucose-rugose, not becoming woody. The mature valves without prominent venation. Seeds non-endospermic; not arillate; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons not flat; epigeal.

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

Pollen ultrastructure. Tectum punctate; smooth punctate, or puncticulate.

Cytology. Basic chromosome number, x = 12.

Species number and distribution. 1 species (T. gaertnerianum, = T. verrucosum). Tropical East Africa, Madagascar, Mauritius.

Tribe. Detarieae.

Comments. Widely cultivated.

Miscellaneous. Illustrations: • Trachylobium verrucosum: 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: 4th August 2019. delta-intkey.com’.

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