The genera of Leguminosae-Caesalpinioideae & Swartzieae
Type species: B. santosii Cowan.
Habit and leaf form. Trees (5–13 m); unarmed.
The leaves compound; pinnate; paripinnate. The leaflets few per leaf (2–3 jugate); opposite or sub-opposite; petiolulate; with markedly twisted petiolules; without a continuous marginal nerve. Stipules present, persistent and conspicuous in mature leaves (thick); membranous; connate (intrapetiolar). Stipels absent.
Inflorescence and floral morphology. The inflorescences axillary and terminal; branched; panicles. The flowers not distichous. Bracts absent at anthesis (caducous, round, concave). Bracteoles present (round, concave, pedicellate); small, not enclosing the flower buds; absent at anthesis; not valvate; free.
The flowers hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx. Floral tube length relative to total hypanthium + calyx length about 0.5. Hypanthium present. The perianth comprising distinct calyx and corolla. Calyx 4; covering the rest of the flower in bud; more or less regular; members imbricate. Corolla present; regular to slightly irregular; 5; without greatly reduced members; polypetalous. Petals shortly clawed; imbricate; imbricate-ascending. The androecium comprising 10 members; with united members (forming a short basal tube); members all more or less equal in length; comprising only fertile stamens. Fertile stamens 10. Anthers versatile, attached well above the base of the connective; dehiscing longitudinally. Ovary stipitate; eccentric, with the stipe adnate (this partly free). Stigma not dilated (capitate, the style filamentous and exserted). Ovules numerous (?).
Fruit, seed and seedling. Fruit a two-valved pod (flattened, glabrous); straight; without markedly twisting or enrolling valves; with a thinly crustaceous exocarp, not becoming woody. The mature valves with conspicuous, prominent, raised venation; conspicuous venation oblique and reticulate, not predominantly longitudinal. Seeds arillate (with a tiny, annular aril around the hilum); with a straight or slightly oblique radicle.
Transverse section of lamina. Druses absent from the mesophyll. Mesophyll secretory cavities (gland-dots) common; without a lining of epithelium. 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 not seen. 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; not conspicuously pitted; medium-thick. Stomata adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic (the subsidiaries often asymmetric). Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating; not conspicuously pitted in optical section; staining normally with safranin; of medium thickness.
Pollen ultrastructure. Tectum irregularly bullate.
Species number and distribution. 1 species (B. santosii). Brazil.
Tribe. Detarieae; Amherstieae clade of Bruneau et al. (2008).
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. delta-intkey.com/caes’.