The genera of Leguminosae-Caesalpinioideae & Swartzieae
Type species: B. syringifolia F. Muell.
Habit and leaf form. Trees; unarmed.
The leaves ostensibly simple (unifoliolate, petiolate, cordate-acuminate, entire, the venation almost palmate); palmately veined. Stipules absent or early caducous or very inconspicuous in mature leaves (small, ovate, deciduous); membranous; not connate.
Inflorescence and floral morphology. The inflorescences axillary (racemes), or terminal (then paniculate); unbranched, or branched; when branched, of racemose units; simple racemes, or panicles. Bracts persistent beyond anthesis (but very small). Bracteoles absent; absent at anthesis.
The flowers hermaphrodite; pentamerous, or not pentamerous throughout; departing from pentamery in the corolla; coloured. Hypanthium present to absent, the androecium hypogynous (?); if present, shortly cupular. Calyx 5 (the lobes obtuse); open before anthesis, not covering the rest of the flower in bud; gamosepalous; markedly irregular (truncate or irregularly 5-dentate); members not imbricate. Corolla present (the petals about twice as long as the calyx); slightly irregular (the petals nearly equal, but the posterior one broader); 5, or 5–6 (i.e., to 6 partite); without greatly reduced members; polypetalous. Petals long clawed (all of them); imbricate; imbricate-ascending; yellow. The androecium comprising 10 members; members all free of one another; members all more or less equal in length (and longer than the petals); comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective (sagittate); dehiscing longitudinally. Ovary stipitate; free. Stigma minute, not dilated. Ovules few.
Fruit, seed and seedling. Fruit a two-valved pod (flat, tardily dehiscent); without markedly twisting or enrolling valves; thin, not becoming woody. The mature valves with conspicuous, prominent, raised venation, or without prominent venation; conspicuous venation olique or reticulate, not predominantly longitudinal. Seeds endospermic; arillate (the hilum crescentic); with an inflexed radicle (embryo somewhat curved). Cotyledons flat; epigeal.
Wood anatomy. Wood storied; without normal intercellular canals; without traumatic canals.
Cytology. Basic chromosome number, x = 13. 2n = 26.
Species number and distribution. 1 species (B. syringifolia). Australia.
Comments. Widely cultivated.
Formerly placed in Sophorieae or Cadieae, but inseparable from Bauhinia s. str. in terms of the present descriptions.
Miscellaneous. Illustrations: • B. syringifolia, flower (Wunderlin & Larsen, 1981). • B. syringifolia: www.plantillustrations.org.
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’.