The genera of Leguminosae-Caesalpinioideae & Swartzieae
Type species: B. insignis Humbert.
Habit and leaf form. Xeromorphic trees (the branchlets consisting of cladodes with gland-like, peltate scales); unarmed.
Phyllotaxy distichous. The leaves compound; early caducous, bifoliolate. The leaflets few per leaf (two); petiolulate; palmately nerved (ftom the base). Stipules absent or early caducous or very inconspicuous in mature leaves (minute); membranous. Stipels absent.
Inflorescence and floral morphology. The flowers aggregated into inflorescences (comprising short spiciform racemes of 10–20 flowers, borne in notches at the nodes of the cladodes). The inflorescences axillary; unbranched; simple racemes. The flowers not distichous. Bracts minute. Bracteoles present (these minute); small, not enclosing the flower buds; not valvate; free.
The flowers small (4–5 mm long); hermaphrodite; only slightly irregular; not pentamerous throughout; departing from pentamery in the corolla. Hypanthium absent, the androecium hypogynous. The perianth exclusively sepaline (though the staminodes could be mistaken for petals). Calyx present; 5; gamosepalous (campanulate, with 5 triangular, obtuse teeth and minute scales outside); more or less regular; members not imbricate (valvate). Corolla absent. Disk absent. The androecium comprising 10 members; not declinate; members all free of one another (the fertile stamens internal to and opposite the petaloid staminodes); members markedly unequal (those of the staminal whorl exceeding the staminodal one); including staminodia. The staminodia 5; petaloid, narrowly linear-obovate. Fertile stamens 5. Anthers attached well above the base of the connective (medifixed, versatile); dehiscing longitudinally. Ovary sessile or subsessile; free. Stigma capitate, sessile, dilated. Ovules solitary to few.
Fruit, seed and seedling. Fruit a two-valved pod (flattened and discoid, obliquely sub-circular to oblong). Seeds arillate (with a crescentic hilum, cf. Bauhinia); with a straight or slightly oblique radicle. Cotyledons flat (thick).
Pollen ultrastructure. Tectum reticulate.
Species number and distribution. 1 species (B. insignis). Madagascar.
Miscellaneous. Illustrations: • B. insignis: flower, fruit and seed (Wunderlin & Larsen, 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: 22nd March 2017. delta-intkey.com/caes’.