Bauhinia

Taxonomy

Bauhinia C. Linnaeus Sp. Pl. 374. 1 Mai 1753.

Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.3.04.
Tribe: Cercideae.
Subtribe: Bauhiniinae.
Species Studied - Species in Genus: 98 studied; ca. 250 in genus.

Description

Fruit: A legume; unilocular; 3–37 cm long; 0.8–8 cm wide; 0.2–2 cm thick; length less than twice as long as width to more than 9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight to curved; not plicate; not twisted; asymmetrical; nearly circular to oblong, or linear; not inflated; flattened to compressed; without beak; long tapered at apex to tapered at apex; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; tapered at base to rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous, or ligneous; seed chambers externally invisible, or visible; margin constricted, or not constricted; margin without sulcus; margin plain, or embellished (occasionally); margin with thickened sutural areas; wing(s) absent; stipitate to substipitate; with the stipe 6–60 mm long; indehiscent, or with all layers dehiscing (breaking irregularly); splitting along suture(s). Dehiscence of valves along 1 suture, or both sutures; active, or passive (along dorsal then ventral or both simultaneously); with valves twisting (or open scissorlike into loose to tight coils). Replum invisible. Epicarp dull to glossy; monochrome; brown to purplish or reddish or grayish brown; with surface texture uniform; densely pubescent and indurate, or glabrous; with hairs erect; eglandular; without spines; nearly smooth, or not smooth; with elevated features; strongly veined, or not veined; reticulately veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present, or absent; surface not veined; 1-layered (?); without balsamic vesicles; without fibers; without reniform canals; spongy; ligneous to coriaceous. Endocarp present; visible; dull; opaque; monochrome; tan; without adhering pieces of testa; septate to nonseptate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 1–26; length parallel with fruit length to transverse to fruit length; neither overlapping nor touching; in 1 series (rarely irregulary arranged and embedded in pulp as in B. fassoglense or B. thonningii). Funiculus 1–15 mm long; of 1 length only; triangular; triangular, or straight to curved. Aril absent.

Seed: 4–35 mm long; 3–35 mm wide; 2.1–13 mm thick; not overgrown; angular, or not angular; symmetrical, or asymmetrical; ovate to circular, or oblong, or quadrangular, or rectangular, or irregular (with or without hilar notch); compressed to flattened; with surface smooth; without visible radicle and cotyledon lobes; without hilar sinus; without umbo on seed faces; without medial ridge on each face. Cuticle not exfoliating; not inflated; not wrinkled. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; glossy to dull; not modified by a bloom; colored; monochrome; brown to purplish or blackish brown to black; glabrous; smooth, or not smooth; with elevated features, or recessed features (rarely with tan pits along outer margin of face); rugose (and with or without fan arising from hilar regions or center of face); pitted with small separate pits; osseous to chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines present, or absent; inconspicuously to conspicuously concentric. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible, or fully concealed; concealed by funicular remnant; without faboid split; larger than punctiform; 1.3–50 mm long (from base to end of arm and arms of equal or unequal length and occupying up to 7/8 of seed circumference; reddish tan); with angular outline; V-shaped; subapical to radicle tip; not within corona, halo, or rim. Lens discernible, or not discernible (?); 0.2–1.5 mm long; with margins straight, or curved; oblong, or irregular; elliptic; not in groove of raphe; mounded; dissimilar color from testa (?); ?; black, or red, or tan; not within corona, halo, or rim. Endosperm present, or absent; not pluglike and not resembling tip of radicle; adnate to testa. Cotyledons smooth; both outer faces convex; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; partially concealing radicle; with lobes; with lobes overlapping, or not touching; with basal groin formed by lobes; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis straight; parallel to length of seed to oblique to length of seed (slightly); without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; centered between cotyledons. Plumule rudimentary; glabrous.

Distribution

Pantropic.

Pantropic New World and Old World; southern United States, Mexico, West Indies, Central America, and South America; Argentina, Peru, Brazil, Ecuador, and the Guianas; Southwest Asia, China, Japan, Africa, Madagascar, Indian Ocean, India, Indochina, Indonesia and the Philippines, Australia, Pacific, and New Guinea.
 

Generic Notes

Wunderlin et al. (1981 and reaffirmed in 1987) recognized "two main phyletic lines...one giving rise to the Bauhinia, Piliostigma, and Barklya groups and the other the Phanera group." These groups are represented in this study. Barklya F.J.H. von Mueller was recently transferred from the Sophoreae (Faboideae) to Bauhinia (Wunderlin, 1979). De Wit (1956) revised the Malaysian Bauhinieae, and the segregate genus Piliostigma Hockstetter was covered by Coetzer and Ross (1976b). Rugenstein and Lersten (1981) documented the presence of stomata on Bauhinia seeds and fruits, and Trivedi et al. (1980) studied the testa surface of six species.