Guibourtia

Taxonomy

Guibourtia J.J. Bennett J. Proc. Linn. Soc., Bot. 1: 149. Mar 1857.

Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.4.35.
Tribe: Detarieae.
Group: Crudia.
Species Studied - Species in Genus: 6 studied; 14 in genus.

Description

Fruit: A legume; unilocular; 2–5 cm long; 1.5–3 cm wide; 0.2–1 cm thick; length less than twice as long as width; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; asymmetrical; elliptic, or obovate; not inflated; flattened; without beak; tapered at apex; aligned with longitudinal axis of fruit to right-angled with longitudinal axis of fruit; rounded at base; right angled with longitudinal axis of fruit; with the apex and base uniform in texture; membranous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate to substipitate; with the stipe 6 mm long; indehiscent. Replum invisible. Epicarp dull; monochrome; blackish brown to brown; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; veined; transversely veined relative to fruit length; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; surface not veined; 1-layered; without balsamic vesicles; with fibers, or without fibers; without reniform canals; mealy, or solid (either solid or transverse fibers embedded in mealy tissue); coriaceous. Endocarp present; visible; sheen not stated; opaque; monochrome; brown; without adhering pieces of testa; nonseptate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 1–2; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.1–10 mm long; of 1 length only; nearly thick; 1- plicate, or straight (or nearly so). Aril present, or absent; dry ("smooth, brown when dry"); when dry caplike; entire; covering less than 1/2 of seed to entire seed.

Seed: 10–24 mm long; 10–17 mm wide; 0.2–6 mm thick; not overgrown; not angular; symmetrical; oblong; compressed; 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; not modified by a bloom; colored; monochrome; dark reddish brown to black; glabrous; smooth, or not smooth; with elevated features, or recessed features; rugose; minutely pitted with small separate pits; osseous to coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; fully concealed; concealed by funicular remnant; without faboid split; larger than punctiform; 0.1–1 mm long; shape not stated; marginal according to radicle tip; recessed; not within corona, halo, or rim. Lens not discernible. Endosperm absent. Cotyledons smooth; both outer faces convex; both the same thickness; both more or less of equal length; not folded; margin not entire 180 degrees from base of radicle (notched); similar at apex; completely concealing radicle; split over radicle; 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; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; centered between cotyledons. Plumule rudimentary; glabrous.

Distribution

Generic Notes

Barneby (1996) reviewed the American member of this genus, and concluded that there is but a single New World species, G. hymenaeifolia. Barneby's results combined with Cowan and Polhill's (1981a) species count of 13 for Africa yielded the species count that we are using. Guibourtia hymenaeifolia is unusual because the radicle tip points toward the basal end of the seed, not to the hilar or apical end. Arils of G. coleosperma may be used in making a drink (White, 1962). Watson and Dallwitz (1983) reported fruits to be "unilaterally winged".

Tribal Notes

Tribe Detarieae

Bruneau et al. (2000) carried out extensive phylogenetic analyses of tribes Amherstieae and Detarieae. They concluded that they form a single monophyletic group. Therefore, they supported Polhill's (1995a, 1995b) decision to unite the two tribes.