Faidherbia

Taxonomy

Faidherbia A.J.B. Chevalier Rev. Bot. Appliq. 14: 876. 1934.

Subfamily: Mimosoideae.
Phylogenetic Number: 2.5.08.
Tribe: Ingeae.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume; unilocular; 5.8–35 cm long; 1.4–5 cm wide; 0.6–1.3 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; curved to 1-coiled, or contorted; not plicate; not twisted; symmetrical, or asymmetrical; C-shaped, or falcate; with both sutures parallelly curved; not inflated; compressed; without beak; rounded at apex to tapered at apex; oblique with longitudinal axis of fruit; rounded at base to tapered at base; oblique with longitudinal axis of fruit; with the apex and base uniform in texture; ligneous (when mature), or fleshy (when young, only the epicarp); seed chambers externally faintly visible, or invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; substipitate; with the stipe up to 5 mm long; indehiscent (remaining attached to sutures). Replum invisible. Epicarp dull; monochrome; reddish brown (when dry), or orange (when fresh); with surface texture uniform; glabrous to pubescent and indurate (to puberulent); with hairs erect; with simple hairs; eglandular; without spines; smooth, or not smooth; with elevated features; not veined; not tuberculate; dotted (when young apparent, when mature with or without visible veins, parallel veined from ventral margin but anastomosing before reaching dorsal margin); 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; without reniform canals; fibrous throughout; ligneous. Endocarp present; visible; dull; opaque; monochrome; tan; smooth; without adhering pieces of testa; nonseptate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 10–22; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus to 3 mm long; of 1 length only; thick; straight. Aril absent.

Seed: 6–12 mm long; 3.8–8 mm wide; 2.2–3.4 mm thick; not overgrown; not angular; symmetrical; oblong to circular (sub); 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; brown; glabrous; smooth; osseous. Pleurogram present; 75–100 %. Pseudopleurogram absent. Fracture lines present. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible; without faboid split; punctiform; subapical to radicle tip; recessed; not within corona, halo, or rim. Lens discernible; 0.4–0.5 mm long; with margins straight; linear; not in groove of raphe; recessed (groove); same color as testa; darker than testa; brown; not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; adnate to testa. Cotyledons smooth; both outer faces flat; 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; 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; straight with embryonic axis; centered between cotyledons. Plumule well developed; glabrous.

Distribution

Generic Notes

Faidherbia fruits and seeds were thoroughly studied and illustrated by Nongonierma (1978, 1979) as Acacia albida Delile. Scott and Smith (1998) studied cotyledon architure and anatomy in this genus. Neither fruit nor seed characters support this segregate monotypic genus.