Baikiaea

Taxonomy

Baikiaea G. Bentham In Bentham et J. D. Hooker, Gen. 1: 581. 19 Oct 1865.

Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.4.40.
Tribe: Detarieae.
Group: Detarium.
Species Studied - Species in Genus: 4 studied; 4 in genus.

Description

Fruit: A legume; unilocular; 7–60 cm long; 3–12 cm wide; 0.5–1.5 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; straight; not plicate; not twisted; symmetrical, or asymmetrical; oblong; with 1 straight and 1 curved suture; widest near apex; not inflated; flattened; without beak; long tapered at apex; aligned with longitudinal axis of fruit; tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; ligneous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate; with the stipe 6–50 mm long; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; active; with valves separately enrolling. Replum invisible. Epicarp dull; monochrome; dark to light reddish brown; with surface texture uniform; densely pubescent and indurate (velvety); with hairs erect; with simple hairs; eglandular; without spines; smooth; not veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; surface not veined; 3-layered; without balsamic vesicles; without fibers; without reniform canals; with spongy layer over 2 distinct solid layers; ligneous. Endocarp present; visible; dull; opaque; monochrome; brown; without adhering pieces of testa; nonseptate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 1–7; length oblique to fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.1–2 mm long; of 1 length only; flattened; straight. Aril present, or absent (whitish); fleshy (texture not stated); when fleshy topknotlike; entire; covering less than 1/2 of seed (degree of coverage not stated).

Seed: 20–60 mm long; 15–30 mm wide; 5–12 mm thick; not overgrown; not angular; symmetrical, or asymmetrical; elliptic to circular, or D-shaped; 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; dull; not modified by a bloom; colored; monochrome; dark brown to reddish brown; glabrous; smooth, or not smooth; with elevated features, or recessed features; rugose; pitted with small separate pits; osseous. Pleurogram absent. Pseudopleurogram absent. Fracture lines present, or absent; concentric. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; fully concealed; concealed by funicular remnant; without faboid split; larger than punctiform; 0.1–3.5 mm long; with curved outline; elliptic; apical at apex of radicle tip to subapical to radicle tip; raised; 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 entire 180 degrees from base of radicle; similar at apex; partially concealing radicle (only tip exposed); notched at radicle and split over radicle (somewhat); 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; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; centered between cotyledons. Plumule rudimentary; glabrous.

Distribution

Tropical Africa.

Old World; Tropical Africa.
 

Generic Notes

The wood of B. plurijuga is known as Rhodesian-teak (Ross, 1977b).

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.