Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.4.09.
Tribe: Detarieae.
Group: Hymenostegia.
Species Studied - Species in Genus: 3 studied; 4 in genus.
Fruit: A legume; unilocular; 8.5–19(–20) cm long; 3–9 cm wide; 0.4–1 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; compressed; without beak; tapered at apex; oblique with longitudinal axis of fruit, or right-angled with longitudinal axis of fruit; rounded at base; oblique with longitudinal axis of fruit to right angled 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 6–15 mm long; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; passive. Replum invisible. Epicarp dull; monochrome; reddish brown to brown; with surface texture uniform; velvety pubescent and indurate; with hairs erect; eglandular; without spines; not smooth; with elevated features; veined; transversely veined relative to fruit length to obliquely veined relative to fruit length; not tuberculate; exfoliating in part; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; surface not veined; 2-layered; without balsamic vesicles; without fibers; without reniform canals; with solid layer over spongy layer (stated as "dark over solid tan layer"); ligneous. Endocarp present; visible; dull; opaque; without adhering pieces of testa; nonseptate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 2; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.1–5 mm long; of 1 length only; thick; straight. Aril absent.
Seed: 28–31 mm long; 22–25 mm wide; 2–3 mm thick; not overgrown; not angular; symmetrical; nearly circular; 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; brown; glabrous; not smooth; with recessed features; minutely pitted with small separate pits; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible; without faboid split; larger than punctiform; 0.1–3.5 mm long; not stated; apical at apex of radicle tip; flush; 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; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis straight; 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.
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.