Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.4.19.
Tribe: Detarieae.
Group: Hymenostegia.
Species Studied - Species in Genus: 6 studied; 9 in genus.
Fruit: A legume; unilocular; 4–12 cm long; 2–6 cm wide; 0.4–0.7 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; asymmetrical; with nearly 1 straight and 1 curved suture; widest near middle or D-shaped, or widest near apex (stated as "oblong"); not inflated; flattened; without beak; long tapered at apex to tapered at apex; aligned with longitudinal axis of fruit to right-angled with longitudinal axis of fruit; tapered at base to rounded at base; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous to ligneous (or nearly so); seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; substipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; passive (seed remaining with one valve excluding endocarp and falling as a unit). Replum invisible. Epicarp nearly glossy; monochrome; tannish brown; with surface texture uniform; glabrous; 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 absent. Endocarp present; visible; dull; opaque; monochrome; tannish brown to white; without adhering pieces of testa; curling up at apex and separating from 1 epicarp, nonseptate; not exfoliating; entire. Seed(s) 1 (apical); length parallel with fruit length. Funiculus 0.1–20 mm long; of 1 length only; flattened; curved to plicate (once). Aril absent (arillike funicular remnant present).
Seed: 20–55 mm long; 13–20 mm wide; 2–7 mm thick; not overgrown; not angular; symmetrical; elliptic to oblong; 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; blackish brown; glabrous; smooth; osseous. Pleurogram absent. Pseudopleurogram absent. Fracture lines present; not stated. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; fully concealed; concealed by funicular remnant; without faboid split; larger than punctiform; 0.1–1.5 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 present (trace); trace; not pluglike and not resembling tip of radicle; restricted to region of embryo (around cotyledon split and radicle tip). 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; 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.