Subfamily: Faboideae.
Phylogenetic Number: 3.10.04.
Tribe: Phaseoleae.
Subtribe: Erythrininae.
Species Studied - Species in Genus: 2 studied; 2 in genus.
Fruit: A legume; unilocular; 10–18 cm long; 3–5.3 cm wide; 0.4–0.6 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; asymmetrical; samaroid; with both sutures unequally curved; not inflated; flattened; without beak; rounded at apex to truncate at apex; oblique with longitudinal axis of fruit; tapered at base to rounded at base; oblique with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous and leathery; seed chambers externally visible; margin not constricted; margin without sulcus; margin embellished; margin with thickened sutural areas (especially dorsally), or wing(s); wing(s) present; wing(s) 1; wing(s) 30–53 mm wide (and 90–110 mm long); wing(s) samaroid; wing(s) basal; nonstipitate; indehiscent. Replum invisible. Epicarp dull; monochrome; tan; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; pilose to tomentose; with pubescence golden; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; veined; reticulately veined; not tuberculate; exfoliating in part; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 3-layered; without balsamic vesicles; without fibers; without reniform canals; with solid layer over spongy layer over solid layer; coriaceous. Endocarp present; visible; dull; opaque; mottled; tan; with mottling more or less uniform (dark and fine); with brown overlay; smooth; without adhering pieces of testa; nonseptate; chartaceous; exfoliating in part; remaining fused to mesocarp and epicarp; with wing(s) extending into epicarp; entire. Seed(s) 1; length parallel with fruit length, or oblique to fruit length. Funiculus 4 mm long; thick; straight. Aril absent.
Seed: 24–38 mm long; 19–27 mm wide; 5–6 mm thick; not overgrown; not angular; asymmetrical; irregularly reniform; flattened; with surface wrinkled; 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; mottled; with frequent mottles; reddish brown; with brown overlay (dark); glabrous; not smooth; with elevated features; wrinkled, or wrinkled and warty; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe visible; from hilum to near base of seed and terminating; not bifurcating; color of testa; raised. Hilum present; visible; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; larger than punctiform; 1.5–2.5 mm long; with curved outline; elliptic; marginal according to radicle tip; recessed; within halo; halo darker than testa. Lens not discernible. Endosperm absent. Cotyledons not smooth; wrinkled; 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; notched at radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis right angled, or oblique; perpendicular to length of seed, or oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; linear; lobe tip straight; deflexed and parallel to cotyledon width, or oblique to cotyledons; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.