Subfamily: Faboideae.
Phylogenetic Number: 3.10.61.
Tribe: Phaseoleae.
Subtribe: Phaseolinae.
Species Studied - Species in Genus: 1 studied; 1 in genus.
Fruit: A legume; unilocular; 3.7–5 cm long; 1.6–1.8 cm wide; 0.6–0.8 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight, or curved (slightly); not plicate; not twisted; asymmetrical; irregular; with 1 straight and 1 curved suture, or both sutures unequally curved; widest near middle or D-shaped; not inflated; compressed; with beak; hooked; with solid beak the same color and texture as fruit; short tapered at apex; oblique with longitudinal axis of fruit; tapered at base, or short tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous to coriaceous; seed chambers externally visible, or invisible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin embellished; margin with thickened sutural areas, or thickened sutural areas and prickles; wing(s) absent; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves twisting. Replum invisible. Epicarp dull; monochrome; tan; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; short puberulent; with pubescence white; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; veined; reticulately veined; not tuberculate; verrucose-rugose; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; trace; surface not veined; 1-layered; without balsamic vesicles; without reniform canals; solid; chartaceous. Endocarp present; visible; glossy; opaque; monochrome; tan to white; smooth; without adhering pieces of testa; subseptate; with septa thin (tissue paper-like), flexible; with septa eglandular; chartaceous; exfoliating in part; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 2–4; length oblique to fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.5–2 mm long; of 1 length only; flattened; triangular. Aril present; fleshy; when fleshy hippocrepiform rim-aril; fimbriate; covering less than 1/2 of seed; with tongues (or flap) on lips of 2-lipped rim-aril; with 1 tongue or flap on 1 lip of 2-lipped rim-aril; cream.
Seed: 8–18 mm long; 5.5–11.5 mm wide; 3.8–7.5 mm thick; not overgrown; not angular; asymmetrical; elliptic to irregular to ovate; nearly terete to compressed; with surface smooth; with visible radicle and cotyledon lobes; without external groove between 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, or mottled; with infrequent mottles; brown, or cream; with brown overlay (darker); glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; fully concealed; concealed by aril; without faboid split; larger than punctiform; 8–12.5 mm long; with straight outline; linear; marginal according to radicle tip; recessed; within corona, or not within corona, halo, or rim; corona color darker than testa. Lens discernible; 1.8–2 mm long; with margins straight, or curved; linear; elliptic; not in groove of raphe; confluent with hilum; mounded; similar color as testa, or dissimilar color from testa; darker than testa; brown, or tan; within rim; rim color of testa, or darker than testa. 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; notched at radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; white to tan to brown; inner face flat; glabrous on inner face. Embryonic axis oblique; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; lobe tip curved; oblique to cotyledons; centered between cotyledons; less than 1/2 length of cotyledons. Plumule well developed; glabrous.