Subfamily: Faboideae.
Phylogenetic Number: 3.10.29.
Tribe: Phaseoleae.
Subtribe: Glycininae.
Species Studied - Species in Genus: 2 studied; 5 in genus.
Fruit: A legume; unilocular; 2.3–2.8 cm long; 0.7–1 cm wide; 0.5 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; not plicate; not twisted; asymmetrical; lanceolate, or linear; with both sutures nearly straight; not inflated; compressed; without beak, or with beak; straight, or declined; with solid beak the same color and texture as fruit; tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; tapered at base, or rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; 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 to brown; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; sericeous; with pubescence golden, or white; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; smooth; not veined; not tuberculate; not exfoliating, or exfoliating in part (rarely); without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; 2-layered; without balsamic vesicles; without fibers; without reniform canals; with vitriol layer over solid layer, or spongy layer over solid layer; coriaceous. Endocarp present; visible; dull; opaque; mottled, or bichrome; white, or white and brown (over seed chambers); with mottling over seed chambers; with yellow overlay; smooth; without adhering pieces of testa; subseptate; with septa thin (tissue paper-like), flexible; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1–2; length oblique to fruit length, or transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 1.5–3 mm long; of 1 length only; flattened; straight, or triangular. Aril present; dry; when dry rim-aril and tongue-aril; entire; cream.
Seed: 8.5–9.5 mm long; 6.5–7.5 mm wide; 3–3.2 mm thick; not overgrown; not angular; asymmetrical; irregularly reniform; compressed; 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; reddish brown; glabrous; not smooth; with recessed features, or recessed features and elevated features; wrinkled; pitted with small separate pits; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; partially concealed; concealed by aril; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; larger than punctiform; 1.3–1.5 mm long; with curved outline; elliptic; marginal according to radicle tip; recessed; within halo; halo darker than testa. Lens discernible; 0.1–1 mm long; with margins curved; elliptic; not in groove of raphe; confluent with hilum; flush; similar color as testa; darker than testa; not within corona, halo, or rim. 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; yellow; 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; triangular; lobe tip straight; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons. Plumule moderately developed; glabrous.