Subfamily: Faboideae.
Phylogenetic Number: 3.6.04.
Tribe: Amorpheae.
Species Studied - Species in Genus: 15 studied; 15 in genus.
Fruit: A legume; unilocular; 0.4–1.05 cm long; 0.15–0.45 cm wide; 0.14–0.18 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx; with calyx equal in length to fruit, or shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight to curved (to slightly curved); not plicate; not twisted; asymmetrical; falcate, or oblong; with 1 straight and 1 curved suture, or both sutures parallelly curved, or both sutures unequally curved; widest near middle or D-shaped, or widest near apex; not inflated; compressed; without beak, or with beak; with solid beak the same color and texture as fruit; rounded at apex; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; tapered at base; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous, or fragile, thinner than chartaceous, like Trifolium; seed chambers externally visible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; substipitate, or nonstipitate; indehiscent. Replum invisible. Epicarp dull; monochrome (sometimes with conspicuously darker colored glandular dots); brown, or tan; with surface texture uniform, or not uniform, with patches of different texture not restricted to the base and apex; glabrous, or glabrate, or pubescent and indurate; with hairs erect; with 1 type of pubescence; puberulent; with pubescence gray; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; glandular, or eglandular; with glandular dots; without spines; not smooth; with elevated features, or recessed features; not veined; not tuberculate; faintly wrinkled; punctate (because of empty glandular dots); not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; glassy beads (reddish to dark-brown); coriaceous. Endocarp present; visible; dull to glossy; opaque; monochrome; reddish brown, or tan; smooth, or vitriol (because of glandular exudates); without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1; length parallel with fruit length. Funiculus filiform, or thick; straight. Aril present, or absent; dry; when dry rim-aril; entire; light tan.
Seed: 2.5–5 mm long; 1.6–3 mm wide; 1.1–1.3 mm thick; not overgrown; not angular; asymmetrical; D-shaped, or elliptic, or oblong (all with radicular beak); compressed; 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; glossy (because of glandular exudate), or dull; not modified by a bloom; colored; monochrome; brown (reddish to orange to olive), or tan, or black; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Raphe visible; from hilum to lens, or hilum to near base of seed and terminating; not bifurcating; darker than testa; tan, or brown (dark to light); flush. Hilum present; visible; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform; between cotyledon and radicle lobe; recessed; within rim; rim color of testa (essentially). Lens discernible, or not discernible; with margins curved; circular, or elliptic; not in groove of raphe; adjacent to hilum; 1.5 mm from hilum; barely mounded; dissimilar color from testa; darker than testa; dark brown; not within corona, halo, or rim. Endosperm present; thick; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa, or embryo. 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 (barely); split over radicle; with lobes; with lobes not touching; with the interface division terminating at base of radicle; without margins recessed; green, or tan; inner face flat; glabrous on inner face. Embryonic axis deflexed; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; lobe tip curved; deflexed and parallel to cotyledon width; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary to moderately developed; glabrous.
United States and Canada.
New World; Canada to United States to Mexico.