Flora of North America species comparison

alternate, odd-pinnate, pulvinate;

stipules present, persistent, sessile, divergent from stem, striate, triangular-ovate, not produced proximal to point of insertion; long-petiolate, petiole and rachis canaliculate, pubescent;

leaflets 3, stipels persistent, striate, often curved, linear, blades 1.3–5.6(–7.2) cm, membranous to papery, margins entire or lobed, sometimes basally lobed, surfaces sericeous or strigose.

1–12(–22)-flowered, axillary, pseudoracemes, rachis much contracted, with 1–6(–11)-flowering nodes, nodes often swollen, glandular, each bearing at most 2 flowers;

primary bracts early deciduous or absent;

secondary bracts subtending pedicels, persistent, ovate to lanceolate;

bracteoles persistent, rigid and striate, lanceolate, equal to or longer than calyx tube.

angular.

mostly shorter than calyx tube, thickened in fruit.

papilionaceous;

calyx campanulate, 1.3–7 mm, lobes 4 (due to connation of 2 adaxial lobes into 1 acute-attenuate lobe), abaxial lobe more narrowly triangular and often longest, lateral lobes triangular, adaxial lobes connate into acute lobe;

corolla pink or pinkish, banner often with yellowish maculae, keel pinkish, tip (beak) dark purple, 3.6–15 mm;

wings oblong, not projected beyond distal bend of keel;

keel petals connate along upper margin, incurved, with a prominent gibbosity along upper margin proximal to beak;

stamens 10, diadelphous;

anthers sub-basifixed, uniform;

pollen tricolporate;

ovary sessile, arched, sparsely to densely strigose, at base surrounded by a nectariferous sheath;

style incurved like the keel, often becoming twisted, jointed at the first (proximal) curve, distinctly incrassate and flattened, distal portion introrsely bearded;

stigma terminal and introrse.

legumes, sessile, held horizontally or somewhat drooping, linear or slightly curved, cylindric to subcylindric, dehiscent with twisting valves, sericeous, strigose, glabrate, or glabrous.

4–10, spherical or oblong, subquadrate or reniform, ends truncate, usually covered with a cellular layer;

hilum oblanceolate, elongated 1/2 length of seed, rim-aril and hilar tongue much reduced, lens distinct and divided;

seedlings with epigeal germination.

, annual or perennial, unarmed, to 2 m. Stems slender, flexible, trailing or climbing, often branching at proximal nodes, not woody, sometimes lignescent at base, sparsely to densely short-pilose.

= 11.