Plants annual or perennial herbs, from short taproots, sometimes climbing on other vegetation. Stems trailing or climbing, twining, branched, sometimes rooting at the nodes, unarmed, moderately to densely pubescent with short, downward-curved to downward-angled and sometimes also more or less spreading hairs, these slender to somewhat tapered from the base, but lacking a bulbous base. Leaves sometimes drooping and folding at night, pinnately trifoliate, mostly long-petiolate, the petiole hairy. Stipules 2–4(–5) mm long, narrowly ovate-triangular, herbaceous to papery, appearing basally attached and somewhat spreading, mostly persistent, strongly parallel-veined; stipels 0.5–1.0(–1.5) mm long. Leaflets lanceolate to ovate, the lateral ones sometimes appearing asymmetrically rhombic or pear-shaped, entire or with a basal lobe. Inflorescences very short axillary racemes (rarely only a solitary flower), appearing as small headlike or umbellate clusters at the tip of a stalk that usually is much longer than the subtending leaf, the very short flower stalks with small bracts at the base, each flower also closely subtended by 2 small bractlets. Calyces with the tube bell-shaped, 2-lipped, the upper 2 lobes fused with only a shallow notch at the tip, the lower 3 lobes triangular, unequal, the lowermost lobe somewhat narrower and longer than the others, often as long as or longer than the tube. Corollas papilionaceous, pink to lavender (the keel sometimes darker purple), rarely white, often fading to green or yellow, the petals cordate or abruptly tapered to an often relatively broad stalklike base, the banner broadly ovate to nearly circular, rounded to shallowly notched at the tip, abruptly arched upward above the midpoint but generally appearing hooded over other petals, the wings oblong, shorter than the keel, the keel widest at the midpoint, abruptly constricted above the midpoint into a blunt, upward-arched beaklike tip that is slightly to strongly twisted to the side. Stamens 10, 9 of the filaments fused to above the midpoint and 1 filament more or less free, the anthers small, attached at or near the base, all similar in size. Ovary appearing arched, sessile, the style curved, jointed above the midpoint, bearded on upper side, the stigma terminal and capitate. Fruits legumes, linear, not or only slightly flattened, sessile, short-tapered on the lower side to a short slender beak, the margins otherwise parallel, glabrous or appressed-hairy, papery in texture, dehiscent, the valves becoming spirally twisted during dehiscence, 3–10-seeded. Seeds subcylindric, rectangular in outline, slightly flattened, the surface brown, often mottled with darker brown or purplish brown, smooth or minutely pubescent with white-woolly patches of hairs. Three species, North America, mostly in the U.S.

Strophostyles is very similar and probably closely related to Phaseolus, differing mainly in the twisted (vs. coiled) nearly vertical keel, lack of hooked hairs, short flower stalks, and somewhat swollen nodes of the inflorescence. Although palatable to deer and livestock, Strophostyles species generally are not abundant enough to be considered important forage plants. The genus sometimes is planted for erosion control.