Plants annual, biennial, or perennial, subacaulescent to caulescent, (0.4–)1–100 cm, glabrous or pubescent; from superficial or slightly subterranean root-crown. Stems prostrate, creeping, decumbent, ascending, or erect, glabrous, strigulose, villosulous, or pilose. Leaves 1–17 cm; stipules (1–)2–7 mm, submembranous; leaflets (3–)11–27(or 29), blades suborbiculate, elliptic, oblong, ovate, obovate, lanceolate, oblanceolate, or linear, (1–)2–21(–25) mm, apex acute to emarginate, surfaces glabrous, glabrate, strigose, strigulose, strigulose-villosulous, pilosulous, tomentulose, or silvery-silky. Peduncles 0.5–11(–14) cm. Racemes (2 or)3–35(–48)-flowered, flowers ascending or spreading; axis (0.3–)0.5–18(–26) cm in fruit, elongating only slightly; bracteoles usually 0. Flowers 5.5–23 mm; calyx cylindric or campanulate, (3.4–)3.8–12.5 mm, strigose, strigulose, or villosulous, tube 2.7–10 mm, lobes subulate or triangular, 0.5–5 mm; corolla pink-purple to purple, ochroleucous, yellowish, or whitish, sometimes veined, suffused, or tipped with lavender or pink; banner recurved 30–50°; keel 6–16.4 mm. Legumes readily deciduous from receptacle when mature, except vars. mokiacensis and trumbullensis where firmly attached and falling while still attached to pedicel, ascending or spreading and incurved, green, sometimes red- or purple-mottled, usually becoming stramineous or brownish, usually incurved, sometimes ± straight, usually ± ovoid, less often oblong, lanceoloid, or linear, usually strongly inflated or bladdery-inflated, rarely not or scarcely so, 8–40(–48) × (3–)4–18(–19) mm, usually bilocular, sometimes semibilocular, leathery, papery, or papery-membranous, usually glabrous, sometimes puberulent, strigose, strigulose, villosulous, or villous-tomentulose; usually inflexed as a complete septum, rarely incomplete, seed-bearing flange either conspicuous or subobsolete; usually sessile, rarely shortly stipitate. Seeds (7–)10–42.