1. Leaflets mostly 4–12 (in depauperate plants, some leaves with only 2 leaflets); native species.
2. Stipules (at least the larger ones, on upper part of plant) (7–) 10–20 (–25) mm broad; larger leaflets (1.2–) 1.5–3 (–3.5) cm wide; stems angled but not winged.
3. Flowers (except in rare albinos) purple to blue (or pinkish); stipules with 2 basal lobes (± hastate); sandy shores, beaches, and dunes.
3. Flowers cream; stipules with 1 basal lobe (semi-sagittate or semi-cordate); thickets and forests.
2. Stipules all less than 7 mm broad (very rarely broader, usually on plants with winged stems); larger leaflets 0.4–2.4 cm wide; stems winged or not.
4. Calyx glabrous or sparsely pubescent; principal leaves with 4–6 (–10) leaflets; racemes 2–8-flowered; stems often narrowly winged.
4. Calyx (and usually to some extent other parts) ± densely pubescent; principal leaves with 8–12 (–14) leaflets; racemes 6–26-flowered; stem not winged.
1. Leaflets 2; plants escaped from cultivation, usually near settlements or along roadsides.
5. Stems not winged (at most angled); flowers ca. 11–19 mm long.
6. Stipules (at least on main stem) with 2 basal lobes (hastate or sagittate); flowers bright yellow; leaflets narrowly acute at the tip.
6. Stipules with 1 basal lobe (semi-sagittate); flowers rose-red; leaflets broadly acute to rounded at the tip (except for excurrent midvein).
5. Stems distinctly winged with strips of green leaf-like tissue; flowers of various size.
7. Ovary and fruit pubescent with pustular-based hairs; annual.
8. Flowers less than 1.5 cm long; leaflets linear-lanceolate.
8. Flowers over 2 cm long; leaflets elliptic.
7. Ovary and fruit glabrous; perennials.
9. Main lobe of stipules more than half as wide as the winged stem; flowers ca. 16–26 mm long.
9. Main lobe of stipules up to half as wide as the winged stem; flowers ca. 12–18 mm long.