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.

L. japonicus

3. Flowers cream; stipules with 1 basal lobe (semi-sagittate or semi-cordate); thickets and forests.

L. ochroleucus

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.

L. palustris

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.

L. venosus

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.

L. pratensis

6. Stipules with 1 basal lobe (semi-sagittate); flowers rose-red; leaflets broadly acute to rounded at the tip (except for excurrent midvein).

L. tuberosus

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.

L. hirsutus

8. Flowers over 2 cm long; leaflets elliptic.

L. odoratus

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.

L. latifolius

9. Main lobe of stipules up to half as wide as the winged stem; flowers ca. 12-18 mm long.

L. sylvestris