| | 1. "Leaf" segment margins and winter-bud scales, if present, lacking bristles ("leaf" segments of U. minor may be bristle-tipped); corolla < 9 mm |
| |
| | 2. "Leaf" generally 2-parted at base, each part forked again or not; ultimate segments < 6, thread-like; pedicel erect in fruit; corolla lower lip ± = upper, spur conic, less wide than long; seed winged |
| U. gibba |
| | 2' "Leaf" generally 3-parted at base, each part forked 1–3 times; ultimate segments > 6, flat; pedicel recurved in fruit; corolla lower lip ± 2 × upper, spur sac-like, as wide as long; seed wingless |
| U. minor |
| | 1' "Leaf" segment margins and winter-bud scales with fine, non-green bristles; corolla > 9 mm |
| |
| | 3. "Leaf" 3-parted at base, each part unequally 1–3-forked; ultimate segments < 20, linear, flat; bladders borne on leafless stems; pedicel erect in fruit; corolla lower lip ± 2 × upper |
| U. intermedia |
| | 3' "Leaf" 1–2-parted at base, each part several times ± pinnately branched; ultimate segments > 20, thread-like; bladders borne on "leaves"; pedicel recurved in fruit; corolla lower lip ± = upper |
| U. vulgaris
|