Key to the Genera
| 1a | Plant acaulescent or caulescent; leaf blades of many species about as broad as long or broader, base cordate; peduncle not articulated; sepals with basal auricles; bottom petal spurred at base, blade distinctly shorter than lateral and upper petals | |
| Viola L. | ||
| 1b | Plant caulescent; leaf blades much longer than broad, base narrowly cuneate; peduncle/pedicel juncture articulated; sepals lacking basal auricles; bottom petal saccate at base, blade slightly to greatly exserted beyond lateral and upper petals | 2 |
| 2a (1) | Stem unbranched; leaves strictly alternate; leaf blades entire or with 1–2 random coarse teeth on either margin; corolla uniformly green; bottom petal < 1.3 × as long as others, blade slightly expanded, retuse; capsule 15–23 mm long; seeds 4.5–5.0 × 3.5–4.8 mm, subglobose, tan; native to e. North America | |
| Cubelium (T.F.Forst.) Raf. ex Britton & A.Br. | ||
| 2b | Stem branched from base or lower nodes; upper leaves alternate and lower (sub)opposite; leaf blades entire or uniformly crenate to serrate; corolla white to violet or blue with yellow throat; bottom petal 1.5–3 × as long as others, blade somewhat to very much expanded, emarginate to broadly rounded; capsule < 10 mm long; seeds < 2 mm broad, flattened, black; native to the Great Plains, sw. North America and Latin America, two species occurring as sporadic waifs near the Atlantic coast and s. FL | |
| Pombalia Vand. |