Northern Prairie Wildlife Research Center
| Lead | Characteristic | Go To |
| 1 | Flowers white or pink. | Lead 2 |
| 1 | Flowers yellow or yellowish-green. | Lead 4 |
| 2 | Plants stoutly taprooted; siliques distinctly stipitate, borne on a stipe that extends about 1 mm or more beyond the tip of the pedicel. | Genus Thelypodium |
| 2 | Plants fibrous-rooted, sometimes bulbous at the base as well; siliques sessile on the pedicels. | Lead 3 |
| 3 | Seeds in 1 row in each cell of the silique; plants of wet habitats but not usually growing in water. | Genus Cardamine |
| 3 | Seeds in 2 rows in each cell of the silique; plants usually growing in water. | Genus Nasturtium |
| 4 | Siliques linear or curved-linear, 20-30X or more longer than wide; seeds in 1 row in each cell of the silique. | Genus Barbarea |
| 4 | Siliques linear-elongate or cylindrical to globose, 1-8(10)X longer than wide; seeds in 2 rows in each cell of the silique. | Genus Rorippa |