| 1 | Racemes bracteate |
| 1' | Racemes ebracteate (rarely with a few bracts at the lowest pedicels). |
| 2 | Siliquae not more than 1.5 mm thick |
| 2' | Siliquae more than 1.5 mm thick. |
| 3 | Pedicels of fruits straight. |
| 3' | Most pedicels of fruits curved. |
| 4 | Seeds not over 0.8 mm long |
| 4' | Seeds longer than 0.8 mm. |
| 5 | Cauline leaves numerous; seeds distinctly reticulate (c. 150 areoles per face) |
| 5' | Cauline leaves absent or few; seeds very finely reticulate (over 300 areoles per face) |
| 6 | Petals white. Seeds coarsely reticulate |
| 6' | Petals yellow. Seeds with very fine surface patterns. |
| 7 | Ripe siliquae inflated, semiglobose |
| 7' | Ripe siliquae ± ellipsoid to sausage-shaped, not inflated. |
| 8 | Seeds with warty processes. Very tall and stout plants |
| 8' | Seeds without processes. Moderately high plants |
