Scrophularia

1. Staminodium greenish or yellowish, the free apex usually distinctly broader than long; mature capsules (5–) 6–9 mm long; larger leaf blades truncate to rounded at base, never cordate.

S. lanceolata

1. Staminodium dark brown or purple (very rarely green), the free apex scarcely if at all broader than long; mature capsules 4–6 (–7) mm long; larger leaf blades often cordate.

S. marilandica