Differs from Nasturtium R.Br. primarily by its small yellow flowers with short or reduced petals, erect habit and usually with a ± slender tap root.

Annual to perennial herbs of damp places, usually with a slender tap root or rootstock. Leaves pinnate to almost entire. Petals often about as long as the sepals, rarely absent. Stamens 6, rarely 4 (the outer pair abortive). Ovary oblong to suborbicular, many ovuled. Siliquae linear-cylindrical, ellipsoid or almost spherical, bilocular, dehiscent; valves convex, membranous, usually glabrous; septum membranous; seeds mostly biseriate, suborbicular, reddish-brown, with finely reticulated surface; radicle accumbent.