Description: Annual, biennial or perennial herbs, usually glabrous, some aquatic.
Leaves simple to pinnate.
Flowers in racemes. Sepals dimorphic, inner pair saccate. Stamens usually 6, sometimes 4. Stigma 2-lobed to capitate.
Siliqua generally linear, beakless; valves convex, the midvein ± inconspicuous; seeds usually in 2 rows per loculus, sometimes mucilaginous when wet, testa reticulate or spongy.
Distribution and occurrence: World: 70 species, cosmopolitan. Australia: 7 species (4 species endemic, 3 species naturalized), all States.
The genus Nasturtium has sometimes been included in Rorippa (see note on Nasturtium pages for details). The key below includes species of Nasturtium which were, until recently, included in Rorippa in NSW Flora Online. K.L.Gibbons, 21 Feb. 2020.
Text by L. Retter & G.J. Harden, Flora of New South Wales Vol. 1: 478-480 (1990)
Taxon concept: Australian Plant Census (accessed May 2017)
| | Key to the species | |
| 1 | Petals yellow; siliqua more or less inflated, less than 10 mm long | Rorippa palustris |
| Petals white; siliqua not inflated, more than 10 mm long | 2 |
| 2 | Plants stoloniferous, aquatic to semiaquatic | 3 |
| Plants with a taproot, not aquatic, though sometimes growing in damp sites
Back to 1 | 4 |
| 3 | Seeds in 1 row per loculus, testa with c. 100 depressions per face; siliqua 15–30 mm long | Nasturtium microphyllum |
| Seeds in 2 rows per loculus, testa with 25–50 depressions per face; siliqua 10–18 mm long
Back to 2 | Nasturtium officinale |
| 4 | All or at least lower leaves not lobed, margins entire or toothed | Rorippa gigantea |
| At least lower leaves deeply lobed, pinnatifid or pinnatisect
Back to 2 | 5 |
| 5 | Stamens 6; testa reticulate or tuberculate | Rorippa dictyosperma |
| Stamens 4; testa spongy
Back to 4 | 6 |
| 6 | Seeds rounded, in 2 rows, less than 0.75 mm long | Rorippa eustylis |
| Seeds slightly winged, in 1 row, more than 0.75 mm long
Back to 5 | Rorippa laciniata |
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