Plants of the World Online recognises 263 species in the Peppercress genus.
Found worldwide, Australia has around 7 naturalised species and 35 endemic or native with around 8 occurring in S. E. Queensland.

Most are annual to perennial herbs with erect stems 50 to 60 cm high with a few up to 80 cm.
There are also some small shrubs and others with prostrate stems.
A few can scramble over other vegetation with stems up to 2 m long.
They grow from a taproot and parts can be smooth or have long or short simple hairs with a sharp or blunt tip.

Leaves are very variable and a plant can have similar leaves throughout or different ones at the base and top with a sudden
    or gradual change between them.
Basal and lower stem leaves can be up to around 10 cm long by 4 cm wide and on a petiole.
Upper stem leaves can be a few mms long and wide.
Stem leaves, especially the upper may have no petiole at all and the blade base may have lobes that sheath the stem.

The blade outline can be linear, elliptic, lanceolate, oblanceolate, ovate, obovate to almost circular.
The edge can be entire but is typically dissected or at least lobed to some extent especially on the basal and lower stem leaves.
These can be pinnatisect or pinnatifid with lobes half to all the way to the midrib respectively.
Some are divided 2 or 3 times and there may be teeth on the edge and fine hairs.

Short to long terminal or axillary inflorescences are typically a raceme with flowers, on a pedicel along a central
    midrib with the lower ones opening first.
Most continue to lengthen as the fruit matures at the base and new flowers open at the tip.
Flowers have 4 elliptic green sepals, often with a reddish edge, that are longer or shorter than the petals.
There are usually 4 white petals up to 5 mm long but occasionally there are none.

Flowers can have 6 stamens or 2 or 4.
When 4 or 6 they may be in 1 or 2 whorls with the inner ones being longer.
There are often 4 or 6 nectary glands beside the stamen filaments.
The superior ovary, of 2 fused carpels has 1 locule divided by a false septum.
Flattened front to back the ovary has 2 ovules.
There is a very short or no style and a capitate (head-like) or slightly bi-lobed stigma.

The flattened round to elliptic fruit capsules (silicula) are 2 to 6 mm long.
The style is in a shallow to deep notch at the round or pointed tip.
Each side (valve) can have a sharp keel or a wing part or all the way down.
The 2 flattish reddish-brown seeds may have a narrow wing.