Annual to perennial herbs, sometimes woody below, often much branched, glabrous or hairy with usually simple hairs; branches often apparently dichoto¬mous. Leaves usually linear or elliptic, entire, toothed or pinnatifid; lower often stalked; upper sessile or sub-sessile. Racemes corymbose, ebracteate, often dense. Flowers small, white, rarely yellowish or pinkish, pedicellate. Sepals 4, short, subequal, oblong, obtuse, glabrous, often green with white margin; inner slightly broad but not saccate at the base. Petals 4, small, linear to spathulate, sometimes shorter than the sepals, rarely absent or rudimentary. Stamens 6, or by abortion 4 or 2; filaments simple; anthers short, ovoid or suborbicular, obtuse. Nectar glands usually fragmentary, minute, present between the stamen bases. Ovary flat, elliptic with generally two pendulous ovules; style short or absent; stigma capitate, often subretuse, usually subsessile or sessile in fruit. Siliculae ovate, obovate, orbicular or broadly elliptic, apex often ± notched, laterally flattened, dehiscent (rarely subdehiscent), bilocular; valves usually strongly keeled, often slightly winged towards the apex; septum narrowly elliptic, membranous, not veined; seeds generally one in each locule, ± ovate (often oblique), brown; radicle incumbent or obliquely so.
About 150 species of nearly cosmopolitan distribution; only 9 species known from our area.