Annual herbs with simple and forked hairs. Basal leaves petiolate or subsessile, entire or toothed, often withered at anthesis; cauline leaves sessile, sagittate or auriculate, simple or toothed. Inflorescence a raceme. Sepals erect, equal; petals clawed, usually yellow, apex obtuse; stamens 6. Fruit ± obovoid, less than 3 times as long as broad, dehiscent; style persistent, up to 4 mm long, capitate; valves convex, margins flattened, often with a prominent midvein; seeds in 2 rows per locule, mucous.
6 or 7 species from Europe and asia; 2 species naturalised in Australia.