Annual or biennial herbs (in ours). Flowers yellow in ebracteate racemes. Sepals erect, inner pair saccate. Petals 4, contracted at base into a claw. Stamens 6. Fruit a beaked siliqua with 2 valves, each valve with 1 prominent vein; beak with 0-3 seeds. Seeds in 1 series, ± spherical.