Thale Cress is a slender, erect plant that reaches 35cm in height, rarely more. It grows from a basal rosette of narrow, usually unlobed, elliptical leaves with short stalks, This rosette forms in the late autumn, survives the winter and dies when the plant begins to flower. There can be several flowering stems, and each of these can be branched with some lanceolate, stalkless leaves. The flowers are in racemes at the ends of the stems. They have short stalks. Each flower has four white petals measuring approximately 3 mm in diameter. The fruit pods are long, thin and curved slightly upwards, measuring 10-18 mm in length by 0.8mm in diameter.
Similar species: Other small annual species in the cabbage family (Brassicaceae) include Shepherd'spurse and Shepherd's Cress. These can be distinguished from Thale Cress by their flattened triangular- or spoon-shaped fruit capsules respectively. Flixweed is normally a much taller plant with small, yellow flowers and pinnate stem leaves.
Thale Cress is frequently associated with uncommon species of sandy soils, particularly in Breckland.Arable field margins, horticultural land, walls, waste ground, tracks. Well-drained sandy soils and sandy loams, frequently noncalcareous.