Arabidopsis halleri

Arabidopsis halleri is a small perennial herb of the mustard family Brassicaceae, native to central and southern Europe and parts of temperate east Asia where it grows on rocky slopes, stream banks and notably on metal-contaminated soils. The species is well known to plant biologists as a hyperaccumulator of zinc and cadmium and a close relative of the model plant Arabidopsis thaliana. Plants spread by short stolons to form small loose mats of basal rosettes. The basal leaves are obovate to spatulate, 1 to 4 centimetres long, with shallowly toothed to pinnately lobed margins and a thin texture. Flowering stems are slender, 10 to 30 centimetres tall, bearing a few smaller stem leaves and a terminal raceme of small white four-petalled flowers about 6 to 10 millimetres across. Fruits are slender erect siliques 1 to 3 centimetres long containing numerous tiny seeds. Several subspecies have been described.