Herbaceous biennial or perennial, reaching 90 cm in height, with dense whitishgrey tomentum. Upright ramose stem, woody at the base. Lanceolate, acute, generally entire leaves, 5-25 x 0.7-5 cm, with the basal leaves borne in a rosette. Flowers with violet or purplish-violet or more rarely, white petals, 18-28 x (6-)8-12 mm, borne in a racemose inflorescence. Almost cylindrical, flattened, uprightspreading fruits (siliquas), (50-)80-150 x 3-4.5 mm.
Common species which inhabits rocky slopes and arid soils on the coast of Madeira, Porto Santo and Desertas, mainly at altitudes of 0-100 m and some peaks on Porto Santo.