This native plant is a biennial that consists of a rosette of basal leaves during the first year. The basal leaves are up to 6' long and 2' across; they are oblanceolate or obovate, dentate along the margins, and hairy underneath. Each basal leaf tapers to a petiole-like base that is long and slender, while its tip is acute to blunt. During the second year, one or more stems with alternate cauline leaves develop from the center of the rosette, which withers away. Upon reaching maturity, Toothed Rock Cress is 1½–3' tall. The erect to ascending stems are light green, finely pubescent, terete, and sparingly branched. The cauline leaves are up to 4' long and 1½' across; they are oblanceolate to obovate and dentate along their margins. The upper surface of each cauline leaf is sparingly covered with fine hairs or hairless, while the lower surface is conspicuously hairy. Each cauline leaf clasps the stem with a pair of basal lobes (it is auriculate). The upper stems terminate in floral racemes up to 1' long. Each flower is about 1/8' across, consisting of 4 sepals, 4 petals, an ovary with a short style, and several stamens with pale yellow or white anthers. The petals are white and oblanceolate; they barely extend beyond the sepals. The sepals are lanceolate-oblong, light green to reddish green, and finely hairy. The pedicel of each flower is short, stout, and conspicuously hairy. The blooming period occurs during the late spring or early summer and lasts about a month. Each flower is replaced by a slender cylindrical silique about ¾–1½' long that contains a single row of seeds. The siliques are ascending to spreading along the central stalk of the raceme; they can be curved or straight, but don't droop conspicuously. The outer surface of each silique is light green to reddish purple and glabrous or finely pubescent (usually the latter). The seeds are quite small (about 1 mm. long), oblongoid, and somewhat flattened; they lack winged margins. The root system consists of a taproot. This plant spreads by reseeding itself.