A perennial, herbaceous plant in the mustard family (Brassicaceae). It is approximately 5 to 15 centimeters (cm) (2 to 6 in.) tall and usually forms raised clumps or cushions (pulvinate growth form) up to 20 cm (8 in.) wide. The species arises from a deep woody taproot; its stems are smooth and hairless with narrow leaves clustering at the base of the plant. The species cream-colored flowers are about 5 to 7 millimeters (mm) (0.25 in.) across and alternate along a stem rising 2.5 to 6 cm (1 to 2.5 in.) above the base of the plant. The flowers begin to bloom in early May. Seeds are quite small, about 1 mm (0.04 in.) across, and are borne in elliptical seed pods called silicles, which are about 4 to 5 mm (0.2 in.) long. The seeds are shed beginning in June and continuing into July (Reveal 1967; Welsh and Reveal 1977; Welsh et al. 1987)