aka Sand-dwelling Wallflower. Relatively large flowers, up to 5/8″ broad (1.5 cm), form a brillant yellow sphere atop a stem reaching to 16″ (40 cm). Small leaves grow on the entire length of stem while larger ones forming a basal rosette (see detail). It is thought that acrid mustard juices when applied as a poultice would draw out the cause of pain, thus the name. Usually found on rocky slopes at between 5,000′ to 7,000′ elevation.