Caulanthus amplexicaulis is a species of flowering plant in the mustard family known by the common name claspingleaf wild cabbage. It is endemic to California, where it grows on open slopes in the Transverse Ranges and Outer South California Coast Ranges. Caulanthus amplexicaulis is annual herb produces a slender erect stem with flat, oval leaves clasping it toward the base. The bulbous purple flower forms a rounded pouch which opens at the top, the narrow petal tips reflexed back. The outer petal tips are deep purple, the inner much lighter to nearly white. The fruit is a very long silique which may exceed 10 centimeters in length. Varieties: There are two varieties of this species. Caulanthus amplexicaulis var. barbarae - Santa Barbara jewelflower; endemic to the serpentine soils of the San Rafael Mountains in central Santa Barbara County. The sepals forming the rounded pouch of the flower are white to cream in color as opposed to the bright purple of the more common variety. Caulanthus amplexicaulis var. amplexicaulis - endemic to the Transverse Ranges.