Erysimum teretifolium is a species of wallflower known by the common names Santa Cruz wallflower and Ben Lomond wallflower. It is a very rare plant endemic to Santa Cruz County, California, where it grows on inland sand spits, chaparral, and sandstone deposits in the southern Santa Cruz Mountains. It is a California state and federally listed endangered species. This plant is a biennial or perennial herb with one or more unbranched erect dark reddish-purple stems reaching anywhere from 15 centimeters to nearly a meter in height. There are a few straight, somewhat toothed, dark greenish leaves along the stems. At the tops of the stems are thin clusters of flowers with rounded bright to dark yellow or orangish petals, each one or two centimeters long. The flowers drop to leave long, flat fruits which are siliques up to 15 centimeters long, sticking out from the stem.