Family: Brassicaceae, Mustard view all from this family
Description An erect, coarse-stemmed, biennial herb in the mustard family.
Habit: native perennial herb; multiple branched stems rises from an elongated woody caudex.
Height: 8-32 in (20-80 cm)
Leaf: at base, lanceolate to linear, minutely toothed, stalked, to 6 in (15 cm) long, to 0.5 in (1 cm) wide.
Flower: yellow to yellow-orange, 4 petals, on lateral stem at top of plant, 1-2 in (2.5-5 cm) wide.
Fruit: slender pod, to 4 in (10 cm) long, held upright close to the stem.
March to July.
Endangered Status The Contra Costa Wallflower, sometimes considered a subspecies of the Western Wallflower, is on the U.S. Endangered Species List. It is classified as endangered in California. The Antioch Sand Dunes are home to the Contra Costa Wallflower. The dunes are a unique environment hosting many plants more commonly found in deserts to the south. The Antioch dune complex is the largest of several such habitats, but it has been considerably reduced in size by sand mining and industrial development. The Antioch Sand Dunes National Wildlife Refuge has been established on 55 acres to protect all of the remaining populations of the Contra Costa Wallflower, in addition to other endangered species.
Habitat Sand dunes in the San Joaquin River delta.
Range Contra Costa County, California, east of Antioch; 10-66 ft (3-20 m).
Contra Costa wallflower is a federal endangered species. Antioch Dunes Refuge was established in 1980 to protect it and two other endangered plants. Located along the south shore of the San Joaquin River, the refuge was part of an expanse of 100-foot-high sand dunes formed along the river after the Mohave Desert receded in prehistoric times. Isolation of this sand dune habitat resulted in the development of subspecies of plants and insects that are found nowhere else in the world.