howellii is a short-lived perennial plant with thick stems varying from 4 to 40 inches in length.

The grayish colored leaves are shaped like a lance and are about 1 to 5 inches long with many hairs, primarily short with only a few being longer.

[4] The flowers are a major host plant for a rare species of sweat bee, Sphecodogastra antiochensis.

howellii, the Antioch Dunes Evening Primrose, was declared an endangered species.

The refuge was formed in 1980 to prevent extinction of this plant, as well as Lange's metalmark butterfly (Apodemia mormo langei) and the Contra Costa wallflower (Erysimum capitatum var.