Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for the Plant Thlaspi californicum (Kneeland Prairie Penny-Cress) From Coastal Northern California

We, the U.S. Fish and Wildlife Service (Service), determine endangered status pursuant to the Endangered Species Act of 1973, as amended (Act), for Thlaspi californicum (Kneeland Prairie penny-cress). Thlaspi californicum is known only from Kneeland Prairie in Humboldt County, California, where it grows in coastal prairie on serpentine outcrops. We consider the occurrences of T. californicum reported from Mendocino County to be T. montanum, a widely distributed species. Habitat loss, potential road realignment, and proposed airport expansion activities imperil the continued existence of T. californicum. The restricted range of this species, limited to a single population, increases the risk of extinction from naturally occurring events such as fire. This action implements the protection of the Act for this plant species.