Abstract
The North American Great Basin is a region known for its unique geology and harsh climate. Several plant species are endemic to the Basin, including three that were under consideration for endangered species listing by the US Fish and Wildlife Service. During a 2012 inventory for these species, an undescribed Brassicaceae monospecific genus, Terraria, was discovered. Our study presents results from morphological and evolutionary investigations, as well as preliminary ecological observations, of the novelty. Sequence data from rbcL firmly placed the discovery in the tribe Thelypodieae The relationships and distinguishing characters of Terraria haydenii are presented.