Founded in 1959, the Portland State University Herbarium (HPSU) currently contains about 29,000 specimens of vascular plants, mosses, and lichens, and is the second-largest herbarium in Oregon. It consists of a core of 3,600 historical specimens collected between 1862 and 1920, with the remainder collected since 1959 by PSU faculty, students, agency botanists, consultants, and private individuals. The Herbarium is a regional resource focused on the changing flora of the rapidly urbanizing Portland-Vancouver metro area, the Columbia River Gorge, and the lower Columbia River region. Specimen data from the PSU Herbarium is available on the Consortium of Pacific Northwest Herbaria website, one of 11 portals that provide specimen label data, distribution maps, and images of more than 16 million specimens from the United States and Canada. The herbarium is part of the Portland State University Museum of Natural History.