The Kathryn Kalmbach Herbarium (KHD), a collection of over 75,000 vascular plant specimens, is a regional herbarium with a research focus on the species diversity of Colorado and the Southern Rocky Mountain region. The collection also contains species that are in cultivation at Denver Botanic Gardens. Most of the specimens within the collection have been digitized, and their photographs may be found online. Higher resolution images are also available upon request. Specimens collected in 2017 and later are likely to have an associated tissue sample available on GGBN.