The City of Boulder Open Space & Mountain Parks herbarium (CIBO) contains over 2800 specimens representing over 900 unique taxa as of 2018. The collection documents the plains and foothills flora in over 45,000 acres of City of Boulder protected land that spans the Great Plains and Southern Rocky Mountain ecotone in this part of the Colorado Front Range. In 1987, volunteers Elaine Smith and Jeannine Shawver worked with Open Space staff to establish the herbarium with the goal of creating a complete collection of the vascular plants present on City of Boulder Open Space lands. To date, we estimate that we have collected over 85% of the vascular species recorded on our lands. The herbarium has expanded significantly since its founding, with incorporation of historic specimens dating back to 1983, periodic inventories by professional botanists, and the dedication, expertise and persistent work of volunteers over the last 30 years. In 1999, Professor William A. Weber (University of Colorado Herbarium) reviewed and annotated over one third of the collection. In 2018, the entire collection was imaged and georeferenced by the University of Colorado Herbarium. Today the collection represents diverse habitats that include wet meadows, upland prairies, shrublands, riparian corridors, canyons, ponderosa pine and mixed forests at elevations ranging from 5,000 to 10,100 feet.