The Colorado Rare Plant Field Guide was produced over a three year period through a cooperative effort involving many individuals and organizations.

The Bureau of Land Management, U.S. Forest Service, U.S. Fish and Wildlife Service, the Colorado Natural Heritage Program and The Nature Conservancy provided funds to produce the Colorado Rare Plant Field Guide. Funds for publication of the guide were provided by the U.S. Forest Service; the Denver Botanic Gardens; the Natural Resources Conservation Service; The Nature Conservancy; and the Colorado Natural History Small Grants Program, made possible by the Colorado Natural Areas Program and the Great Outdoors Colorado Trust Fund. Additional sponsors are listed on the following page. Sheri Morris and Tamera Hammack with the Bureau of Land Management in Cheyenne, Wyoming provided technical assistance in the prepress production of this document.

Data gathered from herbaria in Colorado, Wyoming, Utah, Nebraska, and Oklahoma were essential to the generation of accurate species accounts. We thank William Weber, Thomas Ranker, and Timothy Hogan with the University of Colorado Herbarium; Ronald Hartman and Ernie Nelson with the Rocky Mountain Herbarium; David Steingraber with the Colorado State University Herbarium; Hobart Dixon with the Adams State College Herbarium; Sylvia Kelso with the Colorado College Herbarium; Walter Kelley with the Mesa State College Herbarium; William Harmon with the University of Northern Colorado Herbarium; Neal Osborn with the University of Southern Colorado Herbarium; David Jamieson with the Fort Lewis College Herbarium; Stanley Welsh, Kaye Thorne, and Duane Atwood with the Brigham Young University Herbarium; Mary Barkworth and Linda Allen with the Intermountain Herbarium at Utah State University; Michael Windham and Ann Kelsey with the Garrett Herbarium at the University of Utah; Margaret Bolick with the CE Bessey Herbarium at the University of Nebraska; Janet Wingate with the Kathryn Kalmbach Herbarium at the Denver Botanic Gardens; Ronald Tyrl with the Oklahoma State University Herbarium; Paula Lehr with the Rocky Mountain Biological Lab.

We appreciate the input of our technical reviewers including Betsy Neely, Walter Kelley, Janet Wingate, Tom Ranker, Gwen Kittel, John Sanderson, Julie Burt, Craig Freeman, Ronald Hartman, Walter Fertig and Peter Root.

One of the great strengths of the guide is the depth of information provided through the technical illustrations and photographs. Individual artists and photographers are recognized throughout the text.

Illustrations of Astragalus brandegei, A. detritalis, A. duchesnensis, A. musiniensis, A. nelsonianus, A. piscator, A. rafaelensis, and A. sesquiflorus were reprinted with permission from Intermountain Flora, volume 3B, copyright 1989, The New York Botanical Garden. Illustrations of Cryptantha caespitosa, C. elata, C. mensana, C. osterhoutii, and C. rollinsii were reprinted with permission from Intermountain Flora, volume 4, copyright 1984, The New York Botanical Garden. The illustration of Aster horridus was reprinted with permission from A Handbook of Rare and Endemic Plants of New Mexico by the New Mexico Native Plants Protection Advisory Committee, copyright 1984, UMI Books on Demand. Illustrations of Cypripedium fasiculatum and Erigeron lanatus were reprinted with permission from Vascular Plants of the Pacific Northwest, parts 1 and 5, copyright 1969, University of Washington Press. Illustration of Salix myrtillifolia was reprinted with permission, copyright Jack Carter.

We are grateful for the many hours of hard work contributed by the Colorado Natural Heritage Program staff including Chris Pague, Katie Pague, Steve Kettler, Nancy Lederer, Diane Bacher, Vicki Frey, Renée Rondeau, Laura Carsten, Kim Fayette, Amy Holcombe, Maryanne Dornfeld, Julie Burt, Sara Gilbert, Denise Culver, Celine Donofrio, Jill Handwerk and Daryl Burkhard.

We thank all of the members of the Colorado Rare Plant Technical Committee, especially Lucy Jordan who started the Committee and brought forward the idea of a Colorado Rare Plant Field Guide.

Finally, the authors of the Colorado Rare Plant Field Guide would like to acknowledge the following organizations for their commitment to rare flora research and conservation. Their contributions towards printing costs helped ensure that copies of this Field Guide could be found in any office, field vehicle, classroom, or library.