California Native Plant Society

The CNPS Inventory of Rare and Endangered Plants

The CNPS Inventory of Rare and Endangered Plants (The Inventory) has served as a resource for information about California's rare plants for over 35 years. The Inventory is a credible and widely-recognized resource that plays a significant role in promoting scientific research, conservation planning, and the effective enforcement of environmental laws that deal with plant conservation. The Inventory also helps to build a foundation for stewardship and conservation by celebrating the unique richness of, and facilitating education about California's rare plants. CNPS published the first edition of its Inventory of Rare and Endangered Plants in 1974. The Inventory was published in print form a total of 6 times (the last print version, the 6th Edition was published in 2001).

(Note, in 2014 the CNPS Rare Plant Program began including Lichens of Conservation Concern in the Inventory based on information provided by the California Lichen Society's Conservation Committee.)

The Online CNPS Inventory of Rare and Endangered Plants (8th Edition)

Visit the Online Rare Plants InventoryThe Online Inventory, 8th Edition was released in December of 2010. Our primary goal for this edition was to create a more intuitive end user experience while providing substantially improved functionality; thus making work with the vital data more enjoyable, easy, and fun.

The Online Inventory is used on a daily basis by conservationists, consultants, planners, researchers, and resource managers to obtain information about California's rare plants. This information is often used to help educate landowners and public policy makers about the importance of rare plant stewardship and conservation. Online Inventory data helps to provide decision makers with the information needed to identify, protect, and manage California's unique and fragile botanical resources. Individuals preparing environmental documents (for review under the California Environmental Quality Act (CEQA)) often use the Online Inventory to help determine the potential for resource conflicts, and to develop project-specific lists of rare plants to target during botanical surveys. Conservationists and resource managers use the same information to review environmental documents and prepare public testimony to influence decision makers. As a result, the Online Inventory directly guides rare plant protection efforts, conservation planning, and land acquisition and management.

The 8th Edition could not have been completed without a significant, large contribution from a private donor, a smaller CNPS Board allocation from funds donated by the late June Bilisoly, and a number of other contributions from users of the database. CNPS offers our sincere appreciation for these financial contributions, as well as the combined efforts of many other individuals who helped with the design, development, and implementation of the project.

More information:


The 7th Edition of the Online CNPS Inventory of Rare and Endangered Plants

CNPS Inventory data was first made available online in 2001 with the release of the Online Inventory of Rare and Endangered Plants (Online Inventory, 7th Edition). The 7th Edition of the Online Inventory is still fully functional and available to use by following the link below.

Online Inventory, 7th Edition


Editions 1 through 6 of the CNPS Inventory of Rare and Endangered Plants 

Click on a cover image below to download a full copy of the corresponding edition of the CNPS Inventory. While some of the data present in the past editions are out-of-date, there is still a lot of information that is extremely useful and valuable for those involved in rare plant conservation. All of the inventories have a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) license.

1st Edition Inventory cover
1st Edition (PDF 8.6MB)
2nd Edition Inventory cover
2nd Edition (PDF 8.9MB)
2nd Edition Inventory, supplement 1 cover
2nd Edition, Supplement 1 (PDF 2.7MB)
2nd Edition Inventory, supplement 2 cover
2nd Edition, Supplement 2 (PDF 4.9MB)
3rd Edition Inventory cover
3rd Edition (PDF 18.8MB)
4th Edition Inventory cover
4th Edition (PDF 17.2MB)
5th Edition Inventory cover
5th Edition (PDF 47.2MB)
6th Edition Inventory cover
6th Edition (PDF 30MB) (introductory material HTML)


Interpreting lists in past editions in relation to current California Rare Plant Ranks (CRPR):

  • 1st Edition:
    Very Rare and Rare and Endangered Plants (pp. 12-32), mostly represents what is currently considered CRPR 1A and 1B.
    Appendix I, Rare and Not Endangered Plants (Including Some of Uncertain Status) (pp. 33-40), mostly represents what is currently considered CRPR 2B.
    Appendix II, Plants Not Rare But Mostly of Limited Distribution (pp. 41-42), mostly represents what is currently considered CRPR 4.
  • 2nd Edition:
    List 1- Plants Presumed Extinct, represents what is currently considered CRPR 1A.
    List 2- Plants Rare and Endangered, represents what is currently considered CRPR 1B.
    List 3- Plants Rare, But Not Endangered, represents what is currently considered CRPR 4.
    List 4- Plants Rare in California, Common Elsewhere, represents what is currently considered CRPR 2B.
  • 3rd to 6th Editions:
    Lists correspond to current CRPRs.


Updates to the CNPS Inventory, 6th Edition

Silene serpentinicola
Silene serpentinicola was added to the CNPS Inventory (List 1B.2) in 2005. Photo by S. Carothers.

For those who still have and use the 6th edition CNPS Inventory, you can see major changes that have been made to the Inventory since 2001 by viewing this PDF document (29kb PDF). This document lists the species that have been added to the Inventory, have had their listing status changed in the Inventory, have been deleted from the Inventory, and have had their name changed in the Inventory since the publication of the 6th edition CNPS Inventory in 2001. For the most up-to-date information on rare plant species in California, please visit the CNPS Online Inventory.

Questions or Comments?

Please contact the CNPS Rare Plant Botanist Aaron Sims at 916/324-3816 or via email at To purchase a copy of the 6th edition Inventory, visit our online bookstore or contact CNPS at 916/ 447-2677.


Taxa not Included in the 6th Edition

CNPS has tracked plants that are rare from a statewide perspective since the late 1960's with over 2,000 taxa currently considered by CNPS to be rare statewide (see CNPS' Online Inventory of Rare and Endangered Plants of California). However, one should keep in mind that if a species is not included in the CNPS Inventory, it does not necessarily mean that the species is not rare.

While CNPS strives to maintain an accurate and up-to-date list of rare plants, the size of California, the large number of unique California endemic plants, and the dynamic nature of rare plant data makes maintaining this list a challenging enterprise. There are several major reasons why a plant not included in the CNPS Inventory may still be considered rare. One should consider the issues below before making a final decision on the rarity of a plant.

  • Many plants that are not rare from a statewide perspective may none-the-less be rare from a regional perspective (see Locally Rare Plants discussion).
  • Species that were once considered to be too common or that were not thought to occur in California ('considered but rejected' taxa), may have become rare or have subsequently been found in California in the years since the taxon was first examined by CNPS and the information has not yet been updated. See below for a list of Considered But Rejected Taxa (CBR).
  • Species that are on the list of postponed taxa may in fact be rare and would especially benefit from collection of information so that an accurate assessment of their rarity can be made. See below for a list of Postponed Taxa.
  • There are also taxa that have not yet been brought to the attention of CNPS as rare or that are in the CNPS backlog of rare taxa scheduled to undergo review for inclusion in the CNPS Inventory. If you know of a plant that should be considered for inclusion in the CNPS Inventory, please submit a sponsorship form located at the bottom of this page.

A list of taxa that have been considered by CNPS but subsequently rejected for inclusion in the Inventory, as well as a list of species that have been postponed, are provided below. If you have information that any of these taxa deserve inclusion in the CNPS Inventory, please let us know by contacting CNPS Rare Plant Botanist Aaron Sims at 916/324-3816 or

Considered But Rejected (CBR) Taxa - contains a list of taxa that have been considered for inclusion into the CNPS Inventory, but were not included for various reasons.

Postponed Taxa (PDF, 17k) - contains a list of approximately 300 taxa, which were considered as possible new additions during the development of the CNPS Inventory 6th edition and our ongoing data review process, but were "postponed" due to significant taxonomic uncertainty and/or lack of information regarding distribution, abundance, rarity and/or endangerment.


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