Rare Plant Ranking & Review

Monolopia congdonii. Credit David Magney.

Continuous data analysis and dissemination

For more than 35 years, CNPS has been leading efforts to review and rank the rarity of California’s rare plants. This is an iterative and scientifically-vetted process made possible through a community of scientists and volunteers working throughout the state. This important data builds a foundation for the ongoing stewardship, appreciation, and conservation of California’s rare and endangered plant species.

Major changes to the Inventory (i.e. additions, deletions, CNPS list changes, scientific name changes) are reviewed by CNPS, California Natural Diversity Database (CNDDB), regional Plant Status Review groups, and other experts. Once consensus is reached about a change, it is added to a group of pending changes, which are implemented on a quarterly basis (view the Rare Plant Status Review process flowchart for more detail).

(For the process of reviewing rare lichens, please see Sponsoring Lichens of Conservation Concern.)

How to recommend a change or addition to the Inventory

In order to expedite the review and processing of major changes (additions, deletions, or list changes), we ask that requesters formally request or “sponsor” proposed changes by using our new sponsorship package. This procedure is more efficient because it specifies the type of data we need, organizes the information in a standard format, and makes it easier to identify data gaps. The sponsorship package requests supporting data and rationale for a proposed major change and consists of 4 documents, which can be downloaded using the links below:

Chlorogalum purpureum reductum. Credit David Magney.
Chlorogalum purpureum reductum. Credit David Magney.

Rare Plant Status Review Forum

Access here

Rare Plant Status Review Forum and Review Groups

Who can participate?

CNPS solicits information about proposed changes to the CNPS Inventory as part of its review process. The CNPS Rare Plant Program encourages anyone who has knowledge about native plants, particularly rare plants, to contribute their comments/data as a Rare Plant Status Reviewer via the Rare Plant Status Review Forum.

In order to join a Regional Plant Status Review Group and/or become a member of the Rare Plant Status Review Forum, please fill out and submit the Rare Plant Status Reviewer form to Aaron E. Sims (asims@cnps.org).

If you feel you might qualify as a reviewer, but are not able to fill out and/or submit this form, please contact Aaron E. Sims (asims@cnps.org) for more information on how to become involved.

How to join the forum

  1. Go to forum.cnps.org
  2. Click on the “Register” link on the top of the page.
  3. Fill in the fields on the registration form, choose your preferences and submit. Please choose a username that contains your name (e.g. joe smith, joesmith95814, etc.)
  4. After registering, email your Username and a filled out copy of the reviewer form to asims@cnps.org.
  5. Once you receive an email confirmation from Aaron, log in at the top of forum.cnps.org.
  6. Click on Rare Plant Status Review and select a taxon to review. Use the “Post Reply” button to share your comments/data.

Note: This discussion forum is only visible when you are logged in.

Please contact Aaron Sims at asims@cnps.org if you have any questions.

Regional Plant Status Review Groups

The plant status review groups are divided into seven regions of the state (following those in The Jepson Manual). If you wish to be involved in a regional review group, please send an email to asims@cnps.org with your name, affiliation, and the name of the region in which you wish to participate.

  • Central West (CW): Includes the central coast area of California, from Marin County in the north down through the south coast ranges, including much of Santa Barbara County in the south.
  • East Side / Deserts (ES/D): Includes the east side of the Sierra Nevada Mountains from Mono County south through all of the Mojave and Sonoran deserts.
  • Great Valley (GV): Includes all of the Sacramento and San Joaquin valleys.
  • Modoc Plateau (MP): Includes all of the Modoc Plateau area of California.
  • North West (NW): Includes all of northwestern California, from Sonoma and Napa counties in the south, north to the Oregon border, including the North Coast ranges, the Klamath Range, and the Cascades.
  • Sierra Nevada (SN): Includes the Sierra Nevada range from Plumas County in the north to the Tehachapis in the south.
  • South West (SW): Includes all of southwestern (non-desert) California, from coastal Santa Barbara County in the north to the Baja California border, including the Western Transverse and Peninsular ranges.

CNPS Rare Plant Ranks

See definitions for each plant rank level.

Learn More