Rare Plant Ranking & Review

Monolopia congdonii. Credit David Magney.

Continuous data analysis and dissemination

For more than 50 years, CNPS has been leading efforts to review and rank the rarity of California’s native plants. This is an iterative and scientifically vetted process made possible through a community of scientists and volunteers working throughout the state and nation, and in working closely with the California Natural Diversity Database (CNDDB) of the California Department of Fish and Wildlife. This important data builds a foundation for the ongoing stewardship, appreciation, and conservation of California’s rare and endangered plants.

Major changes to the CNPS Inventory of Rare and Endangered Plants (i.e. additions, deletions, and changes to California Rare Plant Ranks) are reviewed by CNPS, the CNDDB, regional Plant Status Review Groups, members of the Rare Plant Status Review Forum, and other experts. Once consensus is reached, additions and changes are made to the CNPS Inventory and CNDDB, and the associated Rare Plant Status Review Forum post is closed for further comment (view the Rare Plant Status Review process flowchart and Cooperative Relationship between the CNDDB and CNPS for more details).

(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 rank changes), we ask that requesters formally “sponsor” proposed changes by using our 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 Groups and Forum

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 and 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 online Rare Plant Status Reviewer Form.

If you feel you might qualify as a reviewer, but are not able to fill out and/or submit this form, please contact the CNPS Rare Plant Program at rareplants@cnps.org for more information on how to get involved.

Regional Plant Status Review Groups

The plant status review groups are email groups divided into seven regions throughout the state following the Jepson eFlora geographic subdivisions. Status review proposals are sent to each regional email group that the plant under review is known to geographically occur in. For example, if a plant undergoing status review occurs in the Western Transverse and inner South Coast ranges, the status review proposal will be sent to both the Central West and South West status review email groups. If you wish to be involved in a regional review group, please fill out and submit our online Rare Plant Status Reviewer Form.

  • 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