Rare Plants

Fighting extinction, building understanding

Cone of the yellow cedar. Credit Michael Kauffmann.

Since its inception in 1968, the CNPS Rare Plant Program has been a trusted resource for scientific accuracy and integrity. CNPS rare plant data are widely accepted as the standard for information on the rarity and endangerment status of the California flora. Today, we’re using these data to fight extinction, engage citizen scientists, and inform land use decisions statewide. Support CNPS plant science today!

Rare Plant Inventory

First published in 1974, the Inventory is a widely-accepted authoritative resource on California’s rare and endangered plants. Now in its 8th edition online, it continues to play an important role in scientific research, conservation planning, and the effective enforcement of environmental laws. Learn more about the Inventory or access it now.

CNPS Rare Plant Ranks

CRPR Definitions

Areas of Focus

Astragalus pycnostachyus lanosissimus. Credit David Magney.
Astragalus pycnostachyus lanosissimus. Credit David Magney.

Rare Plant Ranking & Review

Get details on the CNPS ranking categories and how plants are assigned each rank.

Mather vernal pool. Credit Greg Suba.
Mather vernal pool. Credit Greg Suba.

Locally Rare Plants

These species are critical to the preservation of regional genetic diversity. Here’s what you should know.

Vegetation workshop
Vegetation workshop

Rare Plant Treasure Hunts

Professionals and citizen scientists working to monitor and track our most vulnerable species.

Rare Plant Forums

Rare plant status review

Rare plant status review

Credit David Magney.

Phenology forum

Phenology forum

Credit David Magney

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