Using the Rare Plant Inventory Advanced Search
Using the RPI's advanced search allows you to unlock even more capabilities! List/Rank, Location, Biology, and more.
Rare Plants
Fighting extinction, building understanding
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
Areas of Focus
Rare Plant Ranking & Review
Get details on the CNPS ranking categories and how plants are assigned each rank.
Locally Rare Plants
These species are critical to the preservation of regional genetic diversity. Here’s what you should know.
Rare Plant Treasure Hunts
Professionals and citizen scientists working to monitor and track our most vulnerable species.
Recent Stories
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How to Search the Rare Plant Inventory
Over one-third of California’s flora is considered rare. Learn expert tips to search the RPI to prepare a list of rare plant species for a project. -
The Many Uses of the CNPS Rare Plant Inventory
It sounds mysterious and magical, like an ancient tome you would check out of the library. Where does it come from?