Rare Plant Priorities
Protecting California’s Rare Plants.
California is a biodiversity hotspot with over 1,000 rare plants that are found nowhere else on Earth. These plants have novel evolutionary and ecological histories, and each species represents a unique branch on the tree of life. Extinction erases the genetic and ecological stories that these plants preserve, depriving future generations from knowing and experiencing an important part of our shared natural heritage.
CNPS works to protect rare and endangered species through a number of key initiatives:
We rank California’s rare plants and identify candidates for endangered species protection.
Our Rare Plant Committee drafts state and federal listing petitions. See recent victories.
Mapping priority plant conservation areas ahead of major development projects like the Delta Tunnels and high-speed rail.
Chapters identify local endangered species and drive regional conservation priorities.
We make seed collections stored across the state to safeguard the genetics and natural history of our unique flora.
CNPS is actively collecting data in recently burned areas across the state, collecting critical data about how these landscapes are recovering, tracking the response and status of rare plant populations, and providing timely data about critical management actions such as new invasive species occurrences.
Current CNPS Rare Plant Priority Species
Why are Rare Plant Ranks Important?
Our ranks help conservation organizations allocate limited resources and prioritize plants and habitats that are facing the most significant threats or are at the highest risk of extinction. Rarity and endangerment occur on a spectrum, and we determine ranks by looking at many factors, including number of populations, population size and trends, threats, and range.
What are California Rare Plant Ranks?
California Rare Plant Ranks (CRPRs) are a ranking system developed by CNPS to define and categorize rarity in the California flora. There are six CRPRs ranging from presumed extinct species (CRPR 1A) to limited distribution/watchlist species (CRPR 4). Visit the RPI Glossary to learn the criteria and see definitions of each rank.
One Known Occurence
OKO refers to plant species only known to exist in a single location. Some OKO plants have been reduced to single sites because of habitat loss, while others are naturally rare and occur in special habitats such as isolated desert wetlands or outcrops of unique rocks. Rarity is one of the best predictors of extinction risk, and plants known from a single location face many threats to their continued existence—making OKO plants a priority for conservation action.
What are Locally Rare Plants?
Since the late 1960s, CNPS has tracked and secured legal protection for California’s rare plants—today numbering over 2,000 taxa in the CNPS Inventory of Rare Plants—but the state’s vast size means many species common statewide yet declining locally due to habitat loss also need protection to preserve regional genetic diversity.
Local rare plant lists are maintained by several CNPS chapters:
Alameda — East Bay CNPS Rare Plant Database
Santa Barbara — Channel Islands Chapter Plant Lists
Ventura — 2022 Locally Important Plant List
How does Endangered Species Protection work?
For more than 50 years, CNPS has worked tirelessly to protect rare and endangered native plant species and their habitats. We believe that to save a plant, we must save its habitat—a focus that makes CNPS one of California’s most influential and long-standing advocates for land conservation. By saving plants, we save places.
The California and federal Endangered Species Acts (CESA and FESA) are two of the strongest wildlife protection laws in the country. California’s law more effectively protects plants than FESA does, thanks to clearer thresholds and a permit process—and the Native Plant Conservation Campaign (NPCC) is working to close that gap at the federal level.
Protection isn’t automatic. Each new development project requires the public and organizations like CNPS to actively invoke CESA and FESA—nobody does it for us.
Support Rare Plants with a CNPS Membership
