National Collection of Rare and Endangered Plants

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By: Cheryl Birker, California Botanic GardenDuncan Bell collects Panamint Mountains buckwheat at Death Valley NP

Bringing Rarity Together

The Center for Plant Conservation maintains a collection of more than 2,600 of America’s most imperiled native plants through its network of world class botanical gardens. Our 75 Institutional Conservation Partners safeguard endangered plant material in “ex situ” botanical collections including seed banks, nurseries, and garden displays. An important conservation resource, the National Collection serves as an emergency backup in case a species becomes extinct or no longer reproduces in the wild. To communicate this important work, CPC and its network of conservation experts actively update web profiles for all National Collection species, which serve as a historical record of conservation actions taken to save these rare plants. Search the National Collection and view the plant profiles to learn more about these beautiful, imperiled rare plants and the gardens that conserve them.

Collection Statistics

Institutional Conservation Partners
Species in the National Collection
Conservation Collections

Cedros Island Oak

(Quercus cedrosensis)

Cedros Island Oak (Quercus cedrosensis) is an imperiled oak species native primarily to Cedros Island in Baja California, Mexico, with one population occurring in San Diego, CA, at Otay Mountain. Major threats to this species include drought, wildfire, and border activitis. Oaks are exceptional species, meaning they cannot be stored using traditional seed banking methods, and are often conserved in living collections or other forms of long-term storage (such as cryopreservation). In 2017, only one individual of Quercus cedrosensis was known to be held ex situ in conservation collection.

Now, Quercus cedrosensis is secured in the CPC National Collection at San Diego Botanic Garden (SDBG), San Diego Zoo Wildlife AllianceCalifornia Botanic Garden, and The Huntington. Genetic material from this species at the Otay Mountain population has been collected in the form of cuttings and a few acorns, grown as a living conservation genebank by San Diego Botanic Garden with seedlings held in their nursery and distributed to The Huntington. Seeds from this species are hard to come by, with many wild individuals producing little to no acorns, making cuttings a helpful tool for conservation collections.

Learn more about conservation actions taken for Cedros Island Oak on its National Collection Plant Profile and help support critical conservation work for this species with a Plant Sponsorship. This species is part of CPC’s 40th Anniversary Campaign! In celebration of our 40 years of saving plants from extinction, we are raising funds to sponsor 40 National Collection species, including Cedros Island Oak. For every $5K raised per plant species, our Board of Trustees will provide $5K in matching funds to bring the species to the full sponsorship level of $10K–growing the impact of your gift in support of rare and endangered plants. Learn more about our 40th Anniversary Campaign.

Background photo: Quercus cedrosensis in situ in Mexico. Photo Credit: Carlos Gonzalez.

CPC National Collection Search

The Center for Plant Conservation’s National Collection of Endangered Plants contains plant material for more than 2,500 of the country’s most imperiled native plants. An important conservation resource, the National Collection is a backup in case a species becomes extinct or no longer reproduces in the wild. Search the National Collection and view the plant profiles to learn more about these beautiful, imperiled plants.

Visit our Rare Plant Finder for a More Advanced Search
By: Jennifer Possley Passiflora sexflora

Sponsor a Plant in the National Collection

To offset some of the expenses of collecting, growing, and researching plant species in the National Collection, the Center for Plant Conservation created the Plant Sponsorship Program to provide Participating Institutions responsible for a named species stable funding for the long-term work. A sponsorship does not cover all the expenses, but it provides significant help and stability, and has a critical and lasting impact on plant conservation efforts.

News from our Save Plants Digest

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Save Plants: December 2023 Newsletter

As we approach the end of another amazing year in conservation, we wish to reflect on some of the ma...

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As Seen on CPC’s Rare Plant Academy: Photo Posting Tool

Have you used the photo posting tool on the Rare Plant Academy? Adding photos to the Plant Profiles ...

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National Collection Spotlight: Tiburon Mariposa Lily

Tiburon Mariposa Lily (Calochortus tiburonensis) is a critically imperiled lily species endemic to a...


With your help we can safeguard more of the unique plants in peril and in need of protection by adding them to the National Collection and conserving them in the wild.

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