Rare Plant Rediscovered At Vasco Hills Regional Preserve After 68 Years

LIVERMORE, CA — The last time anyone saw this flower on public land, Eisenhower was president and Livermore's population was around 10,000 people.

A lot has changed in 68 years, including a proliferation of non-native plants threatening native ones. However, the East Bay Regional Park District announced Monday that a new population of the caper-fruited tropidocarpum, a yellow flower resembling a buttercup, was found in the Vasco Hills Regional Preserve.

The plant was undocumented for 68 years until a few individuals were observed on nearby private land in 2023, according to EBRPD. However, this marks the first time in 68 years that it was observed on protected public land.

“Our agencies are working together to conserve landscapes in eastern Contra Costa County that protect sensitive species while also providing recreation opportunities for the community,” said Park District General Manager Sabrina Landreth in a statement. “The discovery of this rare plant population illustrates the value of our partnership.”

The plant was first documented by UC Berkeley Professor Edward Lee Greene in 1888, who wrote that the species was “very common in the low alkaline valley lands skirting the San Joaquin River in Contra Costa County.”

Today, the caper-fruited tropidocarpum is listed as 1B.1 (rare, threatened, or endangered in California and elsewhere) by the California Native Plant Society. There are currently only two known populations in the East Bay, according to EBRPD.

“We have come a long way from the days when E.L. Greene said caper-fruited tropidocarpum was a common species,” said Heath Bartosh, a botanist of Nomad Ecology working on behalf of the East Contra Costa County Habitat Conservancy who discovered the plant alongside colleague Spencer Adams.

“Since the late 1880s, non-native species have become more abundant, outcompeting native species. This find highlights how crucial public land conservation and stewardship are to native plants.”

“Caper-fruited tropidocarpum is an elusive species that we had hoped would be found on one of our preserves. This inconspicuous plant has no shortage of suitable habitat on lands we’ve cooperatively preserved with the Park District,” said East Contra Costa County Habitat Conservancy Executive Director Abigail Fateman.

“Finding and documenting this new population required a thoughtful survey approach and persistence because annual plants may not germinate every year. This small population will be a high priority for monitoring and management for our team.”

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