New Species Discovered on Lime Ridge

July 21, 2008

This summer, plant experts announced a rare and exciting discovery at Lime Ridge Open Space, close to Mount Diablo State Park. Amateur botanist David Gowen found two previously unidentified plants, now named the Lime Ridge navarretia (Navarretia gowenii) and the Lime Ridge woollystar (Eriastrum sp. nov.), that survived unnoticed on a patch of protected land almost completely surrounded by the cities of Walnut Creek and Concord.

The diminutive plants, which belong to the phlox family, are not plentiful even where they were found, and Gowen found them through careful observation of an area famous botanists have studied in the past.

“Amateur’s not the right word [for Gowen]. He has this great power of observation, he pays close attention to detail,” said Leigh Johnson, a Brigham Young University professor who specializes in the genus Navarretia. “If he hadn’t done that then the plant would have been overlooked.”

Lime Ridge navarretia
Lime Ridge navarretia. Photo by Scott Hein.

The flowers’ survival is an exciting example of the benefits of protecting open spaces in urban areas, even places that have seen considerable human use. “This isn’t in some foreign country or in the boonies,” says Gowen, a member of the East Bay chapter of the California Native Plant Society. “It’s in the heart of an urbanized environment. If a housing development had destroyed this site, the plant might have vanished off the earth without anyone ever knowing.” Indeed, it was the specter of a housing development on these lands that precipitated their acquisition, along with several other land preserves, by the city of Walnut Creek in 1974.

Despite the extensive lime quarrying that began here in the mid-19th century and continued for 100 years, the ridge remains rich in rare native plants. Says Gowen, “It’s a wild place, full of rare plants, full of rare animals. It’s less a park than a natural preserve.” Though it was preserved over 30 years ago, the space has been open to the public only since 1997.

Lime Ridge woollystar

Lime ridge woollystar. Photo by Scott Hein.

Just three years ago, botanist Michael Park found the Mount Diablo buckwheat, a wildflower long thought extinct, on an open patch of soil in land recently added to Mount Diablo State Park. This plant hadn’t been seen since the 1930s and, until Park’s discovery, it was considered a local “holy grail.”

In fact, Gowen originally visited Lime Ridge ten years ago in hopes of finding the Mount Diablo buckwheat. “I began looking for the Mount Diablo buckwheat after a lecture Barbara Ertter [curator of Western North American flora at the Jepson Herbarium] gave at the botanical garden, challenging botanists to go out and find this thing,” he says.

Thanks to his efforts, the navarretia and woollystar join the buckwheat as living proof that even relatively small pieces of habitat can harbor surprising diversity. And Gowen joins Park in proving that both amateur and professional botanists can make remarkable discoveries. “The cool thing about not one but TWO new plant species from Lime Ridge,” says Ertter, “is the proof that the age of discovery is still alive, in our own backyards.”

About the Author

Laura Hautala is a freelance reporter based in Oakland.

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