In the rocky foothills of California, from Sonoma wine country to the snow-covered crests of the Sierra, a small, unassuming wildflower is quietly teaching scientists how to save thousands of plant species from the grip of climate change. The mountain jewelflower (Streptanthus tortuosus) appears hardy enough to thrive almost anywhere—yet researchers at UC Davis have discovered it is surprisingly vulnerable to the very shifts it has survived for millennia.
This vulnerability matters because California's climate is changing faster than the plants that depend on ancient rainfall patterns. Since 1960, the state's wet season has drifted later into fall, with rain and snow that once arrived in October now often held back until November or December. For a wildflower whose seeds are tuned to germinate at a precise moment, this shift pulls the rug out from under survival itself.
Jennifer Gremer, an associate professor in UC Davis's Department of Evolution and Ecology, has spent a decade studying California's jewelflowers alongside her colleagues Julin Maloof, Sharon Strauss, and Johanna Schmitt. Their work is rooted in a decade-long insight: plants living in unpredictable climates have evolved ingenious ways to bet on the future. During earlier research in the Sonoran Desert, Gremer found that annual flowers like the Mojave Desert star produce seeds that germinate on different schedules—some waiting one year, others up to twelve years—ensuring that drought cannot wipe out an entire species in a single season.
Jewelflowers present a natural experiment in climate adaptation. California harbors more than thirty species of these ornate wildflowers, thought to have evolved from a single ancestral desert species. While the mountain jewelflower roams across an impressive range of local climates, jewelflowers collectively inhabit an even more remarkable span, from northern Mexico through California, Oregon, Arizona, and Nevada. Each species occupies distinct niches: some flourish on sun-bathed rocky slopes, others have adapted to metal-rich serpentine soils that poison many plants.
By studying how jewelflower seeds germinate and how that germination shapes their later success, Gremer and her team hope to unlock lessons applicable far beyond a single species. California harbors thousands of native plants whose survival is interwoven with countless birds, insects, and entire ecosystems. The task of shepherding all of them through climate change is potentially overwhelming—but understanding how jewelflowers adapt could provide a roadmap.
"Our goal is for our insights to be applicable to many different species," Maloof said, capturing the ambition of their research. The insights gained from jewelflowers could identify other at-risk species and help them adapt to a rapidly shifting climate. In this quiet work—examining seeds, measuring germination timing, and reading the stories plants have written into their biology—lies the possibility of protecting not just a flower, but entire California ecosystems poised on the edge of change.