Overview
- Botanist Heath Bartosh documented Tropidocarpum capparideum on March 3, 2025 in Vasco Hills Regional Preserve in eastern Contra Costa County.
- The sighting is the park's first in at least 68 years and represents one of two known populations, each with fewer than 20 plants.
- The species, first described as very common in 1888 by UC Berkeley botanist Edward Lee Greene, has dwindled due to invasive annual grasses and habitat loss from development.
- The East Contra Costa County Habitat Conservancy and the East Bay Regional Park District designated the tiny Vasco Hills population a high priority for monitoring and management.
- Because this annual may not emerge every year, staff credit conservation grazing and persistent, targeted surveys across the 14,000-acre managed landscape for enabling the rediscovery.