About

Camissonia benitensis is a species of evening primrose known by the common names San Benito suncup and San Benito evening primrose. It is endemic to the Diablo Range of the South Coast Ranges of California, where its range includes far southern San Benito County, far western Fresno County, and far eastern Monterey County.

The species is categorized as a strict serpentine endemic, meaning that it is almost always found growing on serpentine soils; however, at least 10 populations of the species are known to occur on greywacke substrates. Most of the habitat of the species is associated with the New Idria Serpentine Mass, Laguna Mountain Serpentine Mass, Hepsedam Peak Serpentine Mass, Panther Peak Serpentine Mass, Mustang Ridge Serpentine Mass, and numerous smaller serpentine masses between.

Where it grows

Based upon the original discovery of C. benitensis on a serpentine alluvial stream terrace adjacent to Clear Creek, it was long believed that its only habitat type consisted of serpentine alluvial terraces adjacent to perennial streams and rivers, a very rare type of habitat. Until 2010 few populations of the species had been found in any other habitat. In 2010 numerous additional populations were discovered on other land forms including ancient serpentine alluvium deposits (upland hills), serpentine landslides originating from tectonic masses (upland), and serpentine soils on the periphery of large tectonic serpentine (ultramafic) masses (upland)(USFWS 2020). These recently discovered habitat types are collectively called the "geologic transition zone." This habitat type is now known to constitute the majority of the habitat area and contains most of the known populations of the species (USFWS 2020). Populations found near Priest Valley in 2010 extended the previously known range 15 kilometers to the southeast (USFWS 2020).

Other Camissonia plants

Mojave suncup · Plains evening primrose · Grassland suncup · Lewis River suncup · Hairy suncup · Little wiry suncup · Sandysoil suncup · Suncup