Coast Yellow Leptosiphon

(Leptosiphon croceus)

Coast yellow leptosiphon is a California endangered plant species, which means that killing or possessing plants is prohibited by the California Endangered Species Act (CESA). Coast yellow leptosiphon is a low-growing annual plant in the Phlox family (Polemoniaceae) that grows to a height of 2 to 7 centimeters (0.8 to 2.8 inches). Coast yellow leptosiphon produces bright yellow flowers with fused petals that often have two bright red dots at the base. The flowers are arranged in heads and generally appear from April to June.

Coast yellow leptosiphon is known from only one small population that is located on Vallemar Bluff in Moss Beach, San Mateo County. The population occupies an area of approximately 167 square meters (1,800 square feet) and is located at the edge of the coastline on a marine terrace supported by sedimentary sandstone-derived soil. It occurs on a bluff at an elevation of 14 meters (46 feet), in habitat that is highly influenced by wind, cool salt-laden air, and fog.

The population of coast yellow leptosiphon occurs in close proximity to urban land use and has been directly and indirectly impacted by modification and destruction of habitat. The primary threats to coast yellow leptosiphon are development and other land-use changes, erosion, and encroachment of invasive plant species. Climate change also threatens the persistence of coast yellow leptosiphon and will likely accelerate erosion of the bluff where the species grows. Human activities such as trampling also threaten coast yellow leptosiphon. In addition, coast yellow leptosiphon is highly vulnerable to extinction due to its extremely limited distribution and restriction to only one small population. Due to the extremely limited distribution of coast yellow leptosiphon and its small population size, the loss of any portion of its population would be considered the loss of a significant portion of the species total range and would likely result in the extinction of this species.

Permanent protection and management of the occupied and adjacent coast yellow leptosiphon habitat is critical to preventing extinction of the species. The life history characteristics of coast yellow leptosiphon should be researched, including factors related to pollination, seed dispersal, seed longevity and soil seed bank, seed productivity, growth, propagation, and microhabitat requirements for germination and recruitment. Seeds of coast yellow leptosiphon should be collected and bulked for long-term conservation storage and potential introduction into suitable habitat. Potential coast yellow leptosiphon habitat near the existing population should be identified, and introduction of seeds should be considered.

The California Department of Fish and Wildlife (CDFW) completed a Status Review of Coast Yellow Leptosiphon (PDF) in 2018, which provides detailed information on the biology and population trends of coast yellow leptosiphon and an analysis of the factors affecting the ability of the species to survive and reproduce.

CDFW may issue permits for coast yellow leptosiphon pursuant to CESA, and you can learn more about the California laws protecting coast yellow leptosiphon and other California native plants . Coast yellow leptosiphon occurs in CDFW’s Bay Delta Region.

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A small plant with green bracts and yellow flowers with long flower tubes. The plant is next to a U.S. dime to illustrate scale. The dime is about one-fifth the size of the plant.
Leptosiphon croceus, CDFW photo by Cherilyn Burton
A sea cliff over the Pacific Ocean on a clody day with a walking path on the right and a bench overlooking the sea. This shows the location of the entire population of Coast Yellow Leptosiphon.
Leptosiphon croceus habitat, CDFW photo by Cherilyn Burton