Lewis' Evening Primrose [Camissonia lewisii Raven]

Lewis' Evening Primrose [Camissonia lewisii Raven]

Listing CNPS List 3 R-E-D Code ?-?-2

State/Federal. Status -- None ONAGRACEAE Mar.-Jun.

Global Rank G? State Rank S?

Distribution: San Diego County, Orange County, Los Angeles County; Baja California, Mexico

Habitat: This small annual grows in very sandy substrates near the beach, typically on beach bluffs. In the Tijuana Hills it was observed on soils mapped as Chino fine sandy loams.

Known Sites: This species is rare near the coastal strand at Border Field, Spooner's Mesa in the Tijuana Hills, and at the western edge of Otay Mesa. Several plants were observed on an isolated hillside abutting the Penasquitos Lagoon adjacent to the freeway. Herbarium specimens examined were from Balboa Park, Otay Lakes Road, Silver Strand, San Luis Rey, Crown Point, the south end of San Diego Bay, and near Old Town. Some of the reported locales for San Diego County are now within the boundaries of the urbanized coastal cities where it is likely extirpated. Other reported sites include Fallbrook, Agua Hedionda, San Pasqual, Bonita, and Jamul. Roberts reports this species as quite rare and possibly extirpated in Orange County. Raven notes this species is rare at Point Dume in the Santa Monica Mountains. A herbarium specimen was examined from the El Segundo Dunes.

Nineteen specimens are found at the herbarium of the San Diego Natural History Museum, south to 28 10' North where collected by Moran (SD 92335) at Arroyo de la Purificacion.

Status: Lewis' Evening Primrose is severely declining in San Diego County, and likely throughout its U.S. range. Some of the reported inland locales may represent misidentifications; this genus is notoriously difficult and can superficially mimic the relatively common Camissonia bistorta or Camissonia micrantha. The small stature of the plant, thick quadrangular seed capsule, and sandy microhabitat near the beach are typical of this species. Focused surveys of all known historical sites and potential coastal habitat are necessary to make more definitive assessments. This species could be extremely rare or approaching extirpation in the U.S. More information is needed. Until such information is available, all populations should be protected.

Copyright May 1994 Craig H. Reiser.

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