Succulent Owl's Clover
See photo info below

Sacramento Fish & Wildlife Office
Species Account

SUCCULENT OWL'S-CLOVER
(Castilleja campestris ssp. succulenta)

CLASSIFICATION: Federal Threatened Species (Federal Register 62:14338 [pdf]; March 26, 1997)

This subspecies was listed as endangered by the California Department of Fish and Game in January 1990, under the name succulent owl's-clover. The California Native Plant Society has placed it on List 1B (rare or endangered throughout its range), also as succulent owl's-clover.

CRITICAL HABITAT: Originally designated in Federal Register 68:46683 pdf; August 6, 2003.
The designation was revised in 70:46923 pdf; August 11, 2005. Species by unit designations were published in 71:7117 (pdf) February 10, 2006.

RECOVERY PLAN: Recovery Plan for Vernal Pool Ecosystems of California and Southern Oregon

DESCRIPTION:

Succulent owl's-clover (Castilleja campestris ssp. succulenta), also known as fleshy owl's-clover, is an annual herb in the snapdragon family (Scrophulariaceae). Its stems are erect, generally 2-10 inches tall, and may be branched or unbranched. The leaves are succulent and brittle.

Bright yellow to white flowers appear in May, clustered near the ends of branches and surrounded by leafy bracts.

Like other members of Castilleja and related genera, it is partly parasitic (hemiparasitic) on the roots of other plants. It occurs on the margins of vernal pools, swales and some seasonal wetlands, often on acidic soils. It is never dominant and it is found in only a few of the pools in an area.

The species' range overlaps that of the related Castilleja campestris ssp. campestris in Stanislaus County, but the latter can be distinguished by its usually more brittle leaves, shorter bracts, larger corollas and longer stigmata. See Hickman (1993) in General Information about California Plants, below, for a detailed description of both species.

DISTRIBUTION:

Succulent owl's-clover is found only in vernal pools along the rolling lower foothills and valleys along the eastern San Joaquin Valley in the Southern Sierra Foothills Vernal Pool Region.

Through August 2005, the California Natural Diversity Data Base had catalogued 91 occurrences. About one third of these occurrences are records from Merced County, catalogued in association with rare plant and wildlife surveys of eastern Merced County grass and ranch lands conducted during 2001 by a team of consultants to the Countyand California Department of Fish and Game (Vollmar 2002).

THREATS:

Habitat loss and fragmentation are the largest threats to the survival and recovery of vernal pool species. Loss of habitat generally results from urbanization, agricultural conversion and mining.

Habitat loss also occurs in the form of habitat alteration and degradation as a result of changes to natural hydrology, invasive species, incompatible grazing regimes, infrastructure projects (e.g., roads, water storage and conveyance, utilities), recreational activities (e.g., off-highway vehicles and hiking), erosion, contamination and inadequate management and monitoring.

One significant specific threat is the proposed construction of the new University of California campus in Merced County. This project, plus associated residential development and access roads, are threats to the primary and relatively extensive population in that area.

Additional urban developments threaten many other known occurrences, including planned housing subdivisions in Fresno, Madera and San Joaquin Counties, a freeway expansion in Madera County and a proposed landfill in Fresno County.

Invasive nonnative species pose a significant threat. Exclusion of grazing from sites that have been grazed historically may increase the threat of nonnative plants.

Threats due to alterations in natural hydrology include the Merced County Stream Channel Project \ proposed by the U.S. Army Corps of Engineers and proposed enlargement of Burns Reservoir in Merced County./p>

REFERENCES FOR ADDITIONAL INFORMATION: (See our Disclaimer)

U.S. Fish & Wildlife Service. 1997. Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Three Plants and Threatened Status for Five Plants From Vernal Pools in the Central Valley of California. Portland, Oregon.

U.S. Fish and Wildlife Service. 2003. Endangered and Threatened Wildlife and Plants; Final Designation of Critical Habitat for Four Vernal Pool Crustaceans and Eleven Vernal Pool Plants in California and Southern Oregon Vernal pool crustaceans and plants in California and Oregon. Portland, Oregon.

U.S. Fish and Wildlife Service. 2005. Endangered and Threatened Wildlife and Plants; Final Designation of Critical Habitat for Four Vernal Pool Crustaceans and Eleven Vernal Pool Plants in California and Southern Oregon; Evaluation of Economic Exclusions From August 2003 Final Designation; Final Rule. Portland, Oregon.

U.S. Fish and Wildlife Service. 2006. Endangered and Threatened Wildlife and Plants: Designation of Critical Habitat for Four Vernal Pool Crustaceans and Eleven Vernal Pool Plants; Final Rule. Portland, Oregon.

U.S. Fish and Wildlife Service. 2005. Recovery Plan for Vernal Pool Ecosystems of California and Southern Oregon. Portland, Oregon.

Vollmar, J. E. (editor). 2002. Wildlife and rare plant ecology of eastern Merced County’s vernal pool grasslands. Merced, California: Merced County UC Development Office.

General Information about California Plants

Photo credit: Succulent Owl's Clover © 2000 Robert E. Preston, Ph.D. Calphoto ID: 0000 0000 0102 0073

Prepared by Endangered Species Div., Sacramento Fish & Wildlife Office, U.S. Fish & Wildlife Service