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Santa Ana River Woollystar

(Eriastrum densifolium ssp. sanctorum)

Santa Ana River woolly-star is a California endangered plant species, which means that killing or possessing the plant is prohibited by the California Endangered Species Act (CESA). Santa Ana River woolly-star is a subshrub that generally does not grow taller than one meter. It has light grey-green stems and leaves with bright blue funnel-shaped flowers. It flowers between May and August, most heavily in June, and fruits from July to mid-October. Santa Ana River woolly-star is also listed as endangered under the federal Endangered Species Act.

Santa Ana River woolly-star is endemic to the Santa Ana River drainage in southern California. It thrives in open areas that receive a lot of sun and where there are infrequent flood events that contribute to seed dispersal. Santa Ana River woolly-star grows in sandy areas and is a pioneer species, meaning that it will take over previously unutilized habitat. It requires periodic flooding along with scouring and sediment deposition to persist. At the time of this webpage posting, the California Natural Diversity Database (CNDDB) reports 18 occurrences presumed to still exist. These occurrences are primarily within San Bernardino County, with a small number occurring in Riverside County. Historical occurrences of Santa Ana River woolly-star are known from Orange County, but it has been extirpated from those locations. Consistent population counts have not been available, so it is difficult to establish population level trends for the plant.

Some historical occurrences of Santa Ana River woolly-star were extirpated due to habitat degradation resulting from urban and agricultural development that altered hydrological regimes within the floodplain. Development within the floodplain continues to threaten remaining occurrences of Santa Ana River woolly-star. Other threats include mining, altered hydrology, unauthorized off-highway vehicle usage, hybridization with related subspecies, and climate change. Some occurrences of Santa Ana River woolly-star are protected from direct development by the Western Riverside County Multiple Species Habitat Conservation Plan, but to ensure the persistence of Santa Ana River woolly-star, remaining occurrences should be protected from development.

CDFW may issue permits for Santa Ana River woolly-star pursuant to CESA, and you can learn more about the California laws protecting Santa Ana River woolly-star and other California native plants. Populations of Santa Ana River woolly-star occur in CDFW’s Inland Deserts Region. More information is also available from the U.S. Fish and Wildlife Service Species Profile for Santa Ana River woolly-star.

Updated 12/8/2015


For more information on any of the topics above, please contact the Native Plant Program at nativeplants@wildlife.ca.gov.

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Habitat Conservation Planning Branch
1416 Ninth Street, 12th Floor, Sacramento, CA 95814
(916) 653-4875


Eriastrum densifolium ssp. sanctorum, Photo © Shannon Lucas 

Line drawing of Eriastrum densifolium

Eriastrum densifolium ssp. sanctorum CDFW illustration by Mary Ann Showers, click for full-sized image