Scadden Flat Checkerbloom

(Sidalcea stipularis)

Scadden Flat checkerbloom is listed as a California endangered plant species, which means that killing or possessing plants from the wild is prohibited by the California Endangered Species Act (CESA). Scadden Flat checkerbloom is a perennial herb that typically produces flowers with pink petals from June to August. Scadden Flat checkerbloom has been found growing in wet montane marshes that are fed by local springs. Only three small populations of this species have been found, all near Grass Valley in Nevada County, California. Two of the populations are west of Grass Valley along the south side of Highway 20 on private land and on land owned by the California Department of Transportation. These populations together are the largest known occurrence of the species and some plants at this occurrence were transplanted here in the past. The third known population has been observed to historically support low numbers of plants and is located on private property to the southeast of Grass Valley. This population may be negatively affected by mowing and altered water flows.

Populations of Scadden Flat checkerbloom are threatened by highway widening, herbicide spraying, herbivory, trampling, altered hydrology and encroachment by Himalayan blackberry (Rubus armeniacus) or other non-native or native species. Scadden Flat checkerbloom may also be threatened by climate change or random natural or human-caused events. Scadden Flat checkerbloom may be especially vulnerable to extinction due to its small population sizes and the small number of known populations. CDFW participated in seed collection efforts for Scadden Flat checkerbloom with support from the Cooperative Endangered Species Conservation Fund.

Cooperation with landowners and the California Department of Transportation is crucial to ensure the continued existence of this species. Populations of Scadden Flat checkerbloom should be monitored using standardized protocols, and the current threats to the species should be re-assessed regularly. Measures should also be implemented to reduce threats to the species from encroaching Himalayan blackberry and other species.

CDFW may issue permits for Scadden Flat checkerbloom pursuant to CESA, and you can learn more about the California laws protecting Scadden Flat checkerbloom and other California native plants. Populations of Scadden Flat checkerbloom occur in CDFW’s North Central Region.

Updated 12/8/2015

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Image of a flower with pink petals in front of a dark background
Sidalcea stipularis, Photo © Rick York and CNPS
Sidalcea stipularis, CDFW illustration by Mary Ann Showers
Sidalcea stipularis, CDFW illustration by Mary Ann Showers, click for full-sized image