Taxon Report

Sidalcea oregana (Nutt.) Gray ssp. valida (Greene) C.L. Hitchc.

Kenwood Marsh checkerbloom

Print Report

Taxon Summary

Sidalcea oregana ssp. valida, commonly known as Kenwood Marsh checkerbloom, is a perennial rhizomatous herb in the Malvaceae that is found only in California. It occurs within Marshes and swamps, growing at elevations from 115 to 150 meters. Sidalcea oregana ssp. valida is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Sidalcea oregana (Nutt.) Gray ssp. valida (Greene) C.L. Hitchc.
Common Name:	Kenwood Marsh checkerbloom
Family:	Malvaceae
Element Code:	PDMAL110K5
USDA Plants Symbol:	SIORV
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial rhizomatous herb
Blooming Period: Jun-Sep	Jun-Sep
Elevation:	115-150 (375-490)
General Habitats:	Marshes and swamps
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G5T1
State Rank:	S1
State List:	CE
Fed List:	FE
Other Status:	SB_CalBG/RSABG; SB_UCBG
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	2
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	0
Fair (C)	2
Poor (D)	0
None (X)	0
Unknown (U)	0

Location


California Endemic: True
California Counties and Islands: Name (Code)
Sonoma (SON)
Quads: Name (Quad Code)
Kenwood (3812245), Mount St. Helena (3812266)

Threat List Data from the CNDDB


Threat List Total:	6
EOs with Threat Listed:	Total EOs	% of EOs
	2	100 %
Grazing	2	100%
Non-native plant impacts	2	100%
Other	2	100%
Surface water diversion	1	50%
Agriculture	1	50%
Foot traffic/trampling	1	50%

Notes



Known from only two occurrences. Threatened by grazing and hydrological alteration, and possibly by competition with native and non-native plants. See Pittonia 3:157-158 (1897) for original description, and University of Washington Publications in Biology 18:56-58 (1957) for revised nomenclature.
Threats:

Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 17 November 2025].