Taxon Report

Viola primulifolia L. ssp. occidentalis (Gray) L.E. McKinney & R.J. Little

western white bog violet

Print Report

Taxon Summary

Viola primulifolia ssp. occidentalis, commonly known as western white bog violet, is a perennial rhizomatous herb in the Violaceae that is found in California and elsewhere. It occurs within Bogs and fens (serpentinite), and Marshes and swamps, growing at elevations from 100 to 990 meters. Viola primulifolia ssp. occidentalis is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Viola primulifolia L. ssp. occidentalis (Gray) L.E. McKinney & R.J. Little
Common Name:	western white bog violet
Family:	Violaceae
Element Code:	PDVIO040Y2
USDA Plants Symbol:
Synonyms/Other Names:	Viola lanceolata L. ssp. occidentalis (Gray) Russell

Ecology and Life History


Lifeform:	perennial rhizomatous herb
Blooming Period: Apr-Sep	Apr-Sep
Elevation:	100-990 (330-3250)
General Habitats:	Bogs and fens, Marshes and swamps
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G5T2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	USFS_S
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	19
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	11
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	7

Location


California Endemic: False
California Counties and Islands: Name (Code)
Del Norte (DNT)
Quads: Name (Quad Code)
Gasquet (4112378), High Divide (4112481), High Plateau Mtn. (4112388), Hiouchi (4112471), Shelly Creek Ridge (4112387)

Threat List Data from the CNDDB


Threat List Total:	9
EOs with Threat Listed:	Total EOs	% of EOs
	9	47 %
Road/trail construction/maint.	3	15%
Other	2	10%
Altered flood/tidal/hydrologic regime	2	10%
Erosion/runoff	1	5%
Foot traffic/trampling	1	5%
Improper burning regime	1	5%
Logging	1	5%
ORV activity	1	5%
Vandalism/dumping/litter	1	5%

Notes



Threatened by mining, logging, road construction, and vehicles. Candidate for state listing in OR. See Botanical Gazette 11:255 (1886) for original description, and Phytologia 72(2):79 (1992) for revised nomenclature.
Threats:

Taxonomy:

Selected References

Viola primulifolia ssp. occidentalis profile for potential Species of Conservation Concern evaluation (2018)

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 19 November 2025].