Taxon Report

Clarkia borealis E. Small ssp. arida E. Small

Shasta clarkia

Print Report

Taxon Summary

Clarkia borealis ssp. arida, commonly known as Shasta clarkia, is a annual herb in the Onagraceae that is found only in California. It occurs within Cismontane woodland, and Lower montane coniferous forest (openings), growing at elevations from 490 to 595 meters. Clarkia borealis ssp. arida is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Clarkia borealis E. Small ssp. arida E. Small
Common Name:	Shasta clarkia
Family:	Onagraceae
Element Code:	PDONA05061
USDA Plants Symbol:	CLBOA
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Jun-Aug	Jun-Aug
Elevation:	490-595 (1610-1950)
General Habitats:	Cismontane woodland, Lower montane coniferous forest
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G4T2
State Rank:	S2?
State List:	None
Fed List:	None
Other Status:	BLM_S; SB_UCBG
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	6
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	1
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	4

Location


California Endemic: True
California Counties and Islands: Name (Code)
Shasta (SHA), Tehama (TEH)
Quads: Name (Quad Code)
Clough Gulch (4012251), Devils Rock (4012271), Inskip Hill (4012138)?, Oak Run (4012261), Shingletown (4012148)

Threat List Data from the CNDDB


Threat List Total:	1
EOs with Threat Listed:	Total EOs	% of EOs
	2	33 %
Road/trail construction/maint.	2	33%

Notes



Known from fewer than 10 occurrences near Shingletown. Very similar to ssp. borealis; study needed. See Canadian Journal of Botany 49:1211-1217 (1971) for original description.
Threats:

Taxonomy:

Selected References

Clarkia borealis ssp. arida account for potential Species of Conservation Concern evaluation (2020)

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 18 November 2025].