Taxon Report

Hesperolinon bicarpellatum (H.K. Sharsm.) H.K. Sharsm.

two-carpellate western flax

Print Report

Taxon Summary

Hesperolinon bicarpellatum, commonly known as two-carpellate western flax, is a annual herb in the Linaceae that is found only in California. It occurs within Chaparral, growing at elevations from 60 to 1005 meters. Hesperolinon bicarpellatum is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Hesperolinon bicarpellatum (H.K. Sharsm.) H.K. Sharsm.
Common Name:	two-carpellate western flax
Family:	Linaceae
Element Code:	PDLIN01020
USDA Plants Symbol:	HEBI3
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: (Apr)May-Jul	(Apr)May-Jul
Elevation:	60-1005 (195-3295)
General Habitats:	Chaparral
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	BLM_S; SB_UCSC
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	25
Element Occurrence Ranks:
Excellent (A)	5
Good (B)	2
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	18

Location


California Endemic: True
California Counties and Islands: Name (Code)
Lake (LAK), Napa (NAP), Sonoma (SON)
Quads: Name (Quad Code)
Aetna Springs (3812264), Bartlett Mtn. (3912227), Clearlake Highlands (3812286), Detert Reservoir (3812265), Jericho Valley (3812274), Lucerne (3912217), Middletown (3812275), Mount St. Helena (3812266), Whispering Pines (3812276), Wilbur Springs (3912214)

Threat List Data from the CNDDB


Threat List Total:	5
EOs with Threat Listed:	Total EOs	% of EOs
	6	24 %
Road/trail construction/maint.	5	20%
Erosion/runoff	4	16%
Grazing	3	12%
Other	1	4%
Development	1	4%

Notes



Previously confused with H. serpentinum, which also occurs on serpentinite soils in the same general area. Threatened by development and grazing. See University of California Publications in Botany 32:235-314 (1961) for taxonomic treatment.
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 26 October 2025].