Taxon Report

Eriogonum heermannii Dur. & Hilg. var. occidentale S. Stokes

western Heermann's buckwheat

Print Report

Taxon Summary

Eriogonum heermannii var. occidentale, commonly known as western Heermann's buckwheat, is a perennial deciduous shrub in the Polygonaceae that is found only in California. It occurs within Cismontane woodland, growing at elevations from 105 to 795 meters. Eriogonum heermannii var. occidentale is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Eriogonum heermannii Dur. & Hilg. var. occidentale S. Stokes
Common Name:	western Heermann's buckwheat
Family:	Polygonaceae
Element Code:	PDPGN082P6
USDA Plants Symbol:	ERHEO
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial deciduous shrub
Blooming Period: Jul-Oct	Jul-Oct
Elevation:	105-795 (345-2610)
General Habitats:	Cismontane woodland
Microhabitat:	Clay (rarely), Roadsides (usually), Serpentine (often), Shale (rarely), Slopes (rarely)
Microhabitat Details:	usually alluvium floodplains

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G5T2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	BLM_S; SB_UCSC
CRPR Changes:	changed from 4.2 to 1B.2 on 2015-06-15

Occurrence Data from the CNDDB


Total Occurrences:	12
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	0
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	12

Location


California Endemic: True
California Counties and Islands: Name (Code)
Fresno (FRE), Monterey (MNT), San Benito (SBT)
Quads: Name (Quad Code)
Bickmore Canyon (3612152), Hepsedam Peak (3612037), Hernandez Reservoir (3612047), Idria (3612046), Lonoak (3612038), Panoche (3612057), Rock Spring Peak (3612048), Smith Mountain (3612015), Topo Valley (3612141), Tres Pinos (3612173)

Threat List Data from the CNDDB


Threat List Total:	2
EOs with Threat Listed:	Total EOs	% of EOs
	1	8 %
Erosion/runoff	1	8%
ORV activity	1	8%

Notes



Previously CRPR 4.2; rarer than originally thought. Possibly threatened by hydrological alterations caused by past vehicle use. See Leaflets of Western Botany 1(4):30 (1932) for original description, and Phytologia 66(4):314-316 (1989) for taxonomic treatment.
Threats:

Taxonomy:

Selected References

CRPR List Change on 2015-06-15

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 29 October 2025].