Taxon Report

Eriogonum microtheca Nutt. var. johnstonii Rev.

Johnston's buckwheat

Print Report

Taxon Summary

Eriogonum microtheca var. johnstonii, commonly known as Johnston's buckwheat, is a perennial deciduous shrub in the Polygonaceae that is found only in California. It occurs within Subalpine coniferous forest, and Upper montane coniferous forest, growing at elevations from 1829 to 2926 meters. Eriogonum microtheca var. johnstonii is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.

Classification


Scientific Name:	Eriogonum microtheca Nutt. var. johnstonii Rev.
Common Name:	Johnston's buckwheat
Family:	Polygonaceae
Element Code:	PDPGN083W5
USDA Plants Symbol:	ERMIJ
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial deciduous shrub
Blooming Period: Jul-Sep	Jul-Sep
Elevation:	1829-2926 (6000-9600)
General Habitats:	Subalpine coniferous forest, Upper montane coniferous forest
Microhabitat:	Rocky
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.3
Global Rank:	G5T2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	SB_CalBG/RSABG; USFS_S
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	7
Element Occurrence Ranks:
Excellent (A)	2
Good (B)	0
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	5

Location


California Endemic: True
California Counties and Islands: Name (Code)
Los Angeles (LAX), San Bernardino (SBD)
Quads: Name (Quad Code)
Big Bear City (3411637), Cucamonga Peak (3411725), Fawnskin (3411638), Mount San Antonio (3411736), Onyx Peak (3411626)

Threat List Data from the CNDDB


Threat List Total:	6
EOs with Threat Listed:	Total EOs	% of EOs
	4	57 %
Foot traffic/trampling	2	28%
Grazing	2	28%
Mining	1	14%
Over-collecting/poaching	1	14%
Recreational use (non-ORV)	1	14%
Road/trail construction/maint.	1	14%

Notes



Known from fewer than ten occurrences; most in designated wilderness areas. Angeles NF has adopted species management guidelines. Threatened by mining and recreational activities. See Phytologia 66(4):313 (1989) 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 3 July 2025].