Taxon Report

Eriogonum truncatum T. & G.

Mt. Diablo buckwheat

Print Report

Taxon Summary

Eriogonum truncatum, commonly known as Mt. Diablo buckwheat, is a annual herb in the Polygonaceae that is found only in California. It occurs within Chaparral, Coastal scrub, and Valley and foothill grassland, growing at elevations from 3 to 350 meters. Eriogonum truncatum is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Eriogonum truncatum T. & G.
Common Name:	Mt. Diablo buckwheat
Family:	Polygonaceae
Element Code:	PDPGN085Z0
USDA Plants Symbol:	ERTR11
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Apr-Sep(Nov-Dec)	Apr-Sep(Nov-Dec)
Elevation:	3-350 (10-1150)
General Habitats:	Chaparral, Coastal scrub, Valley and foothill grassland
Microhabitat:	Sandy
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G1
State Rank:	S1
State List:	None
Fed List:	None
Other Status:	SB_UCBG
CRPR Changes:	changed from 1A to 1B on 2005-07-01

Occurrence Data from the CNDDB


Total Occurrences:	7
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	0
Fair (C)	0
Poor (D)	0
None (X)	1
Unknown (U)	5

Location


California Endemic: True
California Counties and Islands: Name (Code)
Contra Costa (CCA), Solano (SOL)*
Quads: Name (Quad Code)
Antioch North (3812117), Antioch South (3712187), Clayton (3712188)?, Diablo (3712178), Fairfield South (3812221)

Threat List Data from the CNDDB


Threat List Total:	2
EOs with Threat Listed:	Total EOs	% of EOs
	2	29 %
Development	1	14%
Non-native plant impacts	1	14%

Notes



Rediscovered in May 2005 by Michael Park in Mount Diablo SP; now known from one extant occurrence for which quad location needs confirmation. Potentially threatened by trampling and non-native plants. Much habitat eliminated by urbanization. See Proceedings of the American Academy of Arts and Sciences 8:173 (1870) for original description, and Phytologia 66(4):375-376 (1989) for taxonomic treatment.
Threats:

Taxonomy:

Selected References

CRPR List Change on 2005-07-01

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 15 November 2025].