Taxon Report

Phacelia phacelioides (Benth.) Brand

Mt. Diablo phacelia

Print Report

Taxon Summary

Phacelia phacelioides, commonly known as Mt. Diablo phacelia, is a annual herb in the Hydrophyllaceae that is found only in California. It occurs within Chaparral, and Cismontane woodland, growing at elevations from 500 to 1370 meters. Phacelia phacelioides is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Phacelia phacelioides (Benth.) Brand
Common Name:	Mt. Diablo phacelia
Family:	Hydrophyllaceae
Element Code:	PDHYD0C3Q0
USDA Plants Symbol:	PHPH
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Apr-May	Apr-May
Elevation:	500-1370 (1640-4495)
General Habitats:	Chaparral, Cismontane woodland
Microhabitat:	Rocky
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_CalBG/RSABG
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	40
Element Occurrence Ranks:
Excellent (A)	2
Good (B)	4
Fair (C)	0
Poor (D)	1
None (X)	0
Unknown (U)	33

Location


California Endemic: True
California Counties and Islands: Name (Code)
Alameda (ALA), Contra Costa (CCA), Fresno (FRE), San Benito (SBT), Santa Clara (SCL), Stanislaus (STA)
Quads: Name (Quad Code)
Clayton (3712188), Copper Mtn. (3712143), Diablo (3712178), Eylar Mtn. (3712145), Idria (3612046), Isabel Valley (3712135), Lick Observatory (3712136), Lone Tree Creek (3712154), Mississippi Creek (3712124), Mt. Boardman (3712144), Mt. Stakes (3712134), San Benito Mtn. (3612036), Santa Rita Peak (3612035), Solyo (3712153)

Threat List Data from the CNDDB


Threat List Total:	5
EOs with Threat Listed:	Total EOs	% of EOs
	3	8 %
Road/trail construction/maint.	2	5%
Erosion/runoff	1	2%
Foot traffic/trampling	1	2%
Grazing	1	2%
Non-native plant impacts	1	2%

Notes



Known from fewer than twenty occurrences. Many occurrences historical; need field surveys. Possibly threatened by foot traffic and trail construction.
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 30 January 2025].