Taxon Report

Xylorhiza cognata (Hall) T.J. Watson

Mecca-aster

Print Report

Aaron E. Sims

Taxon Summary

Xylorhiza cognata, commonly known as Mecca-aster, is a perennial herb in the Asteraceae that is found only in California. It occurs within Sonoran desert scrub, growing at elevations from 20 to 400 meters. Xylorhiza cognata is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Xylorhiza cognata (Hall) T.J. Watson
Common Name:	Mecca-aster
Family:	Asteraceae
Element Code:	PDASTA1010
USDA Plants Symbol:	XYCO2
Synonyms/Other Names:	Machaeranthera cognata

Ecology and Life History


Lifeform:	perennial herb
Blooming Period: Jan-Jun	Jan-Jun
Elevation:	20-400 (65-1310)
General Habitats:	Sonoran desert scrub
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_CalBG/RSABG
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	36
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	6
Fair (C)	11
Poor (D)	0
None (X)	0
Unknown (U)	19

Location


California Endemic: True
California Counties and Islands: Name (Code)
Riverside (RIV)
Quads: Name (Quad Code)
Mecca (3311651), Mortmar (3311558), Myoma (3311673), Palm Springs (3311675), Thermal Canyon (3311661), West Berdoo Canyon (3311672)

Threat List Data from the CNDDB


Threat List Total:	8
EOs with Threat Listed:	Total EOs	% of EOs
	25	69 %
ORV activity	19	52%
Road/trail construction/maint.	4	11%
Erosion/runoff	3	8%
Vandalism/dumping/litter	2	5%
Development	2	5%
Recreational use (non-ORV)	2	5%
Mining	1	2%
Other	1	2%

Notes



Known mostly from Indio Hills and Mecca Hills.
Threats:
Threatened by vehicles. Potentially threatened by development. Possibly threatened by recreational activities.
Taxonomy:
See Brittonia 29:199-216 (1977) for revised nomenclature and description.

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 25 October 2025].